Didn't want to hijack the other guy's step pulley thread, but I thought of a good question. I've got a set of the cheap cast step pullies. They're a bit wobbly, but functional. Is there a way to true them up? I don't have a lathe. Anything I can do?
-
The BladeForums.com 2024 Traditional Knife is ready to order! See this thread for details: https://www.bladeforums.com/threads/bladeforums-2024-traditional-knife.2003187/
Price is$300$250 ea (shipped within CONUS). If you live outside the US, I will contact you after your order for extra shipping charges.
Order here: https://www.bladeforums.com/help/2024-traditional/ - Order as many as you like, we have plenty.
Truing up or turning step pullies?
- Thread starter Jason Fry
- Start date
Nathan the Machinist
KnifeMaker / Machinist / Evil Genius
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Feb 13, 2007
- Messages
- 17,531
If this is one of those diecast zinc/aluminum deals, I know what you're talking about, I have them on my grinder. They were pretty bad.
A lathe wouldn't help much you unless you wanted to sleeve the thing, because you don't want to open up your hole, you're wanting to straighten it.
It seems to me this is the sort of thing that machinists used to be able to do, but you don't find as many today that do this much.
The process of scraping away the material that shouldn't be there, and shimming or upsetting material where you need it isn't something I can explain very well in this format, but yes, it can be done with nothing more than a file or narrow knife to scrape with, and shims. The trouble is, if you don't have a reasonably good surface for your shaft to bear against when you finish, or if your work is able to rock, you may find you make your problem worse.
Mine came with quite a lot of slop. Perhaps you could drive a small wedge in a couple strategic spots and reduce your wobble. A small nail hammered out flat would be a good wedge.
A lathe wouldn't help much you unless you wanted to sleeve the thing, because you don't want to open up your hole, you're wanting to straighten it.
It seems to me this is the sort of thing that machinists used to be able to do, but you don't find as many today that do this much.
The process of scraping away the material that shouldn't be there, and shimming or upsetting material where you need it isn't something I can explain very well in this format, but yes, it can be done with nothing more than a file or narrow knife to scrape with, and shims. The trouble is, if you don't have a reasonably good surface for your shaft to bear against when you finish, or if your work is able to rock, you may find you make your problem worse.
Mine came with quite a lot of slop. Perhaps you could drive a small wedge in a couple strategic spots and reduce your wobble. A small nail hammered out flat would be a good wedge.
The quality of most die-cast step pulleys is ... barely adequate. If you look around you can find machined steel step pulleys, but they are not cheap. If you can do with fewer speed choices, you could use a couple regular machined steel v-belt pulleys to take the place of the 3 step die-cast pulleys. Or you could buy a set of step pulleys with undersized bores and take them to a machinist to be bored for the size of your shafts. On the other hand, v-belt drives are very forgiving. Unless they are causing vibration and it is a problem you are looking to solve, slightly wobbly pulleys can run just fine for years.