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ToyMaker
07-06-2003, 09:50 AM
Has anyone used automotive wheel bearings (WB) in their home-made/converted machine?
Seems like a Mark I Mod 0 WB is designed to sustain loads that would crush a cnc machine :) . The only concern would be whether or not they have the needed axial and radial tolerances.
They aren't too big (the front WB in my VW bug was about 50 mm dia.) or too costly (I think I paid about US$7, although that was 10 years ago).

robotic regards,

Tom
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It is far better to buy a wonderful company at a fair price than a fair company at a wonderful price.
- - Warren Buffet, capitalist

HuFlungDung
07-06-2003, 11:56 AM
Hi Tom,

Are you referring to taper roller bearings or double row angular contact ball bearings? I've seen both types used in automotive wheel applications.

There should be nothing wrong with either type, if you understand how to mount them properly. The tapered roller type requires a preload applied either by a nut, or else super-accurate shimming of the bearings inside a captive housing.

If you build a proper preload system, you can be guaranteed that you won't have to settle for any backlash to the same degree as you get from using a single row ball bearing used as a thrust bearing. Standard ball bearings have quite a lot of endplay when the thrust direction is reversed.

Edit: on second thought, see this thread:

http://www.cnczone.com/showthread.php?s=&threadid=1117

ToyMaker
07-07-2003, 12:24 AM
The only ones I've had my hand on were tapered. And IIRC from the "Complete Dummys VW Survival Guide" were pre-loaded to something like 30 foot pounds.
A pillow block to hold them with pre-load should be easy to do. I was just wondering if it had already been done. And if it had, are there any hidden wedgies.

robotic regards,

Tom
= = = = =
I will tell you the secret of getting rich on Wall Street. You try to be greedy when others are fearful, and you try to be very fearful when others are greedy.
- - Warren Buffet, capitalist