On Mon, 14 May 2018 17:30:07 +1000, FMurtz
wrote:

snip

Yes but used high tensile and sometimes stainless threaded rod (can not
remember grade)

From my experience, most stainless fasteners seem to be pretty soft,
they certainly hand-saw / file pretty easily.

I found this interesting:

https://www.haguefasteners.co.uk/bol...0-9-12-9-14-9/

and

https://www.haguefasteners.co.uk/bs-...ded-fasteners/

https://en.wikipedia.org/wiki/ASTM_F568M

And then you get into the various levels of friction with the various
finishes on fasteners and therefore the torque v clamping force etc
etc.

Cheers, T i m