<div class="section abstract"><div class="htmlview paragraph">THIS PAPER presents a mathematical analysis of clutch engagement under certain idealized conditions and the related experimental work. The analysis is divided into several cases concerning pure inertia load acceleration and inertia load with a superimposed “work” torque load.</div><div class="htmlview paragraph">The author also discusses the “wear in” process which occurs in some clutch materials, such as phosphor bronze mated to steel plates; the effect of grooving; and the static coefficient of friction.</div></div>