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.


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.

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