[H. L. Chauvin]

Hi Duffer,

Never lost a bearing either, & also over 50 years ago was always told that a tiny amount of loose play was better than very tight.

Then after reading so many different tightening methods, I called Timken Bearing Co. several years ago & asked for a technical engineer to explain how to tighten Model A front wheel bearings.

FWIW: He said that:

1. If one tightens these conical bearings too much, the bearing races will begin to constantly rotate in the hubs until they get loose & can fall out. Then with loose races the hubs become loose.

2. He reiterated that these races are designed to be an "interference" fit; e.g. not tight enough to where they cannot rotate, but loose enough to rotate very slightly "on rare occasions"; but not loose enough to fall out and/or rotate constantly.

3. After properly installing the hub & tightening the nut, the in & out movement of the hub should be approximately seven thousanths (0.007) of an inch & that a very, very tight fit with absolutely no in & out movement can wear bearings & races in a short period & become a disaster.


After greasing the bearings, 0.007" movement in & out appears difficult to "feel", so if one wants to be about as accurate as a dentist making a crown for a tooth, one can use a dial caliper to measure 0.007" .............. Each to his own for accuracy.

Because the castellated nut always appears to be too tight for one cotter pin slot, & too loose for the other cotter pin slot, I ground down the back side of the nut with a grinder until it appeared to be positioned correctly when the cotter pin was inserted, then marked the nut's slot with typewriter correction white paint.

Amazing how long this white paint will last on a black painted nut -- furthermore, one does not have to later guess where to re-set the nut slot with respect to the cotter pin hole.

Hope this helps.