I've published a couple of 'major' articles here now. They're both still works in progress.
I've noticed something about them that I should find quite unsettling, but don't. I seem to have a bit of difficulty keeping person and tense consistent. There's a reason for that.
My perspective often changes as I go. Sometimes I'm writing in complete hindsight, relating how an operation or a sequence of operations was/were performed. Sometimes I'm writing about what I'm going to do next. Sometimes I'm writing practically in the moment, as I arrive at a point of discovery or decision, and I feel as if the reader is in the shop with me to witness it.
Consequently, my sense of person and tense fluctuates, and I'm not sure I have the intellectual wherewithal to resolve that perfectly, so I'm not even going to try. This is a different medium from a hard-copy magazine, and I may as well let it take me where it will. Should I receive some compelling advice, criticism or instruction on this, I'll reconsider my position.
Another thing I've noticed is that I may be looking like a shill for various makers of tools and materials. I touched on this in my first post, but let me restate it. I've read a lot of magazine articles that were vague on details of what exactly it was that was used to accomplish something or other, and/or where they got it. I don't do vagueness. I write here to impart information. It so happens that Dremel made my hand grinder, and Bennett made the wood veneer tape that works so well for me; credit where it's due.
I may return to this subject now and then. There's more to it than meets the eye.
Thursday, December 31, 2009
Wednesday, December 30, 2009
Parquet Flooring
The title of this post is a bit of a fraud, really. I installed a birch parquet floor once the old-fashioned way -- glue, big drum sander rental, the whole nine yards. I was quite pleased with the outcome, but I've never felt an urge to do another one. I won't be detailing the procedure here.
The point of this post is that I was left with almost an entire ten square foot bundle of the flooring material when I got done, and it turns out that the little parquet bits are incredibly useful in the workshop.
The individual pieces that are factory-assembled into a parquet pattern on a perforated paper backing are each 4 3/4" long, just under 1" wide and just over 5/16" thick. I always have a few of them nearby, and I reach for them often for all sorts of things; as clamp pads, as small cutting boards, as sanding blocks, as backing for a drilled hole to prevent splintering, etc., etc. Here's a view of the material.
One of those serendipitous things that I would never have thought of were it not for the leftover flooring being right at hand.
The point of this post is that I was left with almost an entire ten square foot bundle of the flooring material when I got done, and it turns out that the little parquet bits are incredibly useful in the workshop.
The individual pieces that are factory-assembled into a parquet pattern on a perforated paper backing are each 4 3/4" long, just under 1" wide and just over 5/16" thick. I always have a few of them nearby, and I reach for them often for all sorts of things; as clamp pads, as small cutting boards, as sanding blocks, as backing for a drilled hole to prevent splintering, etc., etc. Here's a view of the material.
One of those serendipitous things that I would never have thought of were it not for the leftover flooring being right at hand.
Tuesday, December 29, 2009
Shim Stock
If you have a job to do like installing a door casing, you'll need to have some shimming material on hand for positioning and plumbing and levelling the components. Tapered cedar shakes are ideal if you can find them. Owing to their wedge shape, two can be slid together to create a variable thickness shim. (For an explanation of shakes/shingles, go here. As for finding suitable ones, I got a bundle of them once at the Home Depot, but that was years ago. They may or may not still carry them.)
Fixed thickness shim stock is also handy. I collect suitable stuff as I spot it. An example is the plywood sides and ends of the little crates that clementine oranges come in. The plywood is 3mm thick, and not bad quality.
The cardboard in much retail packaging is often of excellent quality; very smooth and quite dense. I keep a bin of it in the shop, and toss in good pieces as they turn up.
Shim stock is everywhere, you just have to see it for what it is.
Fixed thickness shim stock is also handy. I collect suitable stuff as I spot it. An example is the plywood sides and ends of the little crates that clementine oranges come in. The plywood is 3mm thick, and not bad quality.
The cardboard in much retail packaging is often of excellent quality; very smooth and quite dense. I keep a bin of it in the shop, and toss in good pieces as they turn up.
Shim stock is everywhere, you just have to see it for what it is.
Sunday, December 27, 2009
A Wee Table Repair
The sorry looking little item pictured is a small, black-lacquered and stencil-embellished table that must be sixty years old if it's a day.My wife was using it for a plant stand and the plant's pot leaked, which did a fine job of ruining the table's top. That was years ago. (I hope my mom's gotten over it by now.) I mean to make a new top for it. I don't have the graphic arts skills to recreate the pattern on the original, so I'll have to settle for a plain, glossy black top. (I also don't want to make a career out of this thing.)
I'll leave the rest of it as is, except to clean away the years of grime that have accumulated while the thing languished in my basement. The finish on the legs and shelf is not in great condition, but I want to retain the piece's 'antiquity', such as it is.
An interesting feature of the table is those little studs you can see at the corners of the shelf. Those are threaded wooden 'screws'. I recall as a boy thinking that they were just the neatest things.
Dismantlement
While disassembling it, I marked each leg's position with respect to the top's skirt in a concealed location with a letter punch. I also marked the shelf's orientation on its underside. The components of an item like this table, even though mass produced, may not be perfectly uniform, and had best go back together exactly as they were originally assembled.
The shelf comes away simply by unscrewing the four wooden screws. Each leg is fastened at its upper end by a flat head screw driven through the skirt's corner bracing from in behind.
Separating the top from its skirt looked a bit daunting. I scored through the paint all around, inside and out where the skirt and the top's underside meet. I took a piece of oak 4x4 to use as a hammering surface and hammered at the top's underside all around, the oak block taking the hammer blows and passing them along without harming the top. The top came away fairly nicely. It had been glued and nailed in place. Thankfully, the gluing job wasn't the best. There are places on the upper edge of the skirt that will have to have adhered splinters trimmed away, though.
I can see now how the top was made. It's solid wood, just over 5/16" thick. The top surface is covered with a thick sheet of glued-on printed paper. That's how they did the graphics, and that's why the water did so much harm where it got into a crack.
The Skirt
Trimming the adhered splinters from the upper edge of the skirt looked like a tricky thing to do with a chisel; too easy to pull up a splinter from the skirt rails themselves, and difficult to maintain a dead straight result. I rigged the table saw for ripping, and found a length of baseboard footing molding with a very thin upper edge. I set the rip fence so its distance from the saw blade was exactly the width of the molding, plus the original finished width of the skirt rails. I set the saw blade's height to just a little more than was needed. That setup made short work of the task. (The reason for the intervening length of molding between the saw's iron fence and the skirt was that the skirt's corner braces protruded slightly lower than the skirt rails in places. The molding's thin edge got around that by referencing only to the skirt rails themselves and no higher.)
The Top Blank
The closest I can come with material I have on hand is some plywood that's just over 3/8" thick. If I chamfer the underside edges slightly, I can approximate the visual impression of the original top's thickness. I'll have to veneer all the edges with birch. It's impossible otherwise to get a smooth finish on plywood edges.
The plywood is salvaged stuff with a darkly finished hardwood veneer on the face side. I can't make out the species, but it's close-grained and should finish well with careful preparation. The plywood may have been a wall covering, because the back side has evidence of adhesive all over it. The 'sheet' that I have is about 33"x38".
The original top is 11 1/4" square, with the corners lopped off 3/4".
Following is the procedure for obtaining the 11 1/4" square blank:
1) On the bad side, lay out an 11 1/2" square at a good corner of the sheet. One edge will be a dead straight factory edge. That will be my initial reference edge. The other three edges will all be roughly jigsawn edges.
2) With a portable jigsaw, cutting from the bad side to cause no splintering on the good side, make the two cuts required.
3) Put away the jigsaw. I mention this to raise a point about work habits. I know that there are those who can work effectively in the midst of atrocious clutter, but I'm not one of them. Clutter causes my brain to seize up. Consequently, I'm a great believer in the value of putting away things that are no longer needed. There's also a safety consideration to this. The less that you're having to shove stuff aside, the less likely you are to do harm to a tool, to the work itself or to you. Sermon's over.
4) This was a good time for me to get after the adhesive muck on the plywood's bad side with lacquer thinner and a putty knife for a scraper. With virgin material one would be spared this, obviously. This sort of thing is one of the drawbacks of working with scrounged, salvaged material but, hey, the price of it is pretty attractive. Anyway, the lacquer thinner and putty knife worked to quite good effect. The blank is ready for final-sizing.
I should mention before leaving this point that while I was scraping the bad side, I had the good side sitting on a piece of thin rubber anti-slip material for underneath rugs. It keeps the work from sliding around, and protects it from getting scratched by any particles that may find their way underneath. The method is invaluable, too, while you're sanding.
5) If you're not certain of it, check the table saw blade's squareness to the table, and correct it as required. Set the rip fence for just under 11 1/2" from the blade. The reference edge on my blank has a bit of a roundover at the good side, and I want to be rid of that; I want all the edges to end up square and sharp. Hence, this cut will be to create a new reference edge.
6) Good side up; original reference edge against the rip fence; make the cut. I now have my new reference edge.
7) At the workbench, new reference edge against the edge of an 18" aluminum level. The blade of a carpenter's square against the level as well, the square being on top of the blank. Position everything so the tongue of the square is very near one end of the blank. Making certain that the reference edge and the square's blade are simultaneously held firmly against the edge of the level, draw a line along the square's tongue very near the one end of the blank with a sharp pencil. That line delineates what's to become the reference end.
8) With a sharp plane set for a fine cut, plane to the pencil line. Work inward from both ends so as not to cause any splintering. When done, you'll have a reference end squared to the new reference edge.
If you're familiar with table saw cross-cut sleds, you know that there is a way to not have to do the previous two steps. I don't have a cross-cut sled, so I had to fall back on this method.
9) Set the saw's rip fence for the final, 11 1/4" width of cut. Make a cut with the new reference edge against the rip fence. That gets rid of the original reference edge with the slight roundover. Make the next cut with the reference end against the rip fence. That gets rid of the remaining jigsawn end. We have our square blank.
Cutting Corners
Years ago, I built an oak fern stand with an octagonal top and base. As is the case here, the top and base started out as square blanks. To lop off the corners, I constructed a sled for the table saw that presented the square blanks to the saw blade at a forty-five degree angle, the sled's left edge referencing the rip fence. (I always work with my saw's rip fence to the left of the blade.)
That sled is exactly what I need for this table top, and lo and behold, I found it.
(I never said it was pretty.)[I suppose I should insert the obligatory words about table saw safety here before the safety police have a shrieking fit.
My saw has no blade guard, and I wouldn't install it if it did have one. I've always figured that if I can see the blade, I can avoid the blade. It's worked out for me so far, and this saw has cut a lot of wood. I will emphasize this, though: Think through every cut before you make it, and during every moment that the blade is spinning, your absolutely undivided attention must be on it and on your relationship to it. And don't even think about ever making a cut without wearing eye protection. 'Nuff said.]
