"CarlBoyd" wrote in message
...
N_Cook wrote:
Is the torque release clutch there to make sure it is impossible to
strain
the mechanism by over tightening or is it to give results that are
repeatable if used by different people. ie below the torque release force
is
the area where grime/gummy lubricant etc would give inconsistent results
if
measurement was by feel of "first" touch.


Both

The former in the hands of idiots, and the later for all others.

CarlBoyd

Well said. I was taught at school to do three "clicks". When I got to work
and watched a machinist, I thought about it. After many years of practice, I
now know for sure who was right.

I recently measured a couple of hundred used pins from a large industrial
chain. These had some witness marks at the contact sites, but you couldn't
reliably estimate the wear from individual measurements across the worn and
unworn diameters. However by measuring everything (diameters in two planes
and four axial positions) and then doing the stats I was able to show that
the worn pins (only pins from some parts of the chain were worn) had on
average two tenths of wear on them. The diametral tolerance was about a
thou, and some of them had half a thou of taper.