Friday, August 26, 2016

A Grubby Old Electric Space Heater With A Noisy Fan Motor

This old heater has outlasted its warranty period by decades.

I haven't cleaned it in a long time, so it needs to be at least partially dismantled for a good cleaning. It's also exhibiting a clattery fan motor bearing, so I need to look into that and see if I can come up with a solution.

A single, vertical tie-rod and two thermostat connections are all that need to be undone for lid and cover removal.

Three screws and two spade terminals are what's holding the heating element in place.

The fan has its own mounting brackets held in place by four screws, plus its two spade terminal connections that piggy-back onto the heating element's connections.

And here's the fan out of the heater's base, with its mounting brackets still in place.

Note the dust accumulation on the leading edges of the fan blades. The dust accumulation throughout the heater is awesome. Any fan-cooled household appliance is susceptible to such accumulation, and ought to be periodically inspected for it and cleaned of it. I've let this heater go for too long without tending to it.

The fan motor exhibits just the condition I expected it to; i.e. perceptible, excessive clearance in its fan-end sleeve bearing. That accounts for the noise that it makes.

Next up is to pull off the fan. Then I'll be able to dismantle the motor, and see if there's anything I can do about the bad bearing. Here's a view of the fan being pulled off by a little puller I devised for this.

With the fan off, I dismantled the motor and got a good, close look at its fan-end bearing. It turns out that the bearing/shaft interface is just fine -- that was not the source of the excessive clearance and noise I'd observed. Instead, the spherical, self-aligning sleeve bearing is loose in its keeper inside the mount. Here's a view of the bearing in its keeper in its mount.

I could see no way to snug up the spherical bearing in its keeper, but the fact that both bearing mounts in the motor are identical gave me an idea. I transposed the two bearing mounts, so the good one was at the fan end of the motor. I reinstalled the fan and gave the assembly a trial run. That appears to have done the trick.

I'll clean and reassemble the heater, and see if my repair method has truly cured the fan motor of its noisy operation.

- - -


Transposing the two bearing mounts worked. The motor now runs quietly.

The reason it worked lies in the distribution of radial forces between the motor's two bearings. Any slight imbalance of the fan's blades results in a radial force that must be borne by the motor's bearings. By far, most of that force is borne by the bearing nearest the fan. Since that was the loosely retained bearing, it would tend to clatter within its keeper.

Moving that loose bearing to the other end of the motor relieved it of absorbing the radial forces exerted by the fan -- clatter gone.

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A Line Cord Repair

The line cord's jacket has separated from its strain relief on my ancient Stanley belt sander, and strands of jacket filler are billowing out.

It looks awful, and it's not something I should neglect, so here goes with a repair.

The sander's handle is the connection box. Remove four obvious screws to open up the handle.

Note that the front-most screw is shorter than the others. Here's what's inside the handle.

The line cord presently installed is a replacement for the original, so the two wire nuts were originally top hat connectors.

And here we are with the line cord's jacket back in it's strain relief as it ought to be, and new connections made for inside the handle.

Now I can button that up and have the use of the sander back, at least until the next time the line cord needs attention.

- - -

Line cord failures are most likely to occur right near where the cord enters the appliance -- that tends to be where the line cord experiences the greatest amount of flexing. Right where the line cord joins its plug is another stressful spot that's liable to fail with prolonged use. Repair is easily effected, as it was in the example above.

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Tuesday, August 23, 2016

A Four Hook Key Hanger With A Flaw

This is a not unattractive little piece of brass work.

But there's a problem with it; i.e. while the hanger provides four hooks for hanging keys on, there's no provision for a way to hang the hanger itself. I'll have to drill two holes for No. 4 brass screws, so I can attach the thing to a wall or something, and have the use of it. Here goes.

- - -


I had some empty space on a cleat under a tool cabinet, so there it went. Countersunk, flat head screws would have been nice, but I don't have any No. 4 brass ones, and No.6 would have been too large.

- - -

I found that key hanger in my next door neighbour's garbage, by the way. Now, before you go thinking, "Oh my God! The guy rummages through people's garbage for stuff -- his next door neighbour's yet. Has he no shame?", permit me to explain.

My neighbour had to be away for garbage-setting-out day, so he asked me to take care of his bin for him. I peeked inside the bin when I went to set it out, hoping there'd be room enough left for an item I wanted rid of, but didn't have space for in my bin. That's when I spotted the key hanger and snagged it. It's not like I was rummaging, ok?