So, we're just about set to lop off the four corners. Mark the cut's location for one of the corners, place the blank in the sled and set the rip fence empirically by referencing the saw blade to the mark. Three brief cautions:
a) Be absolutely certain of the blank's fit in the sled. Watch that no splinters or particles get between the blank and the sled's cleats.
b) Be mindful that the sled is always fully and truly registered against the rip fence.
c) Splintering as the blade exits the cut is very likely, especially at the two corners where the good side's grain direction is angled toward the oncoming teeth of the blade. A way to preclude splintering is to keep a small block of softwood pressed against the blank's edge where the saw blade will exit the cut. This slightly complicates the operation, but it can be safely done. Think it through and rehearse it first.
With all that in mind and set to go, we make four cuts and it's done, like so. [I know it looks somewhat rectangular instead of square. It's the camera angle. Trust me, it's square.]
Edge VeneeringI've had good results from a product known as Bennett Preglued Veneer Edging -- Iron-On. I can't seem to locate Bennett on the internet, though, so they may no longer be with us. Someone must still make the stuff.
It's a 13/16" wide, real wood veneer tape with hot-melt adhesive pre-applied to the back. It works as advertised, though I've never applied it to edges this narrow before.
I'll be using birch for this. Birch is a lovely, pale, close-grained hardwood that will give me the smooth surface I want for under an enamel coating. You'll want the blank's edges to be absolutely free of dust beforehand, and the best way to get that is by blowing them off with a compressed air blow-gun. I'll veneer the short edges at the corners first.
I have a retired steam-iron that I use for a heat source for applying the veneer tape. It's kept set at near its high setting. Always cut the tape pieces about 1/2" over-length; a pair of light tin snips cut it nicely. Set a piece of tape in place and press the iron down on it squarely. Heat it till you can see that the glue is going molten. Take away the iron and press down on the tape squarely and firmly with a smooth sanding block. Keep pressing for about 10 seconds to ensure a sound bond.
When you take away the sanding block and examine the job, you should see no evidence of any voids in the bond at its edges.
To trim the tape, you'll need a sharp block plane set for a fine cut, and a small, sharp utility knife (I use an Olfa Model 180). You'll also need something to serve as a cutting block, and some 150-grit aluminum oxide sandpaper.
With the veneered edge hanging out over the edge of your workbench, trim down one side of the veneer with the block plane. Stop just before it's flush with the surface. Do the same on the other side. Trim the ends by pressing the veneered edge firmly down onto a cutting block surface, and running the point of the utility knife over the tape's underside repeatedly until it cuts through. (The forty-five degree angle complicates this a bit. It's much easier to do this at ninety-degree corners.) Sand the edges and ends flush. It's ok to use an orbital power sander for sanding the edges. When properly applied, the veneer is absolutely secure. The ends must be sanded by hand with a small sanding block.
Do the preceding steps at the three remaining short edges. Repeat for the long edges. Long edges are a two-handed job. I start with the iron from the right, moving fairly quickly to the left just to get the tape 'tacked' in place. I then slowly move the iron along from left to right, following along with the sanding block in my left hand. When you're all done, it will look like this.
The image doesn't do it justice, but I hope it gives you some idea of why I think quite highly of this veneer tape.There's still much to be done. I'll update this post as I make progress.
- - -
SATURDAY, JANUARY 9, 2010
There was some unavoidable splintering at the underside when I did the sawing. I've filled that and sanded it. I had thought of chamfering the underside edges to create the illusion of identical thickness to the original top, but I've thought better of it. The extra 1/16" thickness of this top is not disproportionate, and I'd be begging for trouble were I to go ahead with the chamfering idea. So, the next thing up is --
Top/Skirt Attachment
The original attachment method of glue and nails is not on. I need an entirely mechanical fastening method. The skirt is just shy of 1 7/16" high. I'm going to use eight No. 6 x 1 1/2" round head wood screws, two at each corner brace. By counterboring 1/4" deep for the screw heads, I'll get almost 5/16" of effective screw projection into the top, and the screw heads will be hidden. With eight screws, the security of attachment will be adequate, in spite of the very short screw engagement with the top. Pictured is a view of one corner's screw hole layout.
(The masking tape is concealing the 5/8" square mortise that accepts the top end of a leg.) I wanted to point out the usefulness of masking tape as a layout aid. I use it for this sort of purpose a lot. Whenever you have a surface that's difficult to mark or that lacks contrast for a pencil mark, or that you don't want to mark on directly, apply masking tape and you're away.Now I need to drill through eight places 9/64" diameter; clearance diameter for a No. 6 screw. Then I'll counterbore 17/64" diameter to a depth of 1/4".
- - -
Done. Now I have to install all eight screws to the point where their points are just about to emerge from the top of the skirt, position the skirt squarely on the top's underside, hold it firmly in place and tap each screwhead to mark its spot. Before taking away the skirt, I'll want to key the skirt to the top with a letter punch. On an assembly like this, there's no way it's going to fit together any other way than that established at first assembly.
With the eight pilot hole locations marked, I'll chuck a 3/32" twist drill in the drill press and set the depth stop for about 1/16" from the drill press's table surface. Eight pilot holes later I'll put it together.
And here it is. One screw at the lower right hasn't been run in all the way yet.That turned out well, but if I can digress for a bit, I should mention that few things in the workshop are so fraught with peril as axial dimensioning; blind holes and counterbore depths being just two examples. Be it in woodworking or machine shop work, few things are so easy to miscalculate or err in the execution of than axial dimensions. I've even seen an example of the problem in mass produced high-tech equipment. There's a model-line of Hewlett-Packard laser printers that has a design flaw that can become troublesome as normal wear-and-tear progresses. There's a place in the machines where a pair of gears exhibit marginal mesh, even in new machines. Eventually, the gears begin jumping out of mesh. It's an axial dimensioning error that got put into production without ever having been caught. So, axial dimensioning even snags the big guys occasionally. Take great care with it.
SUNDAY, JANUARY 10, 2010
Finish Sanding and Finish Application
I've done the final sanding with 220-grit paper, and 'broken' all the sharp edges; i.e. slightly rounded-over the edges with fine sandpaper. Sharp edges have a way of shrugging off spray paint; surface tension effects cause the paint to back away from sharp outside corners.
Ideally, I'd like to obtain a gloss black enamel finish that exhibits no evidence of wood grain or porosity whatsoever, but I doubt that I'll get that perfectly. I'll start with a liberal coat of grey primer overall. To do that in one go, I've installed four screws in the underside's screw holes. I'll set the piece on its top surface and prime the underside with the screws in it and the edges. Then, using the screws as handles, I'll pick it up and set it back down on the screwheads so I can carry on and prime the top surface. It's a delicate bit of manoeuvring, but it is doable. One is well-advised to rehearse such a sequence beforehand, and make certain that everything needed is at the ready.
I'll give that primer coat a week to harden, and then see if sanding and repriming is called for. I expect it will be.
- - -
SUNDAY, JANUARY 17, 2010
There's nothing like a coat of primer to reveal flaws. There's more grain porosity in evidence than I expected on the top side, and some tiny splintering on the bottom that had escpaed my notice. I've applied Polyfilla to the bottom side flaws, sanded the bottom and the edges and reprimed the bottom and edges. Next week I'll see what I can do about the top side's porosity. Whatever the outcome, I'll settle for it; I would like to have this over with before 2011.
- - -
SUNDAY, JANUARY 24,2010
Two days ago I 'painted' the top side with a thin, overall coating of Polyfilla applied with a putty knife. Today I sanded that. It has had some good effect; I can see where the Polyfilla remains in evidence in the pores. I've just given the top side a heavy coat of primer again, and reprimed the edges. I'll recoat it within an hour, and then I think I'll leave it at that and get on with the gloss black enamel next week.
I know there are products for building a glass-like clear surface on even porous woods. I once saw some small tables in a restaurant or tavern that had been finished that way, to quite a spectacular effect. But I'm not prepared to go to the trouble and expense for this item.
- - -
SUNDAY, JANUARY 31, 2010
'Went to paint the underside with what I had left of a not terribly old spray can of gloss black enamel, and got outrageous orange peel and fish eyes. Wiped it all off, cleaned it with methyl hydrate and tried again with a new can of paint and got fish eyes again on the first few passes. Wiped it off and cleaned it with lacquer thinner. Thankfully, the primer had had a week to harden, so a fast wipe with lacquer thinner didn't harm it. Sprayed it again and it's ok. Recoated it and it's still ok.
I don't know what to make of that fish eyes incident. I know it's said to be asking for trouble when one's painting area shares space with a mechanical shop where there's WD-40 and what have you present, but I'm unaccustomed to having painting trouble like that. Perhaps that's the downside of setting aside a primed item for a week; it has lots of time to pick up airborne contaminants. Anyway, I'll certainly keep in mind the good effect of a lacquer thinner wipe down.
Next up is to paint the top surface and edges.
SUNDAY, JANUARY 31, 2010
'Went to paint the underside with what I had left of a not terribly old spray can of gloss black enamel, and got outrageous orange peel and fish eyes. Wiped it all off, cleaned it with methyl hydrate and tried again with a new can of paint and got fish eyes again on the first few passes. Wiped it off and cleaned it with lacquer thinner. Thankfully, the primer had had a week to harden, so a fast wipe with lacquer thinner didn't harm it. Sprayed it again and it's ok. Recoated it and it's still ok.
I don't know what to make of that fish eyes incident. I know it's said to be asking for trouble when one's painting area shares space with a mechanical shop where there's WD-40 and what have you present, but I'm unaccustomed to having painting trouble like that. Perhaps that's the downside of setting aside a primed item for a week; it has lots of time to pick up airborne contaminants. Anyway, I'll certainly keep in mind the good effect of a lacquer thinner wipe down.
Next up is to paint the top surface and edges.
- - -
SATURDAY, FEBRUARY 6, 2010
Well, it certainly is black. I just gave its top surface and edges two coats of enamel, forty-five minutes apart. 'Looks like it'll be acceptable, if not perfect. What a trying thing that was to paint. (I repeated the lacquer thinner wipe down beforehand, and had no trouble with fish eyes.)
I've cleaned all the other components with Fantastic.
I wanted scratchless foot pads for the bottoms of the legs, so I cut four 9/16"x 3/4" rectangles of felt from an old hat, and attached them with double-sided outdoor carpet tape. It's tenacious stuff, and should work fine here where it will only be subjected to a straight down static load. I wouldn't use the same method on a chair or stool, though. A seated person is seldom a static load. People adjust their position and fidget and squirm, generating all manner of force vectors on the legs of a chair. The flexible adhesive provided by carpet tape will tend to yield to sideways forces and creep out of position, if not creep off entirely.
