UHMW-PE Suitability for Belt drive

[pzzamakr1980]

I would like to remake my belt drive and for testing purposes I would like to try a plastic because its super easy to machine and cheap. Online metal supply has something called ultra-high molecular weight polyethylene. Would this be suitable for my purposes. It would need to be strong enough to withstand the forces of the motor and acceleration and deceleration. I know pulleys are made out of plastic I just dont know what kind. Thx

[mxtras]

I think it would be fine for smaller motors - under 300 OzIn. UHMW is a bit pricier than HDPE and they handle the same. Look into HDPE as an optional material.

One issue is that HDPE or UHMW will not really hold torque on a threaded fastener - the threads will distort and eventually pull out if the material is threaded. Also, under loading the material will migrate away. It's decent stuff to work with but it does have structural limitations.

Scott

[surplusdealdude]

Originally Posted by pzzamakr1980 I would like to remake my belt drive and for testing purposes I would like to try a plastic because its super easy to machine and cheap. Online metal supply has something called ultra-high molecular weight polyethylene. Would this be suitable for my purposes. It would need to be strong enough to withstand the forces of the motor and acceleration and deceleration. I know pulleys are made out of plastic I just dont know what kind. Thx

I wouldn't advise it.

I 've worked with UHMW for about 10 years now (sell it on ebay dot com under this ID as well).

Anything above a low speed and UHMW will melt right down. As well, it's a very soft, slippery plastic - not the best thing for a belt drive.

Try something like Nylon instead - it's a lot tougher and not as slippery. A bit more trouble to machine, but not much.

[pzzamakr1980]

Thank you for the replies. Okay, so I can only find one auction for nylon that would be appropriate for what I need. The larger pulley has a diameter of 3 inches so I would need something larger by about 1/2 inch to have material for belt guides. I just purchased a piece of 80d urethane that would be the right size and a bit. Would that work? If not I have other uses for it since its only 5 bucks anyways. Thanks again

[surplusdealdude]

Originally Posted by pzzamakr1980 Thank you for the replies. Okay, so I can only find one auction for nylon that would be appropriate for what I need. The larger pulley has a diameter of 3 inches so I would need something larger by about 1/2 inch to have material for belt guides. I just purchased a piece of 80d urethane that would be the right size and a bit. Would that work? If not I have other uses for it since its only 5 bucks anyways. Thanks again

I don't have any direct experience with urethane, so I can't give you an answer except to say that it's got to be better than UHMW for this.

If you were looking at my auctions, you could send me an ASQ (Ask seller a question). I do have pieces of nylon round stock that are 3 1/2" of larger.

But, since you have the urethane, try it first and see if it works.

[ger21]

You can get it at McMaster-Carr.

[surplusdealdude]

Originally Posted by ger21 You can get it at McMaster-Carr.

Yes you can, if you want to pay 5-10 times the price for it that you can buy it from me for.;-)

[Geof]

If you looked into it a bit deeper I think you would find most plastic pulleys are a thermosetting phenolic based plastc; the rigid stuff that is often used for electrical components. It is a brown color and some types are made from compressed, resin impregnated fibers and you can see the weave pattern toehrs are either paper or wood powder filled. Stinkc to high heaven when machined and the dust is very irritating.

[RICHARD ZASTROW]

Geof, That sounds like the stuff timing gears for engines used to be made of. I had some fiberglass reinforced matl. to machine once. Stunk, required dust mask on face and itched like hell. One of those never again parts.

Have a great Thanksgiving (in Canada?)

Dick Z

[Geof]

Originally Posted by RICHARD ZASTROW Geof, That sounds like the stuff timing gears for engines used to be made of. I had some fiberglass reinforced matl. to machine once. Stunk, required dust mask on face and itched like hell. One of those never again parts. Have a great Thanksgiving (in Canada?) Dick Z

That is the stuff. Breath the dust regularly and you are a candidate for respiratory failure.

The Canadian Thanksgiving was a few weeks ago but thanks for the wish...you and anyone reading have good Thanksgiving. We benefit because the company phones go quiet so we can catch up on paperwork in the office.

[pzzamakr1980]

Marvelous, well I think I will rule out the fiberglass impregnated stuff then. If the urethane doesnt work I will get the nylon and give that a try. I did have a question about the uhmw being used for a gib material. If it is so slick wouldnt it be appropriate to use. Right now I'm having a bit of a problem with vibration and I guarantee its caused by the gibs since when looses no vibration, when tight vibration. I've tried a variety of lubes and nothing seems to completely rid me of the vibration. Would uhmw be ideal for this or should I stick to the old gibs that are there and try to find a lube that works. Thx again.

[surplusdealdude]

Well, I have no idea what a gib is, but I can tell you that UHMW is one of the most slippery plastics around (only delrin and teflon are slipperier). As long as it doesn't have to rotate around a shaft at more than about 150 RPM, it makes an ideal roller. Any higher speed, though, and you're looking at a heat build-up that will likely melt it.

If this item has to rotate at a high speed, what I usually do is bore out a section of the UHMW to accept a smaller bearing. It works quite well then.