Problem of the Stillson Wrench Available to Purchase

There seems to be some difficulty in understanding the basic principles underlying the working of the Stillson type of wrench, and the object of the present article is to elucidate these from considerations of elementary statics. It is found that such considerations suffice to give an explanation of the way in which the wrench works, and an attempt is made to give a measure of the efficiency of the wrench by deriving the “torque magnification factor.”