View Full Version : Bearing dimensions?

01-22-2007, 03:17 AM
In attempting to build a motor, I've torn apart five CDrom motors, all with bushings instead of ball bearings. I've not been able to accurately measure the o.d. dimension needed for installing ball bearings in place of the bushings. It appears to be 7mm o.d, but I'd like to know for sure before I order some. Do you use flanged bearings so they won't move about? I've looked at several sites referenced here, but have not found such info.



01-22-2007, 05:52 AM
You need to purchase a dial caliper. Well worth the small investment if you intend to pursue modifying / building your own motors.

01-22-2007, 07:36 PM
yeah a good dial caliper is only maybe $20-$30. don't worry about flanged bearings. just apply a very small amount of epoxy or media CA to the OUTSIDE of the bearing. make sure you don't get any in the races and you'll be fine.

02-02-2007, 12:42 PM
If you have a Harbor Freight near you, go there. They seem to be always on sale like thier website.

02-02-2007, 03:26 PM
I own a caliper already, but I get an odd size reading inside the armature - about 6.92mm, which makes no sense. Maybe it's just insulation on the armature segments. Is it OK to scrape it off? Won't that compromise the amount of flux generated by the separate segments?

Anyway, I've decided to just build a complete new bearing holder and use suitable bearings. Lots of work, but it'll solve my problems.

Thanks for the suggestions!