29-06-2018, 12:19 PM
Another consideration when taking accuracy into account is temperature, hence the need to re-tighten cylinder heads after every thing has expanded, a recommended torque setting in the automotive sense is really only a guideline to provide consistency and to insure a fixing is tightened to its recommended setting give or take a bit. Going back to my rigging days, part of a radio towers maintenance schedule is a 10% bolt tightness check, on one tower in Essex of an unusual construction the preferred method of tightness for the 1 inch thread diameter bolts was by means of a dimpled washer, the dimples on the washer were compressed by the nut until a 10 thou feeler gauge was just nipped, now working in thous on a inch bolt might sound a bit over the top and you may think the altermate torque setting has been achieved which may be true , but in really hot weather it was not unknown for the tower legs to expand enough to shear of the head of the bolt.