Gallery, Projects and General > How do I??

Making pulleys (sheaves)

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John Rudd:
If your driver is running at 2000rpm and the driven needs 3000, the ratio is 1:1.5
So the bigger 5" pulley is on the engine and the smaller 3.33" on the gen.

Speed adjustment on the engine will accomodate any size irregularity in the pulleys.....( governer?)

Jo:

--- Quote from: AdeV on April 10, 2017, 06:35:51 AM ---Thanks guys, what I'm after is: Is using the ratio of the OD of the pulleys generally regarded as "close enough" when sizing up?

--- End quote ---

Yes. (Assuming they are both for the same size belt)

Jo

AdeV:
Perfect, thanks  :thumbup:

Jo - yes, they'll be for the same size belt (probably "A" section twin groove).

So.. next question... as 10" pulleys cost ££££ (or $$$$, or even ¥¥¥¥), and are mostly cast iron & therefore heavy,  I'd thought I might cast my own out of aluminium. This appears to be quite an uncommon thing to do, at least for a home workshop, as one doesn't see many references to home-made pulleys. I did find one useful page here, but there's very little information given about machining the inside of the pulley grooves.

If anyone has any tips/tricks, please do share them, I'm all ears :D

mattinker:

--- Quote from: AdeV on April 10, 2017, 07:48:15 AM ---Perfect, thanks  :thumbup:

Jo - yes, they'll be for the same size belt (probably "A" section twin groove).

So.. next question... as 10" pulleys cost ££££ (or $$$$, or even ¥¥¥¥), and are mostly cast iron & therefore heavy,  I'd thought I might cast my own out of aluminium. This appears to be quite an uncommon thing to do, at least for a home workshop, as one doesn't see many references to home-made pulleys. I did find one useful page here, but there's very little information given about machining the inside of the pulley grooves.

If anyone has any tips/tricks, please do share them, I'm all ears :D

--- End quote ---

I've cast quit a few pulleys, I would not cast them as in the example you've shown. It is far simpler to turn the grooves afterwards. The pulley pattern in the photo below is one that I made early on, originally I split it, not a good idea, it needs taller molding boxes and is much more difficult to get out of the sand that way! simple flat forms are much easier to make and use!

All the best, Matthew

mattinker:
A passing thought, you probably know this, but Al has a shrinkage factor of 1.8%

Not a lot, but...............

Cheers, Matthew

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