Starter Motor End Float

John, I had a look on the Internet and found that 0.010" seems to be a more acceptable amount.

I am not sure what is proper, but it is not much (albeit still noticeable) and yet it must have some so when the car is toasty hot after a few hours of driving (heat sink) that it still works.

While going through my 810 starter motor I noticed that it has quite a bit of end float and in the region of 0.020"
There are some non conductive shims at the commutator end, so I probably need to fit some more.
So my question is, what is the allowable end float?
Thanks in advance ................. a Merry Christmas and Happy New Year to everybody out there.