On Wed, 6 Jun 2018 14:35:02 -0700 (PDT), misterroy wrote:

I like the sacrificial screw and the helicoil suggestion.
The enforcing the instruction does not work. They lack the experience to know how much force is too much. I was once busy keeping things safe at the forge and I could see a pupil working with a hacksaw. It was 8mm annealed silver steel he was cutting. I saw him hard at it between the pupils I was supervising at the forge. After about 25 minutes of him sawing, there was no-one to supervise at the forge, so I went to see him. He had made a 2mm deep cut, in 25 minutes of work. I had a go. I added very little to the cut, but I knew something was wrong. The only teeth on the hacksaw were in the last inch at the ends. In the middle there was not even a sign of teeth it was rubbed smooth.

Clearly had no idea how much work it should be, so not clear to them that it was
much more work than it needed to be...

My idea is to use thumbscrews -- the knurled fastener, not the torture device--
to limit the torque on the screw.


Thomas Prufer