Anyway, it's done except for final reassembly. I'll stash the newly painted top in a safe place for a week to harden.
SUNDAY, FEBRUARY 14, 2010
Done at Last
And just in time for Valentine's Day. You'd think I knew what I was doing.
Not perfect but not too bad, if I do say so myself. The plain black top is probably an improvement on the rather 'busy' original.
The felt 'feet' were a nice touch. I gave the top a coat of paste wax, which may not have been such a great idea; that stuff can be awfully difficult to buff to a truly streakless condition. Anyway it's as good as it's going to get.
SATURDAY, FEBRUARY 6, 2010
Well, it certainly is black. I just gave its top surface and edges two coats of enamel, forty-five minutes apart. 'Looks like it'll be acceptable, if not perfect. What a trying thing that was to paint. (I repeated the lacquer thinner wipe down beforehand, and had no trouble with fish eyes.)
I've cleaned all the other components with Fantastic.
I wanted scratchless foot pads for the bottoms of the legs, so I cut four 9/16"x 3/4" rectangles of felt from an old hat, and attached them with double-sided outdoor carpet tape. It's tenacious stuff, and should work fine here where it will only be subjected to a straight down static load. I wouldn't use the same method on a chair or stool, though. A seated person is seldom a static load. People adjust their position and fidget and squirm, generating all manner of force vectors on the legs of a chair. The flexible adhesive provided by carpet tape will tend to yield to sideways forces and creep out of position, if not creep off entirely.
Anyway, it's done except for final reassembly. I'll stash the newly painted top in a safe place for a week to harden.
- - -
SUNDAY, FEBRUARY 14, 2010
Done at Last
And just in time for Valentine's Day. You'd think I knew what I was doing.Not perfect but not too bad, if I do say so myself. The plain black top is probably an improvement on the rather 'busy' original.
The felt 'feet' were a nice touch. I gave the top a coat of paste wax, which may not have been such a great idea; that stuff can be awfully difficult to buff to a truly streakless condition. Anyway it's as good as it's going to get.
Saturday, December 26, 2009
Skill vs. Ineptitude
Skill and ineptitude are two sides of the same coin, really.
A great deal of what we commonly refer to as 'skill' is actually just focused patience. Conversely, a great deal of ineptitude results from needless, thoughtless hurry and impatience.
To work skilfully, one must bear in mind that inanimate tools, materials and machine components cannot be willed to behave as we'd like them to. A plane that's set for too thick a cut will not take a fine shaving because one wants it to. The plane must be adjusted. If the blade is dull as well as misadjusted, the plane must be dismantled, its blade ground and honed, reassembled and adjusted. There's no way around that. A motor's armature winding won't fend off damage from a clumsily wielded screwdriver. One's movements must be thoughtful, purposeful, economical and graceful.
I'm largely self-taught in the various areas I work in, and I've been striving lately to come to grips with my shortcomings, and cultivate a much needed maturity in my work. I find myself too often guilty of little bouts of ineptitude, and I never much like the outcome of those. I can distinguish three major sources of the problem.
a) My own nature: a tendency to want things done, but not always to be prepared to put out the tedious effort that may be called for. That's for me to work on, every minute that I'm in the workshop.
b) Workplace conditioning: the whole 'time is money' ethos of capitalism has its witless effect. Bleep capitalism. I'm through with heeding its bogus urgency.
c) Social conditioning; the cultural baggage we all carry that tells us that manual labour has no intellectual component to it; that it's only 'skilled' in the sense that through repetition, the tradesman acquires mastery of his trade, a process not unlike a dog's being trained to sit and heel. That's one of the biggest frauds of all time, initiated and perpetuated by the parasitic classes in an attempt to put an intellectual gloss on their jotting of ledgers and crafting of con jobs.
Skill is not so much an attribute as it is a state of mind. Skill is serenity -- an utter detachment from the world's noise, and an intimate connection with the task at hand.
A great deal of what we commonly refer to as 'skill' is actually just focused patience. Conversely, a great deal of ineptitude results from needless, thoughtless hurry and impatience.
To work skilfully, one must bear in mind that inanimate tools, materials and machine components cannot be willed to behave as we'd like them to. A plane that's set for too thick a cut will not take a fine shaving because one wants it to. The plane must be adjusted. If the blade is dull as well as misadjusted, the plane must be dismantled, its blade ground and honed, reassembled and adjusted. There's no way around that. A motor's armature winding won't fend off damage from a clumsily wielded screwdriver. One's movements must be thoughtful, purposeful, economical and graceful.
I'm largely self-taught in the various areas I work in, and I've been striving lately to come to grips with my shortcomings, and cultivate a much needed maturity in my work. I find myself too often guilty of little bouts of ineptitude, and I never much like the outcome of those. I can distinguish three major sources of the problem.
a) My own nature: a tendency to want things done, but not always to be prepared to put out the tedious effort that may be called for. That's for me to work on, every minute that I'm in the workshop.
b) Workplace conditioning: the whole 'time is money' ethos of capitalism has its witless effect. Bleep capitalism. I'm through with heeding its bogus urgency.
c) Social conditioning; the cultural baggage we all carry that tells us that manual labour has no intellectual component to it; that it's only 'skilled' in the sense that through repetition, the tradesman acquires mastery of his trade, a process not unlike a dog's being trained to sit and heel. That's one of the biggest frauds of all time, initiated and perpetuated by the parasitic classes in an attempt to put an intellectual gloss on their jotting of ledgers and crafting of con jobs.
Skill is not so much an attribute as it is a state of mind. Skill is serenity -- an utter detachment from the world's noise, and an intimate connection with the task at hand.
Thursday, December 24, 2009
Something a Little Different
Pictured is a piece of garment industry equipment that I found by the side of the road. It was made by the Rau Fastener Company of Providence, Rhode Island. 'Could be as old as WWII or even older.In its day, Rau was known for the KLIKIT snap fastener. This machine may have been for installing them. Needless to say, there were no dies with it to give me more clues about its intended application.
Rau was acquired by an outfit name of Scovill in the early 1990s, and it's pretty much faded into obscurity since. It seems that Rau's old facility in Providence is being redeveloped into lofts.
The machine is one heavy, sturdy piece of gear; Rau didn't scrimp on the cast iron and steel. The stand's top is a steel plate over 3/8" thick. The ram and its bore are still in fine condition, but there's quite a bit of slop in the lever's pivot. There's no grease fitting, and drops of oil were no doubt few and far between over the machine's period of service. I'll have to look into that and correct it.
I should be able to fabricate or adapt dies for it for swaging metal eyelets/grommets. I'll have the most awesome eyelet/grommet tool in Canada.
I'll update this post as I make progress.
THURSDAY, DECEMBER 31, 2009
The Lever Pivot
It's a steel pin that's supposed to be secured by a cotter pin on the side you can't see in the photo. Instead of a cotter pin, though, there's a folded-over steel screw in the hole. The Dremel hand grinder with a cut-off wheel in it made short work of that. I set a block of wood under the ram so it wouldn't drop when I took away the lever, got a good grip on the lever and pulled the pin -- easy.
The pin is 3/8" diameter x 2 1/2" long, and in remarkably good condition still. There is some wear, but it's an item that will be easy to fabricate a replacement for, should I choose to replace it.
The holes through the lever-supporting yoke are a bit oval, but they're not in too bad condition.
The hole through the cast iron lever is a sight. It's a real oval, about 3/64" longer than wide. That's where the bulk of the slop is from. I'm a bit surprised that Rau didn't see fit to make this hole oversize, and install a bronze, replaceable sleeve in it. Cast iron is not great as a rotation-bearing material.
Anyway, next up is to dismantle the ram and get everything degreased. I'll want to look closely at the ram's provision for accepting dies, and record all the pertinent dimensions. Most of all I need to ponder how I'm going to correct that oval hole in the lever and get it sleeved.
FRIDAY, JANUARY 1, 2010
Ram Removal
1) Upper Die-Retaining Setscrew (at the lower end of the ram)
>1/4"-20 x 3/8" square headed screw, 1/4" A/F.
>'Looks original. 'Still in fine condition except for a bit of mashing at its end, where it pressed on the die's retaining stem.
2) Ram Restraint Screw
>5/16"-18 x 3/4" dog point setscrew, 5/32" hex socket w/1/2" A/F jam nut.
>'Looks original. 'Still in fine condition.
>This screw's dog point rides in a milled channel in the ram to keep the ram from turning. (There's a nice chart of inch dog point dimensions here.)
3) Ram
>Something's stopping the ram from lifting out of its bore as it should now; possibly a burr at the threaded hole for the die-retaining setscrew. 'Time to get the casting off its stand and over to the workbench for a closer look. Four 1/4"-20 screws w/split lockwashers and hex nuts are the fasteners.
>That was it; a burr at the setscrew's thread. 'Filed it a bit and out it came.
>The ram is 1" diameter, 7" long and in virtually flawless condition. There's just a bit of surface rust on the exposed areas that weren't inside the bore. Here's a photo of it.
The wide channel at the upper end goes all the way through. It's where the tip of the lever engages the ram to raise and lower it.
The bottom end is bored 3/8" diameter, 1" deep to accept the stem of a die.
I'll gently brush the rust with a wire wheel. Aside from that, this item needs nothing done to it.
Next up is to degrease the casting.
- - -
There, that's done. It was a bit of a challenge for my little five-gallon parts washer.
I neglected to mention the lower die-retaining setscrew in the base. It's the same as the upper one except that it's 1" long. It's also in fine shape and looks original.
I was able to wire brush the machined upper surface of the ram bore casting, and the deck for the lower die. The iron came up bright and pretty in no time. I immediately applied mineral oil to the machined surfaces and the bore to preclude rusting. Here it is.
There, that's done. It was a bit of a challenge for my little five-gallon parts washer.
I neglected to mention the lower die-retaining setscrew in the base. It's the same as the upper one except that it's 1" long. It's also in fine shape and looks original.
I was able to wire brush the machined upper surface of the ram bore casting, and the deck for the lower die. The iron came up bright and pretty in no time. I immediately applied mineral oil to the machined surfaces and the bore to preclude rusting. Here it is.
Lever Pivot Holes Sleeving
It's time to get serious about how to go about this.
I'd really like to get as much of the slop as possible out of the lever's action. That means boring and sleeving the three holes involved, and that's fraught with peril. Ideally, the boring ought to done on a big milling machine where the yoke and the lever could be set up so their holes are perfectly co-axial with the milling machine's spindle, and then bored through for sleeves. The hole through the lever is particularly critical; it must end up perpendicular to the long centreline of the lever, else the lever will hang crookedly in its yoke.
