Refurbishing Atwater Kent Pot Metal Pulleys
 

I started working on an Atwater Kent 30, and the first thing I noticed was that one drive belt was broken and all three pulleys were cracked and distorted. I did some research and found that these early pot metal pulleys usually needed to be replaced and saw some methods of producing new pulleys. However, the easiest route would be to pull some brass pulleys from a later AK model.

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https://lh4.googleusercontent.com/-v...20%2520400.jpg

Easiest? I'll never fall into that trap! That's for normal people. Instead, I decided to refurbish the original pulleys by reinforcing them with epoxy resin.

Also, the bronze belts were in rough shape. A previous owner had even tried to solder the belts to the pulleys.

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I let 3-in-One oil soak in for a few hours and removed each pulley in one piece--unlike the ones in the top photo.

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To get good adhesion of the epoxy, I thoroughly prepared the metal: First, a degreaser cleaning in the ultrasonic to penetrate the cracks; then a water rinse followed by distilled water in the ultrasonic; then an alcohol bath to get the water out of the nooks and crannies; and finally overnight drying.

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I brushed on the epoxy, trying to flow it into the cracks. When that was done, the pulleys were almost entirely coated with epoxy.

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After 24 hours I sanded the epoxy back get roughly flat surfaces with particular attention to smoothing and properly shaping the perimeter surface that contacts the belt.

https://lh5.googleusercontent.com/-P...30%2520409.JPG

I cleaned the unbroken belt and burnished out most of the wrinkles. The pulleys got a quick coat of paint, and after it was reassembled the mechanism worked smoothly.

https://lh3.googleusercontent.com/-F...30%2520411.JPG

Well, this was all just for fun. I ordered new belts (adamsradio.com) and I picked up the cheapest possible AK 42 on ebay to get brass pulleys for the AK 30 and some power unit parts for my unfinished AK 42. Plus, now I'll have an extra set of pulleys, which is really good because you never know when you might get shipwrecked on a desert island...

I think the near future days of an affordable Joe Homeowner/hobbyist being able to make/reproduce any type of mechanical parts via a 3-D printer will be almost as revolutionary as the Internet. The 3-D printing industry is already using high-tech metal toner mixes. Scan in the part and hit print from your computer and there's your part in a few minutes. Amazing to me, and why this technology is being called the 3rd Industrial Revolution..

https://www.youtube.com/watch?v=JM0WfQGkAUE

https://www.youtube.com/watch?v=McDz...J5-1blE1h4YdTw


https://www.youtube.com/watch?v=KxiDwbFzWY4

Tom (PK)

Before hobbyists can obtain sophisticated 3D printers, a much wider selection of commercially produced "niche" items (such as knobs) should be available at much cheaper prices. But it's still more rewarding to find an original part or more fun to make one yourself.

Nice job on the pulleys.:D
I once made a dial to cap coupler for a Stromberg 641 Treasure Chest out of an old brass combination lock bolt. Took most of a Sunday afternoon, but worked great, and I didn't draw serious blood in the effort. Have more bolts and more Strombergs, and Winter is fast approaching. :yes:
Kevin

I would have used the intact one as a pattern for a sand mold, then cast new ones out of aluminum or brass.
BTW if anybody needs any small parts cast out of any metal I can do it.

I don't expect to start metal-casting myself, but I am curious. Let me throw a few questions:
What type of metal?
What melting point?
How do you heat it?
What do you heat it in (crucible)?
How detailed is the casting?
Do threaded holes have to be machined?
Did you see the show about the retired alloy casting guy who made fake tokens that would fool high-dollar gaming machines?
Thanks. I'll keep in mind your casting capabilities.

Sure winky,
metals include copper, brass, led, aluminum, and cast iron.
Never measured melting points.
oxy acetylene rosebud torch
metal ladle lined with sand and core wash to hold the sand in place
The sand is super fine, amazing detail
yes you must clean up and tap holes
No i did not see the show, but have made pieces for cast iron toys and old slot machines in the past that fooled experts.
In fact now that I moved and got settled in I'm going to cast some of those brass lamp shades that are always missing on the rca radiola's.

Thanks. These processes have always fascinated me ever since I was a kid trying to make pennies with aluminum foil molds, plaster, and paint. Even at 10 years old I eventually realized that it was cheaper to buy them.

This is a dying trade. The man who taught me passed away a few years back.

Hey Stu:
Have you thought about how the lamp hoods will attach, were you going to cast the metal retaining tabs into them? Put me down for one of those, I could use one.
Thanks

Gregb

Yea the one I got has those 2 tap things on it, and it's the only one I have. I'll make a pattern from it, and cast the rest from that pattern.
I'll have to make up a new mold box first.

I'd suggest entombing something with the tab sticking out into the mould. "Cast" anything is usually quite brittle (Copper excluded.) and they may not even bend over once for installation without snapping.

I cast them out of a softer brass so they wont snap off.

Stu, you PM'ed me yesterday and I tried to answer but VK says you have it set not to receive messages. Could you fix that and PM me again?

I checked ny settings and everything is correct, I have been getting pm's from others.

One of the best things to cast these short of parts out of is defunct automotive carburetor bodies it is a zinc alloy and this what so many of these old pulleys where made of. The alloy used in carburetor bodies has a 350 degree lower melting point then aluminum, they cast to a fine finish requiring very little if any finish work. The problem, of course, it the cost of setting things up.

The only thing you have to watch using aluminum and similar alloys is shrinkage. Although IIRC cast iron has the most shrinkage.

That is the beauty of the zinc alloy used in the carburetor bodies it has very little shrinkage, which is one of the reasons it was used the castings needed very little beyond cleaning up material from the casting, fill and vent holes, to
to do the final finishing work.

Next time I get to the scrap yard I'll have to pick a few up and try it. Might be good for making patterns.