Anyway, rummaging or not, people do throw away some pretty good stuff at times, and it's a shame to let it go to the landfill, surely.

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Friday, August 12, 2016

'Bumping' A Small Paper Shredder's Cutter Bars

[I have an Omnitech model OT-EXC6A that's well out of warranty. It still works well, but I've noticed lately that it's inclined to run roughly and labour at times. I looked at the underside of the shredder head, and could see evidence of stuck bits of paper in the cutter bars' teeth that weren't clearing out. (I suspect that shredding paper with adhesive tape on it contributes to this.) Picking out those bits would probably clear up the trouble, but how to get at the full circumference of the two cutter bars? By 'bumping', of course.]

- - -

In automotive mechanics, 'bumpimg' an engine is to operate the starter for a brief instant, in order to rotate the engine to a more favourable internal position for some work to be done on it. With paper shredders, a similar method allows you to thoroughly inspect the cutter bars, and pick them clean of stuck matter that's making the shredder run roughly.

In a nutshell, here's how it's done:
  • Fwd/Auto/Off/Rev switch set to Fwd.
  • Shredder head upside down on a work surface.
  • Shredder plugged in.
  • At the centre-rear of the shredder head, there's a bin interlock microswitch button visible. Poke that button with a small screwdriver, and you can 'bump' the shredder's mechanism around little-by-little to inspect and get at all of the cutter bars' teeth. Pick out the bits of stuck material with a mechanic's pick and pointy tweezers.
The shredder will run better afterwards.

- - -

Or not. The apparent improvement in performance that I observed from picking out stuck bits of paper from the shredder's teeth was short lived. I've since been told that oiling the shredder's cutter bars is hugely beneficial. We'll see.

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A Brook Electric 1 HP Motor

This old motor was on a Rockwell/Delta 10" table saw of my acquaintance. The post concerning the saw is here.

Here's a view of the opposite side, where the connection box is.

And here it is with the connection box opened up.

That's the most spacious connection box I've ever seen on a motor.

Following is a transcription of the I.D. Plate data:

  • FRAME EL143T
  • SERIAL No. 185079T
  • H.P. 1.0
  • F.L.SPEED 1700
  • V. 115/230
  • A. 14.2/7.1
  • Hz 60
  • PH 1
  • CODE K
  • MAX. AMB.°C 40
A couple of points about the above:
  • "TEFC" stands for 'Totally Enclosed Fan Cooled'.
  • Note the current rating (A.) -- 14.2 Amps at 115 V! This is a motor that ought to be run from 230 V. (It's currently wired for 115 V.) It's liable to be a circuit breaker tripper if plugged into a household 15 A circuit.
The saw this motor came from must have been on a job site once where it was raining glue. The thing is an awful mess -- just encrusted with some sort of hardened muck. To restore it to good appearance, I'd have to tear it down and go at the pieces with paint remover, probably. I may do that, but not right away. I need to check this motor out and wire it for 230 V. If all is well, I can use it again back on the saw it came from. That saw is meant to get a restoration.

So, permit me to go test this motor at both voltages. 'Be back shortly.

- - -

That all worked out fine; the motor runs at either voltage.

The Wire Ends

The motor's connection wiring is of stranded wire; the stripped ends were never tinned. I don't care for that -- I like stranded wire ends to be tinned so they don't fray and lose strands. I may as well take care of that right now. Here's a before view of the wire ends.

Yuck. I can do better than that.

- - -

And here we are with the wire ends tinned.

That's better but not great. Some of those wire ends were in dreadful condition, and didn't take tinning as well as I would have liked. I may end up splicing on short lengths of wire, and insulating the splices with shrink tubing. That will give me fresh wire ends that can be properly tinned for connecting with wire nuts. We'll see.

The Output Shaft And Pulley

They're not pretty.

The shaft is 7/8" diameter. Should I ever want to increase the saw's blade speed by installing a bigger pulley, I won't be able to just go to Canadian Tire for one. The biggest standard pulley bore that's widely available at outlets like Canadian Tire is 3/4".

The pulley is steel, 3 3/4" diameter.

Both the pulley and the shaft look awful. I should get the pulley and the key off, and clean up the works. I'd like for the pulley's axial position on the shaft to be readily adjustable when it comes time to mount the motor on the saw for a trial of the saw.

