<VV> Re: spindle question

[djtcz at comcast.net]

There are rules about when and why a race is supposed to fit tight or loose.  Mostly its whether the load rotates relative to the bearing or not.
An electric motor with a horizontal shaft needs the bearings tight on the shaft, but the bearing ODs can be a slip fit in the motor end bells.   Conventional front wheel hubs are the opposite, and need the outer races genuinely tight to prevent creep.
The outboard inner race needs to be a slip fit (~0.001 inch diametral clearance)on the spindle to allow adjustment.  Because the load (car weight/gravity) is always one direction there is minimal tendency for the inner race to creep even with clearance.  If the outer race was a slip fit in the hub it would creep slowly as the wheel turned, and wear it and the hub.

Knurling a shaft to tighten a bearing fit is looking for trouble.  Even in a slip fit application the support needs to be 100%.  I've got an old "Ask Walt" bearing seminar with pictures of a bearing race with the knurl pattern fretted right into the race ID surface.  The right grade of loctite plus primer on degreased slightly worn parts is going to work for a long long time.

--
Dan Timberlake

-------------- Original message -------------- 
Bearing was not overly hot as it might be if too tight.  Believe that the 
inner race might be spinning on the spindle.  Will pull it apart tonight 
again to check, but does anyone have the dimensions for what the spindle 
diameter should be at the inner and outer bearing fits.

If the spindle is undersized and allowing the bearing to spin, any 
suggestions on a way to repair it ?  As a machinist we would sometimes knurl 
the shaft to raise it a thousandth or two to make the bearings lock down 
again, however not sure how hard the spindle surface is.  Don't think 
locktite would work too well because of all of the grease, but curious if 
others have used it and what their success rate was.