Harry Bloomfield wrote:
Could someone kindly provide me with the figures for the loading at
which a 6mm ordinary mild steel rod will begin to stretch and one at
which it will break please, assuming room temperature? An answer in
kilogrammes would be good, just to settle an argument.

It will start stretching under *any* load, linear(ish) up to about 15%
at about four tons, and it will snap at just over 5 tons. A lot depends
on the end fastenings, though, as welding it to something will have an
unpredictable result on the strength of the bit affected by heat, and
the same goes for ultimate srength. Cutting a thread so you can tighten
it up with a nut will reduce the strength by a lot, depending on the
thread form. Strongest is hot rolled Whitworth, as it shouldn't have the
sharp, stress raising, corners of a cut thread.

--
Tciao for Now!

John.