The other consideration is sleeve material. Given my shop's capabilities, I'm limited to using thin-walled hard brass tubing -- the type that's available from hobby shops. The stuff I'm familiar with in my area is made by K&S Engineering of Chicago, Illinois. (Here's their website for what it's worth, which is not much.) The diameters start at 1/16" and go up in 1/32" increments to 21/32" (Each successive size 'telescopes' over the next smaller size.)
Ordinarily, brass is not considered a sleeve bearing material, but it'll serve here. In any mechanism, lubrication is crucial, and if kept properly lubricated, a brass sleeve bearing for a steel pin will work fine.
I'll start with the yoke as it will be the easier item to deal with. The holes aren't so far gone, and I'll only need a single 13/32" sleeve in each hole. I'll drill through in two stages; 25/64" followed by 13/32".
- - -
Well, that was scary enough. I was taking a bit of a chance with drills that size in cast iron with a hand-held drill; the drills want to 'bite' quite aggressively and it's difficult to control the operation. (I should mention that I had the casting securely clamped to the workbench while I was drilling. All heck would have broken loose had I not.) Unsurprisingly, I got a somewhat bell-mouthed result where the drills entered, but it's going to work out ok. The opposite yoke hole where the drill had guidance from the entry point yoke hole turned out a tiny bit undersize. That's actually normal for twist drills; twist drills are not reamers. Whenever you're enlarging a hole only slightly with a twist drill, expect to get a slightly undersize result; it's the nature of the things. (I think I understand the effect. Someday I might get around to confirming that I do understand it and writing a proper explanation of it.) In any event, the hole is not so undersize that I can't push the tubing in.
I have a Loctite retaining compound known as RC/609 on hand. It's a variant of their thread locker products that's for situations just like this one, where a cylindrical fit needs to have a few thou taken up. Loctite claims it will fill up to 0.005".
What I'm going to do here is install a single length of tubing right through the yoke casting, with all the interfaces smeared with the RC/609. Tomorrow, the compound will have fully cured and I can saw away the superfluous tubing and file the sleeves' ends flush. (RC/609 cures fully in six hours at room temperature, but it 'fixtures' quickly, i.e. it 'tacks' and resists hand adjustment of the parts. On an installation like this, you need to have everything thought out and rehearsed before you begin the actual work. A slip up can cost you dearly in wasted time and material, should you have to hammer things apart and start over.)
- - -
Here's the casting with the tubing installed.
The bell-mouth effect at the hole's entry point is still in evidence; the RC/609 couldn't fill all of that. I'll use CA adhesive to fill the crevice before I cut off the tube. There are a few notes on CA adhesive here.SATURDAY, JANUARY 2, 2010
Lever Pivot Hole
The lever is an unwieldy thing; to prop it up so it could be drilled on the drill press would be an aggravating challenge, and it would still be very difficult to assure the part's long centreline perpendicularity with the drill's axis.
I'll clamp the lever in my wood vise, and fabricate a drill guide block that I can clamp to the lever at the site of the oval hole.
- - -
I've taken a length of oak 1x3, cut it in half and glued the two pieces together to give me a solid block that's about 4" x 2 1/2" x 1 1/2". I'll drill through that 7/16" diameter on the drill press, and I'll have a reasonably accurate drilling guide. (I'll clamp the block to the drill press's table for this. Oak's spectacular grain exhibits equally spectacular density variations that make it a tricky material to machine. Drills and saw blades are prone to deflect as they seek the path of least resistance.)
- - -
Now I need a way to align the guide block's hole with the hole in the lever. I took a 2 1/2" length of 7/16" dowel and chucked it in the wood lathe. The lever's thickness at the pivot hole area is about 9/16", so I turned down about 5/8" of the dowel's one end to 3/8" diameter, and that gave me an alignment pin. In the photo below you can see the guide block clamped in place with the alignment pin still in it.
I've tightened that clamp for all that the clamp and I are are worth, knocked out the pin and I've got my drilling setup.
- - -
It worked quite well; all done in one go with the 7/16" twist drill. I'll just reiterate here that drills this size in a material like cast iron have a tendency to really 'bite' and stall. Go very easy on your rate of feed.
Next up is to cut away the superfluous tubing from the yoke casting and dress the rough ends of the resulting sleeves. Then I can prepare the two sleeving pieces that I need for the lever.
SUNDAY, JANUARY 3, 2010
Cutting Away the Tubing
Clamp the casting in place at the front of the workbench. You'll want the finest-toothed saw blade that you've got; 32 TPI is barely fine enough for the thin-walled tubing.
The outboard cut is easy to start. The two inboard cuts are a little bit tricky. You want to start the cuts very near to the casting so as to minimize the amount of filing required, but you don't want the saw's teeth scraping the casting. Use a business card as a spacing shim for starting each cut. The method is not fool proof, but it gives a better result than just running the saw down flush with the casting,
A sharp 1" wide mill file works well for filing the sleeve ends flush. For deburring, I keep a dull No.11 X-Acto knife handy by the drill press. It's quite versatile as a deburring tool, and will work well here.
There; the yoke casting is sleeved. The pivot pin's fit is much improved.
Lever Hole Sleeving
This sleeve will be just under 9/16" long, and made of two pieces of tubing; one 7/16" diameter and one 13/32" diameter.
For the smaller diameter one, I can use the bit that I sawed out from between the casting's ears (nothing goes to waste around here). I've trimmed one end of it on the lathe, and installed it in one end of a full 12" length of 7/16" tubing with RC/609. (I've left it on top of the furnace to hasten the retaining compound's cure.)
Once cured, I'll chuck it in the lathe and retrim the end to be certain that the two components are flush with one another. Then I'll part off the length I need and deburr it. I'll be ready for a trial assembly.
- - -
Done. The trial assembly proved good, which is to say that the hardwood guide block for the drilling operation worked perfectly. I've done the final sleeve installation with RC/609. Here's a photo of it.
A pretty much flawless outcome, if I do say so myself. RC/609 breaks down entirely at 250 degrees C/482 degrees F. A propane torch would be adequate to achieve that, so should the need ever arise, that sleeve could be punched out and replaced.
- - -
SUNDAY, JANUARY 10, 2010
The Pivot Pin
The original pivot pin is not unfit for use, but it does exhibit some wear so I'll replace it.
A 3 1/2", 3/8"-16 SAE grade 5 bolt has an unthreaded shank almost 2 1/2" long, so if I drill one for a cotter pin and cut off the threaded end, I'll have a new pin. And I've just raised a bunch of tangential points here.
First thing; SAE stands for Society of Automotive Engineers. (They're now known as SAE International.) To grossly oversimplify, just think of them as the arbiters of all things 'inch' in mechanical engineering, at least in North America.
As for 'grade 5 bolt', there's a chart of SAE bolt head markings and their meanings here. Grades 1 & 2, 5 and 8 are the most commonly encountered and readily available ones. Grade 5 should be adequate for my pivot pin, and it's not so hard that it can't be readily sawn and drilled.
Replacing a dome-headed pin with a hex-headed one raises the issue of 'purity' of machine restoration. While I'm sympathetic to considerations of purity, I'm not a purist when restoring a piece of gear to usable condition; the time and resources that 'pure' restoration require are out of this world. Were I restoring some incredibly valuable antique automobile or the like, I might be a purist about it, but not for gear such as this. Also, I find that I can often make small but not insignificant improvements to equipment that its original designer/manufacturer overlooked, either out of ignorance, or out of production cost constraints that I'm not encumbered by on a single unit.
Ok, enough of that. I believe I was about to drill and cut a bolt to make a pin. Here's a photo of the drill press vise setup for the drilling operation. (The vise's fixed jaw is grooved for this sort of thing.)
The far side bolt is there to balance out the vise screw's force on the sliding jaw. The square is there to give me a perimeter reference for positioning my centre punch mark. For a 3/8" diameter bolt, I need to have the punch mark 3/16" from the square's vertical blade-edge; then I'll have the punch mark centred up at the top of the bolt's circumference so the drill will start and go clear through the centre of the bolt as it should. I'll start with a 3/32" drill, and then finish off with a 1/8" drill.With that done, I can saw off the bolt's threaded portion, square off the sawn end and chamfer it in the lathe and I'll have my pin.
- - -
Done. 'Nearly ready for final reassembly, but there remains the matter of washers to take up the difference between the 9/16" thickness of the lever at its pivot point area, and the 3/4" gap that it resides in. The difference is 3/16". Half of that (for equal space on either side of the lever) is 3/32". And it turns out that I have on hand some 5/16" common plate washers with a 3/8" inside diameter that are exactly 3/32" thick. They just need a bit of lapping on abrasive paper to smooth their 'burry' sides. (I keep a fairly good supply of common hardware in the shop. It saves me shopping trips and aggravation when I have enough of just what I need right at hand.)
(Plate washers or bolt-size washers are flat washers meant for rough-and-ready construction as in picnic tables and the like assembled with carriage bolts. The washers from 1/4" to 1" all have inside diameters 1/16" greater than their nominal size. Hence, a 5/16" washer has a 3/8" inside diameter. As happened here, that sizing rule can be put to good effect when a very close-fitting washer is needed. SAE flat washers are meant for use in machinery, and are sized for a closer fit on bolts. A 5/16" SAE washer has an inside diameter of 11/32", but for my purpose here, the 5/16" plate washers were ideal.)
- - -
Final reassembly is done. What a beastly thing that machine is to manipulate. There was no doing it with the casting on its stand. It had to be done horizontally on the workbench. After much shimming and positioning, I got it together with wheel bearing grease smeared in the pivot bore and on the pin. Back on the stand, the lever's action is now as it ought to be; when the ram meets resistance, there's no lost motion of the lever as it takes up slop -- there's no slop to take up.
- - -
SUNDAY, JANUARY 24, 2010
The Stand
Since I'm not doing a full blown restoration here, I'm not going to repaint the stand. But the top surface on either side of where the machine sits is rusty, and could soil material that contacts it while at the press, so I'll repaint the top for the sake of a clean work surface.
I happen to have a spray can of blue that looks like it might be reasonably close to the original shade. If I didn't have that, I'd probably go with light grey as an unobjectionable contrast colour.
- - -
SUNDAY, FEBRUARY 7, 2010
I've cleaned up the stand's leg assemblies, and painted the top's top surface and edges. (Per my usual routine of one coat of primer, two coats of enamel, each successive coat applied within an hour of the previous one. I get excellent results from that method.) That actually turned out better than I expected it to. I sanded the top but didn't strip what paint there was entirely. There's a danger when you repaint such a surface that the powerful solvents in spray paint will soften and lift the edges of the patches of original paint. I got almost none of that; the thing looks pretty decent -- entirely good enough for my purposes here. I'll give it time for the paint to harden and then reassemble it all.
