BEARING FOR STEADY REST

[ACF]

I've been away from this forum for almost a year now, and it's good to be back. About a year ago John Stevenson showed us a steady made out of a big ball bearing. I acquired a nice sized new ball bearing to make one of these rests. The bearing had some radial "slop" in it, so I thought it was defective. When I checked in the machinery's handbook about ball bearings the "slop" gets taken up by the ID and OD press fits when the bearing gets installed. Being I had only a ID press fit I still ended up with some slop. Went back to the handbook and it looks as though what is needed is a double row angular contact ball bearing which is preloaded and isn't dependant upon mounting to take up the slop. I hate to spend a bunch of money for this bearing if it isn't going to work, so if anyone out there can verify this and help me out, it would be greatly appeciated.

Chris

[Evan]

All single row ball bearings have "clearance". Clearance is not related to precision. I don't see why this would matter on a steady rest.

[Forrest Addy]

I wouldn't call it "slop" because that implies negligent construction. It's "internal" or "radial" clearance necessary for the bearing's proper function. wihtout that small amount of clearance the bearing's thrust capacity would be greatly reduced and as you pointed out, dialation of the inner race from the press fit would take up the internal clearance and possibly "brinnel" the races.

A used preloaded pair of angular contact bearings would certainly do the job. They don't have to be spindle quality inless a high degree of accuracy in terms of roundness is required in the finished product.

Have you considered a pair of tapered roller bearings from the full floating axle of a light truck? You know, skinny ones? If you mount the bearings apex to apex and use an adjusting nut on the bearing cones you could adjust the preload to suit the work.

[Jim Hubbell]

The "large ball-brg. rest" I made for my Atlas 10 in. shows no decernable "slop" or radial play when in use. Pictures in arcive.