Hi

Reading a fellow member's misfortunes due to a poorly calibrated torque wrench ( commiserations) picqued my interest.

Torque settings - Are these derived from mathematical formulas, settings based on metals/thickness used , trial and error, etc - how does the factory produce the specs? Interest value only Cheers

There are recommended maximum torque figures for all threaded fasteners- based on thread size form & pitch, and fastener's steel spec.

The material it is threaded into (eg steel or alloy) varies the torque figure that can be applied.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Torque settings are found from a combination of the bolts size and the preload required for the joint, which itself is found from a combination of the thread stress area, the bolts proof strength (eg a 10.9 bolt has a proof strength of 830Mpa) all multiplied by a certain preload factor eg 0.75.

excellent answers thank you