On 07/11/2016 16:05, FranK Turner-Smith G3VKI wrote:

I remember the days of 'motorcycle tightness'. The procedure was to
tighten the first bolt until it sheared, then tighten the rest to a
quarter turn less.

Don't laugh...

A company had been contracted to build a spacecraft - it might have been
intended for Jupiter - and the structure was based on bolted-up
elements. Came the day for the first assembly, and as the
special-material bolts were tightened, they sheared. Puzzled, the
engineers stopped the assembly and checked the remaining bolts, their
spec, their audit trail, etc, but could find nothing wrong. Eventually
they worked out that the small amount of heating that resulted as they
were being given the final torquing-up was enough to reduce some
material property to a level the bolt could not sustain. They solved the
problem by tightening the bolts in very small increments and allowed
plenty of time for thermal re-equilibration.

--
Spike

We are not only our brother's keeper; in countless large and small ways,
we are our brother's maker.