- - -

And there we are with things cleaned up somewhat -- at least the key and the pulley now move freely on the shaft as they ought to,

The pulley wasn't seized on the shaft, but I needed a two-jaw puller to coax it off. The key was a bit odd. It was jammed in its keyway and had to be forced out. It's nominally a 3/16" square key, but it was oversize. I had to lap it considerably on a sheet of aluminum oxide abrasive paper to get it to fit properly. It must have been forced into place at the factory or wherever, and the pulley forced on the shaft over it.

The Box Connector

This is a frightful little mess of a thing.

It appears to be a 3/4" fitting -- 1/2" would be quite adequate. I can't imagine what whoever installed that had in mind. I'll be replacing that with something more suitable.

- - -

Anyway, that's the story so far. This old motor appears to be in fine condition, aside from its cosmetic issues. It's now at least fit for service, once I'm ready to give the saw it belongs to a trial.

* * *

Back again. I was having so much fun with this I thought I'd return to it.

More On The Box Connector

That cable connection point at the centre top of the connection box is not 3/4" pipe as I thought. The diameter is about the same, but the thread pitch is finer -- it's 16 tpi, yet it's a tapered thread like a pipe thread. It's something I've never encountered before.

What I'll do is I'll cap off that hole up top, and make a new hole in the side of the box to accept a 1/2" box connector. Here's what I've come up with to cap off the useless hole

Basically, two 1/4" fender washers and a 1/4"-20 screw. The assembled appearance is pretty good.

The Cooling Fan

The cooling fan resides under a vaguely bell-shaped cover at one end of the motor.

And here's the cooling fan revealed.

That fan appears to be a press fit onto the end of the motor's shaft. The likelihood of my getting that fan off without damaging it is slim to nil. That pretty much obviates an attempt at a full blown restoration job on the motor.

Sandblasting The Motor's Frame

To improve the motor's appearance, not to mention its air cooling, I had the idea to take my toy sandblaster to the motor's frame, if only to see what sort of result I would get. (Since the motor is a sealed unit with the connection box's cover in place, I could sandblast without fear of harm to the motor's innards.)

The result turned out to be not too bad, though far from perfect. Here's a view of the motor after sandblasting.

It looks good enough now that I may strip and paint the connection box and the fan cover.

A New Connector For The Connection Box

In the end wall of the connection box, opposite the capacitor, I drilled a 5/8" diameter hole and filed it out to 13/16" diameter. Now I have a place for a 1/2", 90° connector, like so.

That's much better than the nonsense that was originally installed in the top of the box.

- - -

To be continued.

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A Rockwell/Delta 10" Table Saw -- Part II

[Part I of this post is here. I left off part I having just completed the overhaul of the arbor assembly (new bearings; axial run-out eliminated from saw flange face). I've since brought the machine inside the workshop from where it was under the carport, and can now reassemble the machine for a trial.]

- - -

Chassis Mounting Holes At Rear

The abuse that machines take -- the two rear holes in the chassis' lower lip for fastening the chassis to the stand are pulled out.

I'll see how well I can hammer that back to something resembling what it ought to be.

- - -

I got a reasonably good result.

Fortunately, that's not a critical part of the saw's construction.

The Motor Mount Platform

The platform pivots on a 1/2" diameter steel rod. There's provision for a 1/4"-20 setscrew to lock the rod in place, but there's no setscrew. I'll correct that if and when I do the restoration.

The Motor Mount Seen In Its Normal Orientation

Note that there's no provision for a belt tension adjustment; belt tension is, in effect, set by gravity. The motor's weight tensions the belt as the motor mount pivots to where the belt restrains the motor from pivoting any further.

That's not a belt tensioning method that I approve of. I think it tends to result in greater tension than is required. I'll see if I can come up with a belt tensioning adjustment scheme.

Elevation Screw Trouble

I got the arbor assembly back into the machine, and meant to install the elevation screw. That did not go well.

The elevation screw and nut do not align with one another correctly. Here's a view of them that I hope shows the trouble adequately.

The screw's axis is significantly off to the left of the nut's axis. I got the screw and nut to mate partially like that, and the screw was very difficult to turn. That no doubt explains why one of the saw's plastic handwheels is broken where it keys to its shaft. This saw must have had this defect right from the factory.

I'll take the arbor assembly out again, and see if I can get that nut to align better.

- - -

Time Out

The difficulty and complexity of this project are going through the roof. I may or may not have the wherewithal to see it through to a successful conclusion.

