Torque versus load measurements were conducted on SA-193, Grade B-7 bolts to establish friction characteristics under dry and lubricated conditions, using strain gages with appropriate read-out. Similar torque-load ratio figures were obtained for a series of different size clamps, employing a Tinius-Olsen tensile testing machine for which suitable fixtures were designed and constructed.

With the data produced from these investigation and projected failure loads, it was possible to establish maximum torque limits which would fall within predetermined safety requirements. The equipment used in this investigation is explained and the calculations discussed.