While I was cleaning the leg assemblies, I discovered some Canadian content. On the inside of the angle-iron legs there's embossed the word "CANADA".
As for finding dies for it, good luck. I've googled 'rau press dies' and only gotten obituaries for people with the name "Rau". I tried E-bay and came up with nothing. I appear to have one of the most obscure pieces of gear on the planet here.
- - -
Update -- SATURDAY, NOVEMBER 22, 2014
I ended up selling part of the machine (the pedal/lever) to a company in British Columbia that had had one break on them. I scrapped the rest of the machine. The stand I kept -- it's now the stand for an antique grinder.
Sunday, December 20, 2009
Poulan 1420 Electric Chain Saw Overhaul
The big boss where I work is an ace firewood scrounger. He's used the subject machine for several years in his garage for cutting up lengths of hardwood logs that he comes across. The saw started making some grotesque noises awhile ago. He bought himself a new one and brought me the casualty to look into.
I took it apart and found a curious failure. The motor bearing at the business end of the motor (the end with the drive gear on it) was still in good condition, but the bearing at the commutator end had failed catastrophically -- to the point where it had spilled its balls. One would expect it to have gone the other way 'round. The business end bearing is the one with all the stress on it; the commutator end bearing is pretty much just along for the ride. It may be that the commutator end bearing is more vulnerable to airborne particulate contamination; the business end bearing is more sheltered
Following is a detailed teardown and overhaul procedure.
Teardown
[I don't write teardown procedures as linear exposition. I find that approach unhelpful and eye-glazing. What follows is a list of each item to be removed or dealt with in order, along with any and all information pertinent to each item. I normally use 'bullets' as sub-item leads, but I can't do that the way I'd like to here; Blogger's text entry apparatus is not a full-blown word processor by any stretch of the imagination. Instead I'll use the character '>'.]
Notes:
>'A/F' = 'Across Flats'; i.e the span of a hex nut.
>'w/' = 'with'.
>All screws are No. 2 Phillips recess.
1) Chain Drive Side Cover
>One No. 10 x 1 3/4" black pan head threading screw at the lower front. Note that there's a rolled steel spacer associated with this screw. It will be free to fall out when the cover is removed. The spacer is 1" long, 1/4" I.D., 3/8" O.D.
>Seven No. 10 x 3/4" black pan head threading screws.)
2) Chain Bar Clamp Plate and Bar/Chain
>Two 5/16" - 18, 1/2" A/F hex nuts w/integral washers.
3) Chain Tension Adjuster
>Lift it out. It's an 8-32 x 1 3/8" round head screw with a 1/2" square washer under its head, and a travelling, female-threaded steel 'finger' that engages the chain bar. The screw's end has been purposely 'distressed' so the travelling 'finger' can't be removed.
4) Gearbox Cover
>One No. 10 x 3/4" black pan head threading screw at the cover's rear, and then it just lifts off..
5) Switch
>The interlock button is a little snapped-in plunger. Pry it out, then the switch can come away from the frame.
6) Bar Oil Reservoir
>Lift it out. There's no fastener.
7) Large-Gear/Chain-Sprocket
>One 5/16" - 18, 1/2" A/F hex nut w/integral washer.
>One 5/16" fender washer, 1 3/16" O.D.
>The item just slips off its spindle. It has a combination sleeve bearing and needle roller bearing in its bore. The sleeve bearing portion supports the large gear at the inboard end. The needle roller bearing supports the chain sprocket at the outboard end. The gear is some sort of plastic material.
8) Motor Assembly
>Five No. 10 x 3/4" black pan head threading screws.
>The assembly is pulled straight out.
>The motor is a Johnson Motor No. U-9832.
And there we are. We have the motor out. Now the real fun can start.
Needless to say, every item listed above was filthy with greasy sawdust and needs cleaning. Now, prior to dismantling the motor, is a good time to do that. All the cleaned stuff can go in a bin and be set aside out of harm's way. I'll have my bench clear for the work on the motor.
Motor Teardown
A word of caution: Armature and field windings are easily damaged. Exercise great care when dismantling and handling motor components. A split-second's carelessness can cost you the motor.
Another word of caution: Before taking something like this apart, it's a good idea to mark components' relationships to one another. An electric engraving tool is most helpful here. Also, a centre punch can be used to produce permanent alignment/orientation marks. Take care to make your markings unambiguous. Axial dimensions should be measured and recorded; things like shaft protrusion lengths can turn out to have a bit of variability at reassembly, and it's good to have a record of the original, factory dimension.
1) Switch/Linecord
>The two motor leads have to be disconnected to free this item from the motor. The switch's wiring terminals are the 'push-in' type. By poking the shank of a 1/16" twist drill in alongside a wire, you can deflect the terminals' springy contact and release the wire with no harm done to the contact.
2) Pinion Gear
>There's a small external snap-ring at the end of the shaft, suggesting that the gear should just slip off the shaft once the snap-ring is removed. From what I've seen of most readily available snap-ring pliers, pliers with small enough tips to fit a snap-ring this size are not so easy to come by. I solved this problem for myself years ago by filing the tips of a pair of snap-ring pliers to fit small rings. You may have to do the same. It's a painstaking bit of work, but quite doable.
>With the snap-ring off, the gear proved to be stuck on the shaft. There wasn't space to get a puller on it, and prying with a screwdriver didn't work. And what there is to pry against is the plastic end-frame of the motor, which limits how forcefully one dares to pry. As I was rummaging through my drawer full of pullers, I came across a vehicle door trim remover that I'd bought long ago and all but forgotten that I had. I tried it on the gear, and it turned out to be the perfect pry bar for the job. It provided sufficient leverage while doing no harm to the plastic end-frame.
>One can expect to run across this sort of snag on old machinery. All it takes to make a slip fit an obstinate fit is a tiny bit of rust or sticky fouling on a shaft or in a bore.
3) Cooling Fan
>Another snag. The cooling fan is a plastic disc with twelve straight, centrifugal blades on it. Its means of attachment to the shaft wasn't obvious. It didn't appear to be threaded, though I tried twisting it in both directions -- to no avail. That left pulling it off, but I could see no way of applying a puller that wouldn't damage the part. With a 1/16" twist drill, I drilled the plastic hub directly alongside the shaft at nine places around the shaft to relieve the hub's grip. That worked. I was able to twist and pull the fan off. 'Turns out the fan's bore was pressed onto a finely splined shaft -- a very secure fit indeed. There's still enough left of the fan's bore that the fan should fit back on properly, and at final reassembly I'll fill all the drill holes with epoxy.
>If I had it to do again, I'd try drilling two 11/64" holes through the fan 180 degrees apart so as not to imbalance it at all. I'd get the holes as near to the shaft as possible, where the disc is thicker. Then I'd have a means of installing a couple of 8-32 screws with nuts and rigging a puller.
4) Brushes
>The brush holders and springs were well thought out in this motor. The springs are torsion springs that are easily backed off and moved aside for brush removal. There was a snag, though, in that one of the brushes had overheated and was stuck in its channel. I did some harm to the face of the brush as I pried at it to free it up. Nothing fatal, but not good. I should have sprayed it with WD-40 first; that might have made it easier to nudge the brush loose.
4) Commutator End Frame
>Two No.8 x 2 3/8", 1/4" A/F hex washerhead screws.
>Since the bearing had no balls in it, the end frame came away easily. With the two long screws out, the motor's field winding frame and its other end frame were no longer attached, and I wanted them to be held together until I could get the armature out. I put the screws back in with two 7/8" long, 1/4"-20 coupling nuts under their heads for spacers, to take up the screw length formerly taken up by the commutator end frame.
5) Outer Bearing Race
>This part was a light interference fit in the plastic end frame. I was able to punch it out a little at a time by engaging a small chisel with the groove in the bearing race from the outer side of the end frame.
6) Armature
>Easily pressed out of the remaining plastic end frame on a hydraulic press. There was a wavy washer on the bearing's outer face, presumably to provide a bit of axial preload to the assembly.
7) Business End Bearing
>There was a substantial e-clip on the shaft serving as the bearing's axial position reference/stop. With the e-clip pried off, it was easy to get a small, two-jawed puller on it and pull the bearing off. Prying off the e-clip had to be done carefully so as not to harm the windings.
8) Inner Race of the Commutator End Bearing
>This was tricky because the part was too small to afford any purchase to a puller's jaws. As with the other bearing, there was an e-clip to remove. With the e-clip out of the way, I had just enough room to cut through the race with a small cut-off wheel in the Dremel hand grinder. I did a bit of harm to the shaft's surface, but not enough to have any ill effect on installation of a new bearing.
9) Business End Frame
>'Removed the two screws that I had put back in with spacers in item 4 above.
>I blew off all the greasy sawdust that I could and degreased it in the parts washer. For a follow-up on parts like this, I spray them down liberally with Fantastic and rinse them with scalding hot water while wearing nitrile gloves. Blind screw holes must be blown thoroughly dry before reassembly. Pipe cleaners are helpful as well for drying out blind screw holes.
10) Armature
>'Needs a thorough blow off with compressed air.
>I chucked it in the lathe and burnished the commutator with 600 grit silicon carbide paper, followed by 1200 grit. A jeweller's screwdriver works nicely for scraping the gaps between the segments. Just prior to reinstalling the commutator end frame, I'll wipe it off with lacquer thinner to make certain that it's free of any oily contaminants.
Bearings
Both bearings are the same; they're NSK No. 6900ZZ -- 10mm bore x 22mm O.D. x 6mm width, shielded both sides. I mentioned to the guy at BDI Canada, the bearing distributor, that a sealed version might be in order as a replacement, and he said that sealed bearings are avoided in hot-running applications; the seals will tend to quickly go to ruin. A serious wood cutting session in July would no doubt make for a very warm motor, so I went with a shielded replacement. The BDI fellow tried to find me a less expensive bearing, but it turned out that NSK is the sole source for this particular bearing, so NSK it had to be; $15.80 plus sales taxes. A new saw is about $70.00. Small wonder that the landfills keep filling up, eh?
The one good original bearing spun very freely, which is indicative of a grease-starved bearing. It's possible to pry off a shield on a bearing with relatively little damage to it by shoving the sharp point of a scriber between the shield and the inner race. I did that and, sure enough, the bearing's interior looked like a grease-free zone. I let it sit in the parts washer's solvent for a week, then thoroughly rinsed it and blew it dry. (By the way, it's considered a poor practice to set bearings to spinning with compressed air; you can cause them to spin without lubricant at outrageous speeds by doing that -- not good.)
