Joseph Gwinn fired this volley in news:joegwinn-
:

What
problems were they solving?


Pretty simple. The fact that they were roll pins somewhat suggests they
were NOT designed to be removed.

So, they were simply enforcing that the face of the friction washer would
be the ultimate yield point if something slipped, rather than having the
washer slip on the shoulder of the shaft.

Although my grinders have a mere shoulder, _I_ would rather have them
slip on the paper washer than to slip on the shaft -- if they ever
slipped; which they have not.

LLoyd