I'll carry on, but I'll suspend the blogging part for now -- it's just too much to write about to no particularly good end. I'll return to this post when I have something worthwhile to contribute to it.

* * *

Back At It -- SATURDAY, SEPTEMBER 3, 2016

I've done a fair bit of work on the saw and its stand, and I'm now ready to start reassembling the fully dismantled saw. It will be slow going, because I've yet to paint the two major motor mount components, and they need to be painted prior to final reassembly.

Anyway, here's where I'm currently at.

Table, Frame, Trunnions And Arbor Assembly Back Together

Here's an underside view of all that.

Four 5/16" screws fasten the frame to the underside of the table, and four 5/16" screws fasten the trunnions to the underside of the table. The trunnions' screw holes are considerably oversize, to provide for parallelism adjustment. I've positioned the trunnions at design centre, and tightened the screws. I'm hoping that I'll have sufficient adjustment latitude at the rear (easily accessible) trunnion to achieve parallelism, without having to disturb the front trunnion. The saw will be upright on its stand for the parallelism adjustment, and if I have to adjust the front trunnion as well as the rear, I'll be in for a difficult time; the front trunnion won't be at all easy to adjust on an upright, fully reassembled saw. We'll see how that turns out.

The Tilt Indicator Rod

Something tells me that this feature of the saw is lame and gimmicky. I'll give it new red paint at its indicating tip, and I'll want to have it in place before I turn the saw upright, but I doubt that it will ever be of any use. Adjusting it will not be easy.

- - -

The Tilt Screw -- SUNDAY, SEPTEMBER 4, 2016

Here's the tilt screw back in place.

To be continued, maybe.

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Wednesday, August 10, 2016

An Electronic, Battery Powered 'Candle'

An electronic candle in the household wasn't my idea; it was the idea of someone near and dear to me. She'd had it in mind as a grave candle in memory of her father-in-law, and she did put it to that use for awhile.

But the candle proved unreliable, and it ended up on the 'things to attend to one day' shelf of our home's storage room. I came across the candle the other day, and asked my wife if I could throw it out. She replied that I could throw out the electronic innards, but she wanted the shell to be a holder for a real candle. Hmmm. I thought that was a reasonable compromise, so I embarked on making a minor workshop project out of the candle.

Here's a view of the candle operating in near darkness.

And here is is with the lights on.

I'm inclined to think that electronic candles are pretty kitschy, but maybe that's just me.

Anyway, following is my account of the dismantling of the candle so I could toss its innards, and the shell's conversion to a proper candle holder.

Dismantling The Candle

At the underside, the battery cover comes off and the three C cells come out, of course. A thin, transparent, amber-coloured top cover comes away. That leaves me with the candle's inner assembly inside it's decorative black shell. Three small screws at the bottom come out, the bail is removed and the inner assembly is free to come out the top. Here's what you end up with.

The 'flame' is in a fairly deep recess at the top of the inner assembly at the right. That assembly is a glued together unit -- there's no nondestructive way to open it. Doesn't that just beg for further action? I think it does. Here goes.

- - -

After some prying and snapping of plastic, I got to here.

There's a tiny circuit board up inside that the 'flame' LED is no doubt mounted on. The circuit board is well adhered, and doesn't want to come away easily. A 90° pick tip might convince it. Here goes.

- - -

And there we are -- a white LED, and a circuit board with what must be a tiny IC encapsulated on it.

The IC must provide a couple of functions:
  • The three-position slide switch on the underside of the unit is labelled 'ON/OFF/Timer'. Whatever the 'Timer' function does, I imagine the IC is in control of it.
  • The LED does a fake flicker, in imitation of an actual candle flame. Again, the IC must control that effect.
So there we are; the innards of a fake candle.

Making A Floor For The Candle's Shell

Since my wife wants the shell for holding a real candle, I'll have to come up with a suitable disc to install as a 'floor' in the shell. Fortunately, there's an inner lip at the bottom of the shell that will make it easy to install a floor. Here's a view of that.

That lip is most helpful. I can just drop in a disc of the correct diameter, and there are even tabs with screw holes in them for fastening the disc in place.

A Sheet Metal Disc Floor

I pondered how to go about this for awhile, and finally decided on a floor made of appproximately 0.020" thick galvanized steel. Here's what I've ended up with.