For a bearing grease, I'm partial to Canadian Tire's "Motomaster" brand "Wheel Bearing & Chassis Lubricant". (My truck's front wheel bearings have been running in it for a couple of years now since I replaced the rotors and bearings.) I'm probably guilty of overfilling the bearing with grease, but I figure that if excess grease seeps out when the thing warms up, no harm can come of it since this bearing will be at the end opposite to the commutator. I reseated the shield by going around its outer edge with Channellocks, gently squeezing its lip back in place. It might be possible to press or punch it back in place, but you'd need an adapter the full diameter of the bearing, and you'd need to get everything set up for a dead square start -- easier said than done.
Motor Reassembly Notes
A 10mm, six-point, deep 1/4" square drive socket served as a pressing tool for pressing the bearings back on the shaft by their inner races, but a bit of modification was called for. As with most socket wrenches, the hex opening of this one was quite severely chamfered inside to make it easy to slip the wrench over a nut. I chucked it in the lathe and with it spinning, applied a small grinding wheel in the Dremel tool to it to grind its end down to where most of the chamfer was gone. That gave me a pressing tool that presented flatly to the face of the bearing's inner race.
I found it easier to get the bearings started squarely by hand with the pressing tool and a plastic-faced mallet, than to start the bearing directly on the hydraulic press. The hydraulic press is a wonderful tool, but some items can be awkward to set up on it, and this was one of them.
The remainder of the work was easy and straightforward. The bearings' outer races are a hand press fit in the plastic end frames.
I drilled the fan in two places, as I'd mentioned earlier that I should have done in the first place. I'll be able to apply a puller now should I ever have to remove it again. I used my woodworking vise as a press for putting the fan back on. It went on squarely and looks like it will hold fine, in spite of the nasty way I went about getting it off. I'll still shove as much epoxy as I can into all the holes I drilled, though.
Motor Bench Test
I clamped the motor securely in the woodworking vise for a trial run. (Don't even think about doing this sort of thing unless you have an absolutely secure way of holding a motor that in no way involves your hands. Eye protection is mandatory. Universal motors have considerable starting torque; the torque reaction at start-up can be startling. Then they run at a no-load speed in excess of 20,000 rpm. They're not an item to be toyed with. See my anecdote "A Cautionary Tale".)
It runs fine, though the commutator sparking looks a bit excessive to me. It's going to have to do; the likelihood of me finding replacement brushes for this motor is slim to nil. Time to reassemble the machine.
Saw Reassembly Notes
Pinion Gear
The pinion gear can go back on the motor's shaft either end first, but it's best in reassembly to get gears back together in the same mesh they've always had. Though the pinion's teeth exhibited no wear to speak of, it was evident which side of the teeth had been in contact with the large gear's teeth, making it easy to determine how to put the gear back on the shaft.
Snap-Ring
I broke the little snap-ring for the pinion gear while trying to correct a bit of distortion in it with pliers; sometimes it's best to leave well enough alone. I have spares on hand, so that caused me no real grief. (Princess Auto puts up assortments of common mechanic's fasteners in compartmented boxes. They're well worth having in the shop.)
Large-Gear/Chain-Sprocket
I packed the large-gear/chain-sprocket's needle roller bearing with wheel bearing grease, and smeared the sleeve bearing and spindle with it as well. Before slipping the item onto it's spindle, I filled its gear teeth with grease. After installing the gear and giving it a few rotations, I took away all the squeezed out grease. For an arrangement like this one, that's as good as it gets for gear lubrication.
Fasteners
All of the casing screws are of the 'threading' variety; i.e they form their own female threads in the plastic when they're first installed at the factory. The type used here do that by displacing and compressing plastic; no plastic material is cut away as with some types of threading screws. It makes for a very sound and strong female thread. At reassembly, it's important to get the screws started correctly so they run back into the original thread and don't start forming another thread; that tends to lead directly to a stripped thread. A way to ensure engagement with the original thread is to present the screw lightly to its hole, then turn it counterclockwise until you feel it drop into the female thread's starting point. The screw should then run in easily.
An interesting feature of the screws used here is that their threads are a double helix; you can see it if you examine the end of a screw closely -- there are two helix starts. (Hence, 'double-start' screw.) I can't really prove this, but I suspect that such screws are prone to have very slight asymmetry between the two helices. The result of that is that a given screw may run back in more easily from one of its starts than from the other; something to be mindful of if you find that a screw is offering more resistance than feels right.
Wiring Lay
Wiring lay can be an aggravating thing to re-establish in portable power tools; there's often very little space for it, and even stranded conductors have enough springiness to make a nuisance of themselves as you try to get them to stay put while you close things up without pinching any wires. This machine was actually pretty good in that regard; plenty of space, and a well thought out wiring lay.
Whenever you're closing up a wiring cavity, and you start to feel a 'squishiness' as you tighten a screw down on what should be a rigid interface, stop. You're pinching a wire. Open it up again and correct the problem.
Chain Tension
Poulan's instruction manual is a bit less than enlightening on this. After explaining the action of the chain tensioner and taking one through to an initial point of tension, one is told to, "Continue turning the adjusting screw until the tension is correct." [!?] One is not told what the criterion for 'correctness' is. I'll go with 'no slack; no tightness'.
Bar Oil
I looked into this and learned that ordinary lubricating oil is not recommended. Chainsaw bar oil is formulated to be sticky so it doesn't get flung off the chain. I went to Canadian Tire for some and it turns out that the stuff is also formulated for cold weather or warm; what they had on the shelf this time of year was marked "Fall/Winter". At least the price is within reason -- $3.49 for a Yankee quart (946 ml).
And Here It Is
I began this post before I'd acquired a camera, so I don't have a 'before' picture; 'Before' would have looked about the same, only grimy.
SUNDAY, JANUARY 31, 2010
'Oiled the chain with a little oiler I made from a ladies' hair colouring goo bottle, filled the oil reservoir and tried it on a 2x4. It runs and cuts.
The bar oiler appears to have ambitions to be an automatic oiler, judging by the puddle it's leaving me when I set the saw down. I'll have to look into that. Wouldn't hurt to sharpen the chain, too, although it's not in too bad shape.
MONDAY, FEBRUARY 15, 2010
The Bar Oiler
The oil reservoir is a flexible plastic 'bottle'. To dispense oil, you press down on its filler cap, which squeezes the thing and forces oil out of its dispensing orifice. It does seep oil out of that orifice when it's sitting idle. There's no check valve of any kind associated with it, so it's not clear to me how it could ever not seep oil. Perhaps when new, the orifice only opens when there's some pressure applied behind it, but age and use have made it leaky.
Poulan's website is quite impressive for providing service parts, but I won't pursue getting a new oil reservoir -- a bit too much of business and commerce for my liking. If I hang the saw by the hole in the nose of its bar when it's not in use, the oil will be down away from the orifice and won't be able to leak out. Whenever the saw is actually in use, the leakage really won't be a bother; problem solved.
The Chain
On closer inspection, I can see that this chain has been resharpened many times, and not uniformly -- some teeth are shorter from front to back than others. If I had more confidence in my motor overhaul, I'd get a new one. As things are, I'll give this one a touch-up sharpening and live with it. I'm actually unlikely to have much use for the saw.
The chain is made by Oregon, which outfit appears to pretty much dominate the industry. As with all things, when you start looking into the subject of saw chain you discover that there's much to learn, not that I really need to know all that much of it to deal with this chain.
This chain appears to be a fairly light duty, very low kickback design. Typically, every other link of a saw chain has a cutter tooth. On this one, every third link has a cutter tooth, the two intervening links are toothless 'bumper' links. This is probably not a chain that a working professional would have any use for -- it's no doubt been specifically designed to be as safe as possible for occasional use by homeowners.
Saw chains are sharpened mounted on the bar. Presumably, the filings fall away and don't pose a great wear hazard to the chain. Here's a photo of a good setup for sharpening:
There's quite an array of sharpening gear available out there, but at bottom all that's really needed is a round file of the correct diameter for the cutting teeth (5/32" in this case). Adherence to the original chisel angle of the teeth, and consistency of tooth length are what one wants to strive for. That's probably easier said than done; the odd tooth may need more filing than others, and so end up getting shortened more. (By 'shortened' I'm referring to front-to-back length of the tooth, not height. Teeth are never filed on their top surface that I'm aware of.)
It's helpful to dab one link with Wite-Out to indicate a start/end point on the chain. I'm inclined to file from a tooth's chisel edge inward, so as not to turn a 'wire edge' on the tooth.
Anyway, this chain is too far gone to be worth fussing over. I've given it a touch-up filing. I'll see what use I find for the machine.
I took it apart and found a curious failure. The motor bearing at the business end of the motor (the end with the drive gear on it) was still in good condition, but the bearing at the commutator end had failed catastrophically -- to the point where it had spilled its balls. One would expect it to have gone the other way 'round. The business end bearing is the one with all the stress on it; the commutator end bearing is pretty much just along for the ride. It may be that the commutator end bearing is more vulnerable to airborne particulate contamination; the business end bearing is more sheltered
Following is a detailed teardown and overhaul procedure.
Teardown
[I don't write teardown procedures as linear exposition. I find that approach unhelpful and eye-glazing. What follows is a list of each item to be removed or dealt with in order, along with any and all information pertinent to each item. I normally use 'bullets' as sub-item leads, but I can't do that the way I'd like to here; Blogger's text entry apparatus is not a full-blown word processor by any stretch of the imagination. Instead I'll use the character '>'.]
Notes:
>'A/F' = 'Across Flats'; i.e the span of a hex nut.
>'w/' = 'with'.
>All screws are No. 2 Phillips recess.
1) Chain Drive Side Cover
>One No. 10 x 1 3/4" black pan head threading screw at the lower front. Note that there's a rolled steel spacer associated with this screw. It will be free to fall out when the cover is removed. The spacer is 1" long, 1/4" I.D., 3/8" O.D.
>Seven No. 10 x 3/4" black pan head threading screws.)
2) Chain Bar Clamp Plate and Bar/Chain
>Two 5/16" - 18, 1/2" A/F hex nuts w/integral washers.
3) Chain Tension Adjuster
>Lift it out. It's an 8-32 x 1 3/8" round head screw with a 1/2" square washer under its head, and a travelling, female-threaded steel 'finger' that engages the chain bar. The screw's end has been purposely 'distressed' so the travelling 'finger' can't be removed.
4) Gearbox Cover
>One No. 10 x 3/4" black pan head threading screw at the cover's rear, and then it just lifts off..
5) Switch
>The interlock button is a little snapped-in plunger. Pry it out, then the switch can come away from the frame.
