On 9/7/2013 8:33 PM, anorton wrote:

In practice I think both your estimates are overly optimistic. In this
tiny, fine thread, the clearance is usually a large fraction of the
total thread depth, so the threads just engage near the tips. Usually
the failure mode is that the tips round over instead of shearing off.
Optical equipment I work with sometimes has these tiny screws.

Ah ... good point. Another nugget of RCM knowledge. Bob