source for replacement friction disc?

I have an ancient chain hoist which wasn't holding the hook. As fast as I cranked it up, the hook would slip back down once I let go of the chain. I tore it down and found that the friction clutch disc had worn to the point where it hardly bore.

This is an awesome old chain hoist which Ernie gave me. I really want to make it work correctly again. Has anyone else solved the problem of where to get a custom one-off replacement friction disc?

For an explanation of how the friction clutch works in a chain hoist, see:

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I see lots of manufacturers of friction material listed on thomasnet.com, but finding one which will make an affordable one-off part for me is totally another thing. If I had to, I could buy the smallest sheet possible and make the disc on a lathe, using a method about like this:

mount an X-acto knife in a boring tool on center height, parallel to lathe axis put a lathe center in the lathe spindle move the cross-slide until the knife point is on the lathe axis i.e. pointing exactly at the lathe center zero the cross-slide dial & remove lathe center put the faceplate on the lathe spindle cut a disk of plywood the size of the faceplate cut a disk of the friction material the size of the plywood (or smaller) punch identical bolt circles in the material and the plywood bolt through to the faceplate, so its faceplate|plywood|friction material crank the X-acto knife out the radius of the inner hole start the lathe and feed the knife in, cutting out the ID crank the X-acto knife out to the radius of the disc OD cut out the disc

But I don't want to buy a whole sheet!

Anybody been through this?

Grant

Reply to
Grant Erwin
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How could they wear it to this point, if it became unusable before it got to this point?

The various friction disks that I had seemed not too easy to make. (esp. when the risks are considered)

i
Reply to
Ignoramus2733

I've never thought of a chain hoist as a precision machine. Does the friction material have to be perfectly round that you have to do all the steps you have described? Why not just use the technique for making common gaskets?

Reply to
E Kinney

..............What are the dimensions?

Reply to
fgrey
?

Well, I put it back together, but I'd guess the original thickness was about 1/4" (wouldn't matter if I replaced it with something slightly thicker) and the OD is probably about 5".

Grant

Reply to
Grant Erwin

There was probably a long period where it pretty much worked but would slip under a heavy load so they'd use it on a light load. It's a pretty old hoist, made by Timken in Philadelphia. Anyway, it's certainly worn. I'll tear it down again and shoot a photo of the worn disc. There's a thin edge where it isn't worn, that part is about 1/4", the rest is worn down to about 3/16".

Grant

Reply to
Grant Erwin

That's simply the only way I know of to cut clean disks in tough rubber sheets. How would you do it? The OD would be pretty easy, could cut that with tin snips. But the ID - oy vey. Well, maybe a hole saw would work.

No, it isn't precision, but the closer you cut it to perfect, the more material you have that bears so the better it will work. You could hack out the middle with a chisel and make a square hole, but the friction disc would have less bearing area ..

GWE

Reply to
Grant Erwin

I have but it was in Singapore so it won't be of much help in the U.S. but contact any industrial clutch/brake supplier -

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example

Bruce in Bangkok (brucepaigeATgmailDOTcom)

Reply to
brucedpaige

Grant, I don't have an easy solution for you. I was curious how big a whole sheet is, and how a big sheet would be shipped without breaking it (the package value is more than the product value), and what kind of price you're seeing for a whole sheet.

The only suggestions I could think of would be to try your local bearing/industrial supplier, or a shop that rebuilds car/truck automatic transmissions.

The last chain hoist I had apart was a poorly made $15 Chinese 1 ton unit. The brake disk in it had chips in it that looked like brass, and was a free floating disk (closer to 1/8" thick, about 4" in diameter, with maybe a 1" center hole)

WB ......... metalworking projects

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Reply to
Wild_Bill

On Fri, 24 Aug 2007 21:46:16 -0700, with neither quill nor qualm, Grant Erwin quickly quoth:

Ooh, looks like a fun and tasty tome. Hmm, which is better: Guillet's, Martin's, Sahag's, Myszka's, or Durley's version?

Check with a local brake shop who still makes their own product. They could either bond or rivet it for you, or sell you the friction material.

I've never even seen friction material for sale, so this is a SWAG.

-- Books are the compasses and telescopes and sextants and charts which other men have prepared to help us navigate the dangerous seas of human life. --Jesse Lee Bennett

Reply to
Larry Jaques

Grant; Not seeing the disc, Let me make some assumsions, the disk is glued/riveted to a metal backing plate. Is it double sided or single sided ? You say the disk is 3/16 thick, with a nonworn part of 1/4 thick. I think you have an adjustment issue. And it needs to be very free to move. Granted I haven't taken a chain fall apart in 20 years, but I don't think the old ones have changed. Most chain falls and hoists I have seen that use that type of friction lock, will wear down to the metal backing plate before they start to slip. If you have got a 1/16 more than the backing plate it should be OK. Shims have been used on some, but most just need to be adjusted. Most likely this hoist has seen a hard life, being dropped, run over ect, but not used that much. BTW hardwood will work as a friction material for about a year of hard use (don't ask ) And look at motorcycle clutches, you may be able to adapt one to fit, or even auto/truck clutch plates after removing the rivets (don't ask)

Good luck gary

Reply to
Gary Owens

I bet in the old days the friction material was heavy leather. With modern adhesives, especially urethane, one can face-glue multiple sheets to make the needed thickness, if a single piece cannot be obtained.

As for cutting, given that this is a one off, a scrollsaw or a coping saw and a jewelers bench pin

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could work.

Make up a full-scale drawing on paper, temporarily glue to stock, cut to line, remove paper.

Joe Gwinn

Reply to
Joseph Gwinn

My first thought is to check at your thrift/junk store for disc brake pads if they would be big enough. But obviously if you are thinking of using an knife blade to cut it, the material must be much different from brake pad material.

Dan

Reply to
dcaster

Some farm machinery use brake disk material in slip clutches. Maybe a dealer parts dept. could match up something.

Reply to
Ralph Henrichs

I think that there is something else involved besides just wear. Maybe something needs to be re-tensioned or a part is missing. I cannot see how you can get from a working hoist, to a hoist that does not hold the hook at all, with just wear, by using the hoist for lifting.

Or maybe this hook suffered a catastrophic failure? (Like load somehow falling and tearing the clutch or whatever). Is there any way to check the chain for elongation (like measure every link with a inside caliper and see if the lengths are consistent).

i
Reply to
Ignoramus3635

before it

somehow

I used one of those lever hoists last year to pull out some tree roots - worked well, but just as I was finishing the heavens opened and everything got drenched. As I brought in back indoors I gave it a liberal squirt of WD40 to chase the water off, and that was it's downfall - never managed to get it working again. I stripped it down, cleaned the clutch friction plate and pressure plates with acetone to get rid of the WD40, put it back together, adjusted it as per the manufacturers downloadeable docs, but it never would hold even it's own weight - never figured it out - even stripped & re-assembled it three times. Ended up slinging it out and buying a new one. (but I kept the chain & hook )

AWEM

Reply to
Andrew Mawson

How about a clutch/brake relining shop?

-Carl

Reply to
Carl Byrns

After all, oil immersed clutches in motorcyles - well certainly in the

1960's when I played with them - were just cork pads bonded to the plates.

AWEM

Reply to
Andrew Mawson

Brake pads on cars must work when they are very hot. I have used sheet cork as a brake pad in low speed cool applications.

Reply to
Usual suspect.

Grant, If you decide to make a new disc McMaster-Carr sells friction material on pg. 3380. 1/4" x 5" strip (6175K146) is $15.12 / ft. Paul

Reply to
Paul

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