6) Bar Oil Reservoir
>Lift it out. There's no fastener.
7) Large-Gear/Chain-Sprocket
>One 5/16" - 18, 1/2" A/F hex nut w/integral washer.
>One 5/16" fender washer, 1 3/16" O.D.
>The item just slips off its spindle. It has a combination sleeve bearing and needle roller bearing in its bore. The sleeve bearing portion supports the large gear at the inboard end. The needle roller bearing supports the chain sprocket at the outboard end. The gear is some sort of plastic material.
8) Motor Assembly
>Five No. 10 x 3/4" black pan head threading screws.
>The assembly is pulled straight out.
>The motor is a Johnson Motor No. U-9832.
And there we are. We have the motor out. Now the real fun can start.
Needless to say, every item listed above was filthy with greasy sawdust and needs cleaning. Now, prior to dismantling the motor, is a good time to do that. All the cleaned stuff can go in a bin and be set aside out of harm's way. I'll have my bench clear for the work on the motor.
Motor Teardown
A word of caution: Armature and field windings are easily damaged. Exercise great care when dismantling and handling motor components. A split-second's carelessness can cost you the motor.
Another word of caution: Before taking something like this apart, it's a good idea to mark components' relationships to one another. An electric engraving tool is most helpful here. Also, a centre punch can be used to produce permanent alignment/orientation marks. Take care to make your markings unambiguous. Axial dimensions should be measured and recorded; things like shaft protrusion lengths can turn out to have a bit of variability at reassembly, and it's good to have a record of the original, factory dimension.
1) Switch/Linecord
>The two motor leads have to be disconnected to free this item from the motor. The switch's wiring terminals are the 'push-in' type. By poking the shank of a 1/16" twist drill in alongside a wire, you can deflect the terminals' springy contact and release the wire with no harm done to the contact.
2) Pinion Gear
>There's a small external snap-ring at the end of the shaft, suggesting that the gear should just slip off the shaft once the snap-ring is removed. From what I've seen of most readily available snap-ring pliers, pliers with small enough tips to fit a snap-ring this size are not so easy to come by. I solved this problem for myself years ago by filing the tips of a pair of snap-ring pliers to fit small rings. You may have to do the same. It's a painstaking bit of work, but quite doable.
>With the snap-ring off, the gear proved to be stuck on the shaft. There wasn't space to get a puller on it, and prying with a screwdriver didn't work. And what there is to pry against is the plastic end-frame of the motor, which limits how forcefully one dares to pry. As I was rummaging through my drawer full of pullers, I came across a vehicle door trim remover that I'd bought long ago and all but forgotten that I had. I tried it on the gear, and it turned out to be the perfect pry bar for the job. It provided sufficient leverage while doing no harm to the plastic end-frame.
>One can expect to run across this sort of snag on old machinery. All it takes to make a slip fit an obstinate fit is a tiny bit of rust or sticky fouling on a shaft or in a bore.
3) Cooling Fan
>Another snag. The cooling fan is a plastic disc with twelve straight, centrifugal blades on it. Its means of attachment to the shaft wasn't obvious. It didn't appear to be threaded, though I tried twisting it in both directions -- to no avail. That left pulling it off, but I could see no way of applying a puller that wouldn't damage the part. With a 1/16" twist drill, I drilled the plastic hub directly alongside the shaft at nine places around the shaft to relieve the hub's grip. That worked. I was able to twist and pull the fan off. 'Turns out the fan's bore was pressed onto a finely splined shaft -- a very secure fit indeed. There's still enough left of the fan's bore that the fan should fit back on properly, and at final reassembly I'll fill all the drill holes with epoxy.
>If I had it to do again, I'd try drilling two 11/64" holes through the fan 180 degrees apart so as not to imbalance it at all. I'd get the holes as near to the shaft as possible, where the disc is thicker. Then I'd have a means of installing a couple of 8-32 screws with nuts and rigging a puller.
4) Brushes
>The brush holders and springs were well thought out in this motor. The springs are torsion springs that are easily backed off and moved aside for brush removal. There was a snag, though, in that one of the brushes had overheated and was stuck in its channel. I did some harm to the face of the brush as I pried at it to free it up. Nothing fatal, but not good. I should have sprayed it with WD-40 first; that might have made it easier to nudge the brush loose.
4) Commutator End Frame
>Two No.8 x 2 3/8", 1/4" A/F hex washerhead screws.
>Since the bearing had no balls in it, the end frame came away easily. With the two long screws out, the motor's field winding frame and its other end frame were no longer attached, and I wanted them to be held together until I could get the armature out. I put the screws back in with two 7/8" long, 1/4"-20 coupling nuts under their heads for spacers, to take up the screw length formerly taken up by the commutator end frame.
5) Outer Bearing Race
>This part was a light interference fit in the plastic end frame. I was able to punch it out a little at a time by engaging a small chisel with the groove in the bearing race from the outer side of the end frame.
6) Armature
>Easily pressed out of the remaining plastic end frame on a hydraulic press. There was a wavy washer on the bearing's outer face, presumably to provide a bit of axial preload to the assembly.
7) Business End Bearing
>There was a substantial e-clip on the shaft serving as the bearing's axial position reference/stop. With the e-clip pried off, it was easy to get a small, two-jawed puller on it and pull the bearing off. Prying off the e-clip had to be done carefully so as not to harm the windings.
8) Inner Race of the Commutator End Bearing
>This was tricky because the part was too small to afford any purchase to a puller's jaws. As with the other bearing, there was an e-clip to remove. With the e-clip out of the way, I had just enough room to cut through the race with a small cut-off wheel in the Dremel hand grinder. I did a bit of harm to the shaft's surface, but not enough to have any ill effect on installation of a new bearing.
9) Business End Frame
>'Removed the two screws that I had put back in with spacers in item 4 above.
>I blew off all the greasy sawdust that I could and degreased it in the parts washer. For a follow-up on parts like this, I spray them down liberally with Fantastic and rinse them with scalding hot water while wearing nitrile gloves. Blind screw holes must be blown thoroughly dry before reassembly. Pipe cleaners are helpful as well for drying out blind screw holes.
10) Armature
>'Needs a thorough blow off with compressed air.
>I chucked it in the lathe and burnished the commutator with 600 grit silicon carbide paper, followed by 1200 grit. A jeweller's screwdriver works nicely for scraping the gaps between the segments. Just prior to reinstalling the commutator end frame, I'll wipe it off with lacquer thinner to make certain that it's free of any oily contaminants.
Bearings
Both bearings are the same; they're NSK No. 6900ZZ -- 10mm bore x 22mm O.D. x 6mm width, shielded both sides. I mentioned to the guy at BDI Canada, the bearing distributor, that a sealed version might be in order as a replacement, and he said that sealed bearings are avoided in hot-running applications; the seals will tend to quickly go to ruin. A serious wood cutting session in July would no doubt make for a very warm motor, so I went with a shielded replacement. The BDI fellow tried to find me a less expensive bearing, but it turned out that NSK is the sole source for this particular bearing, so NSK it had to be; $15.80 plus sales taxes. A new saw is about $70.00. Small wonder that the landfills keep filling up, eh?
The one good original bearing spun very freely, which is indicative of a grease-starved bearing. It's possible to pry off a shield on a bearing with relatively little damage to it by shoving the sharp point of a scriber between the shield and the inner race. I did that and, sure enough, the bearing's interior looked like a grease-free zone. I let it sit in the parts washer's solvent for a week, then thoroughly rinsed it and blew it dry. (By the way, it's considered a poor practice to set bearings to spinning with compressed air; you can cause them to spin without lubricant at outrageous speeds by doing that -- not good.)
For a bearing grease, I'm partial to Canadian Tire's "Motomaster" brand "Wheel Bearing & Chassis Lubricant". (My truck's front wheel bearings have been running in it for a couple of years now since I replaced the rotors and bearings.) I'm probably guilty of overfilling the bearing with grease, but I figure that if excess grease seeps out when the thing warms up, no harm can come of it since this bearing will be at the end opposite to the commutator. I reseated the shield by going around its outer edge with Channellocks, gently squeezing its lip back in place. It might be possible to press or punch it back in place, but you'd need an adapter the full diameter of the bearing, and you'd need to get everything set up for a dead square start -- easier said than done.
Motor Reassembly Notes
A 10mm, six-point, deep 1/4" square drive socket served as a pressing tool for pressing the bearings back on the shaft by their inner races, but a bit of modification was called for. As with most socket wrenches, the hex opening of this one was quite severely chamfered inside to make it easy to slip the wrench over a nut. I chucked it in the lathe and with it spinning, applied a small grinding wheel in the Dremel tool to it to grind its end down to where most of the chamfer was gone. That gave me a pressing tool that presented flatly to the face of the bearing's inner race.
I found it easier to get the bearings started squarely by hand with the pressing tool and a plastic-faced mallet, than to start the bearing directly on the hydraulic press. The hydraulic press is a wonderful tool, but some items can be awkward to set up on it, and this was one of them.
The remainder of the work was easy and straightforward. The bearings' outer races are a hand press fit in the plastic end frames.
I drilled the fan in two places, as I'd mentioned earlier that I should have done in the first place. I'll be able to apply a puller now should I ever have to remove it again. I used my woodworking vise as a press for putting the fan back on. It went on squarely and looks like it will hold fine, in spite of the nasty way I went about getting it off. I'll still shove as much epoxy as I can into all the holes I drilled, though.
Motor Bench Test
I clamped the motor securely in the woodworking vise for a trial run. (Don't even think about doing this sort of thing unless you have an absolutely secure way of holding a motor that in no way involves your hands. Eye protection is mandatory. Universal motors have considerable starting torque; the torque reaction at start-up can be startling. Then they run at a no-load speed in excess of 20,000 rpm. They're not an item to be toyed with. See my anecdote "A Cautionary Tale".)
It runs fine, though the commutator sparking looks a bit excessive to me. It's going to have to do; the likelihood of me finding replacement brushes for this motor is slim to nil. Time to reassemble the machine.
Saw Reassembly Notes
Pinion Gear
The pinion gear can go back on the motor's shaft either end first, but it's best in reassembly to get gears back together in the same mesh they've always had. Though the pinion's teeth exhibited no wear to speak of, it was evident which side of the teeth had been in contact with the large gear's teeth, making it easy to determine how to put the gear back on the shaft.
Snap-Ring
I broke the little snap-ring for the pinion gear while trying to correct a bit of distortion in it with pliers; sometimes it's best to leave well enough alone. I have spares on hand, so that caused me no real grief. (Princess Auto puts up assortments of common mechanic's fasteners in compartmented boxes. They're well worth having in the shop.)