At final assembly, I'll replace those ordinary hex nuts with Nyloc nuts, so the assembly can't loosen up on its own. Meanwhile, here's how a trial assembly looks.

With that disc painted flat black, the whole thing should look like it was always a holder for a real candle.

All Done

Here's the item fully reassembled, with its floor painted flat black. I just grabbed any old candle I could find to put in it -- my wife may have a more attractive candle in mind for it.

And here's the candle burning in near darkness.

Imagine that -- a candle that never needs batteries, or is troubled by oxidized battery contacts.

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Tuesday, August 9, 2016

A Roll-Around Tool Tray

My next door neighbour is moving out, and he gave me this item for free.

It's made by POWERBUILT. As far as I can discover, POWERBUILT is a Taiwanese tool-making outfit. If this tool tray is any indication, they make pretty good stuff.

The tray is ruggedly built and good looking. (I think the colour may be off because of much time out in sunlight.) The only thing about it that puts me off a bit is the extreme outrigging of one 'foot'. Just how tip-proof does a roll-around toll tray really have to be?

The outrigger is fastened in its position by a single M10 x 20mm long screw w/washers. like so.

There's only that one position for fastening the outrigger in place -- there are no adjustment options. I'd be happy to have the outrigger collapsed, like so.

The tray would still be plenty stable enough for safe work with it.

To obtain a fastening position for that, I'd have to drill and tap another M10 hole in the outrigger's slide-pipe. That's doable -- I just need to have the unit on a nice, flat floor surface first so I can mark the hole location correctly. That's something to do for later.

- - -

A Priority Alteration

That outrigger was really bugging me, so I've brought the tray from outside into my workshop to deal with it. Even though it's not high on my list of priorities, I'd really like to have this tray in good order, and ready for use.

[One of the perks of retirement is that you can jerk things around to suit yourself, instead of being jerked around by things.]

- - -
Now I Get It!

Getting the tray inside the workshop somehow made me see what most of the real problem with the outrigged foot is -- the tray was installed 90° around from its correct placement. If you look at the first photograph in this post, you'll see it.

The tray is asymmetrical lengthwise. The tray's longer end is supposed to extend out over the outrigged foot -- not off to one side as it does in the photo. With the tray's orientation corrected, the outrigging is less objectionable, though it still strikes me as extreme. I'm still going to go ahead and collapse the outrigger, and I may provide it with an intermediate position as well.

Outrigger Extension Adjustability

I've drilled and tapped two more M10 x 1.5mm pitch screw holes to give the outrigger two additional positions. (Note that you can see the original colour in this photo at the end of the slide-pipe.)

That was actually easier to do than I thought it would be. It's mild steel, and the slide-pipe's walls aren't very thick.

Now the outrigger will have three possible positions:
  • Extreme (Factory position)
  • Collapsed
  • Midway
The extremely extended factory outrigger position was probably due to the factory playing it safe with respect to safety. With the outrigger collapsed, the tray is definitely easier to tip if you're trying. A forceful load at either corner at the outrigger end of the tray will start to tip it, but in normal use, such a condition is unlikely to arise.

Missing Corner Bumper Fasteners

The tray's corner bumpers are missing two black nylon, snap-in fasteners; one each at two corners. Here's a view of one such corner.

The holes in the steel tray that accept the original fasteners are about 5.6mm diameter -- not something I'm likely to find a standard, small headed fastener for.

I went with a couple of M4 x 6mm pan head screws that look pretty good, and installed the screws with hex nuts and blue threadlocker. The screws are just barely long enough, so all that really intrudes on the interior of the tray is the two nuts. Here's how it looks in the same view as above.

Tilted Tray

When the tool tray's casters were on a level surface, the tray had a perceptible tilt to it. I installed two 5/16" SAE flat washers as shims where the tray attaches to the top of the post, and that improved the condition quite a bit. It's still not perfect, but it will do. I could make a career out of mucking about with it until I got it perfected, and I really don't feel like doing that.

So, there we are. I've got myself quite a nice roll-around tool tray with the bugs worked out of it, and for a very attractive price indeed.

A Parting Word About The Use Of Roll-Around Tool Trays

Tool trays like the one outlined above are not just an auto mechanic's assistant -- I find them invaluable for use on any project, anywhere. They help you keep your tools and components corraled and readily at hand. They keep you from mislaying things, and wasting time searching for where you put whatever. They're a great help in developing good work habits that save time, and spare you aggravation.

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