Large-Gear/Chain-Sprocket
I packed the large-gear/chain-sprocket's needle roller bearing with wheel bearing grease, and smeared the sleeve bearing and spindle with it as well. Before slipping the item onto it's spindle, I filled its gear teeth with grease. After installing the gear and giving it a few rotations, I took away all the squeezed out grease. For an arrangement like this one, that's as good as it gets for gear lubrication.
Fasteners
All of the casing screws are of the 'threading' variety; i.e they form their own female threads in the plastic when they're first installed at the factory. The type used here do that by displacing and compressing plastic; no plastic material is cut away as with some types of threading screws. It makes for a very sound and strong female thread. At reassembly, it's important to get the screws started correctly so they run back into the original thread and don't start forming another thread; that tends to lead directly to a stripped thread. A way to ensure engagement with the original thread is to present the screw lightly to its hole, then turn it counterclockwise until you feel it drop into the female thread's starting point. The screw should then run in easily.
An interesting feature of the screws used here is that their threads are a double helix; you can see it if you examine the end of a screw closely -- there are two helix starts. (Hence, 'double-start' screw.) I can't really prove this, but I suspect that such screws are prone to have very slight asymmetry between the two helices. The result of that is that a given screw may run back in more easily from one of its starts than from the other; something to be mindful of if you find that a screw is offering more resistance than feels right.
Wiring Lay
Wiring lay can be an aggravating thing to re-establish in portable power tools; there's often very little space for it, and even stranded conductors have enough springiness to make a nuisance of themselves as you try to get them to stay put while you close things up without pinching any wires. This machine was actually pretty good in that regard; plenty of space, and a well thought out wiring lay.
Whenever you're closing up a wiring cavity, and you start to feel a 'squishiness' as you tighten a screw down on what should be a rigid interface, stop. You're pinching a wire. Open it up again and correct the problem.
Chain Tension
Poulan's instruction manual is a bit less than enlightening on this. After explaining the action of the chain tensioner and taking one through to an initial point of tension, one is told to, "Continue turning the adjusting screw until the tension is correct." [!?] One is not told what the criterion for 'correctness' is. I'll go with 'no slack; no tightness'.
Bar Oil
I looked into this and learned that ordinary lubricating oil is not recommended. Chainsaw bar oil is formulated to be sticky so it doesn't get flung off the chain. I went to Canadian Tire for some and it turns out that the stuff is also formulated for cold weather or warm; what they had on the shelf this time of year was marked "Fall/Winter". At least the price is within reason -- $3.49 for a Yankee quart (946 ml).
And Here It Is
I began this post before I'd acquired a camera, so I don't have a 'before' picture; 'Before' would have looked about the same, only grimy.- - -
SUNDAY, JANUARY 31, 2010
'Oiled the chain with a little oiler I made from a ladies' hair colouring goo bottle, filled the oil reservoir and tried it on a 2x4. It runs and cuts.
The bar oiler appears to have ambitions to be an automatic oiler, judging by the puddle it's leaving me when I set the saw down. I'll have to look into that. Wouldn't hurt to sharpen the chain, too, although it's not in too bad shape.
MONDAY, FEBRUARY 15, 2010
The Bar Oiler
The oil reservoir is a flexible plastic 'bottle'. To dispense oil, you press down on its filler cap, which squeezes the thing and forces oil out of its dispensing orifice. It does seep oil out of that orifice when it's sitting idle. There's no check valve of any kind associated with it, so it's not clear to me how it could ever not seep oil. Perhaps when new, the orifice only opens when there's some pressure applied behind it, but age and use have made it leaky.
Poulan's website is quite impressive for providing service parts, but I won't pursue getting a new oil reservoir -- a bit too much of business and commerce for my liking. If I hang the saw by the hole in the nose of its bar when it's not in use, the oil will be down away from the orifice and won't be able to leak out. Whenever the saw is actually in use, the leakage really won't be a bother; problem solved.
The Chain
On closer inspection, I can see that this chain has been resharpened many times, and not uniformly -- some teeth are shorter from front to back than others. If I had more confidence in my motor overhaul, I'd get a new one. As things are, I'll give this one a touch-up sharpening and live with it. I'm actually unlikely to have much use for the saw.
The chain is made by Oregon, which outfit appears to pretty much dominate the industry. As with all things, when you start looking into the subject of saw chain you discover that there's much to learn, not that I really need to know all that much of it to deal with this chain.
This chain appears to be a fairly light duty, very low kickback design. Typically, every other link of a saw chain has a cutter tooth. On this one, every third link has a cutter tooth, the two intervening links are toothless 'bumper' links. This is probably not a chain that a working professional would have any use for -- it's no doubt been specifically designed to be as safe as possible for occasional use by homeowners.
Saw chains are sharpened mounted on the bar. Presumably, the filings fall away and don't pose a great wear hazard to the chain. Here's a photo of a good setup for sharpening:
There's quite an array of sharpening gear available out there, but at bottom all that's really needed is a round file of the correct diameter for the cutting teeth (5/32" in this case). Adherence to the original chisel angle of the teeth, and consistency of tooth length are what one wants to strive for. That's probably easier said than done; the odd tooth may need more filing than others, and so end up getting shortened more. (By 'shortened' I'm referring to front-to-back length of the tooth, not height. Teeth are never filed on their top surface that I'm aware of.)It's helpful to dab one link with Wite-Out to indicate a start/end point on the chain. I'm inclined to file from a tooth's chisel edge inward, so as not to turn a 'wire edge' on the tooth.
Anyway, this chain is too far gone to be worth fussing over. I've given it a touch-up filing. I'll see what use I find for the machine.
Tuesday, December 15, 2009
Centre Punch Sharpening
If you have a bench grinder, and a reversible, variable-speed 1/2" portable electric drill, you have a 'lathe' to sharpen centre punches with.
Chuck a centre punch's handle in the drill, and arrange it so you can spin the punch's point-cone against a rotating grinding wheel. You want the punch's rotation to be counter to that of the grinding wheel. The punch needn't be spun at very high speed; just fast enough that the grinding wheel's effect on the punch's point-cone is kept more-or-less uniform.
The pointy ends of centre punches are not always perfectly straight, or coaxial with their handles. This method won't work with a crooked or badly off-centre punch, but a true or near-true punch will sharpen up quickly and easily this way.
Chuck a centre punch's handle in the drill, and arrange it so you can spin the punch's point-cone against a rotating grinding wheel. You want the punch's rotation to be counter to that of the grinding wheel. The punch needn't be spun at very high speed; just fast enough that the grinding wheel's effect on the punch's point-cone is kept more-or-less uniform.
The pointy ends of centre punches are not always perfectly straight, or coaxial with their handles. This method won't work with a crooked or badly off-centre punch, but a true or near-true punch will sharpen up quickly and easily this way.
Sunday, December 13, 2009
Welcome
Welcome to Rouge River Workshop. Don't expect much. This project may or may not ever amount to anything. I'd like it to be a place where I can share really sound, useful information about tools, materials, fasteners and methodology.
I mean for this blog to be a bullshit-free zone. You will never find an item here titled something like, "Build This Half-Acre, Three-Level Deck in One Weekend With Only a Nail File and a Hammer". And if you ever catch me posting any bits of 'plausible but unsubstantiated orthodox bullshit', by all means tear a strip off me for it. (And I'll mostly keep it clean, but occasionally, 'bullshit' is the word that's called for so I use it.)
This place is going to be long on words and short on illustrations until I can acquire the gear I need, like a camera and a flat-bed scanner.
By the way, I'm on no one's payroll here. If I mention or seem to endorse a particular vendor or product, I do it for the sake of being informative, not to sell stuff. I have no use for magazine articles that don't tell me how to get something that's new to me, or who makes it, out of some bogus prissiness about not sullying editorial content with commerce. And I won't hesitate to draw attention to shoddy goods or questionable business practices.
Anyway, drop by now and then. Someday, I might even explain the curious line below the blog's title.
SATURDAY, SEPTEMBER 18, 2010
Addendum
As a boy, I was much taken with American publications like Popular Mechanics and Mechanix Illustrated. To see the things that could be done with tools and materials conveyed on the printed page delighted and fascinated me, and I long harboured an ambition to create such material. In the corporate lay-off spasms of the early nineties, I had an opportunity to pursue that ambition and had some modest, fleeting success at it. But the imperatives of a steady pay cheque and keeping an old truck running took me away from it.
But now we have the internet and Blogger, and they've provided me a means of creating what I've long dreamt of -- my own workshop magazine. The only downside is that the money is pathetic, but there's a huge upside for me -- no editor(s), or at least, I'm the editor, every last one of them. What I publish here can stand or fall on its own merits, without the dubious benefit of having been vetted or improved upon by my intellectual betters.
So there you have it, Rouge River Workshop is an aging boomer's boyhood dream realized, such as it is. Please don't hesitate to let me know what you think of it.
I mean for this blog to be a bullshit-free zone. You will never find an item here titled something like, "Build This Half-Acre, Three-Level Deck in One Weekend With Only a Nail File and a Hammer". And if you ever catch me posting any bits of 'plausible but unsubstantiated orthodox bullshit', by all means tear a strip off me for it. (And I'll mostly keep it clean, but occasionally, 'bullshit' is the word that's called for so I use it.)
This place is going to be long on words and short on illustrations until I can acquire the gear I need, like a camera and a flat-bed scanner.
By the way, I'm on no one's payroll here. If I mention or seem to endorse a particular vendor or product, I do it for the sake of being informative, not to sell stuff. I have no use for magazine articles that don't tell me how to get something that's new to me, or who makes it, out of some bogus prissiness about not sullying editorial content with commerce. And I won't hesitate to draw attention to shoddy goods or questionable business practices.
Anyway, drop by now and then. Someday, I might even explain the curious line below the blog's title.
SATURDAY, SEPTEMBER 18, 2010
Addendum
As a boy, I was much taken with American publications like Popular Mechanics and Mechanix Illustrated. To see the things that could be done with tools and materials conveyed on the printed page delighted and fascinated me, and I long harboured an ambition to create such material. In the corporate lay-off spasms of the early nineties, I had an opportunity to pursue that ambition and had some modest, fleeting success at it. But the imperatives of a steady pay cheque and keeping an old truck running took me away from it.
But now we have the internet and Blogger, and they've provided me a means of creating what I've long dreamt of -- my own workshop magazine. The only downside is that the money is pathetic, but there's a huge upside for me -- no editor(s), or at least, I'm the editor, every last one of them. What I publish here can stand or fall on its own merits, without the dubious benefit of having been vetted or improved upon by my intellectual betters.
So there you have it, Rouge River Workshop is an aging boomer's boyhood dream realized, such as it is. Please don't hesitate to let me know what you think of it.
Subscribe to:
Posts (Atom)