One of the unique features of the Shopsmith is its method of speed control. Rather than multiple pairs of pulleys or an electronic speed control, the Mark V uses a Reeves-type continuously variable transmission consisting of two variable diameter pulleys controlled by a dial and worm gear. (Standard on the Mark V, this system was optionally available on the early 10ER machines.) Not only does this give theoretically infinite speed variation between the maximum and minimum speeds, it is also simple enough to be serviced fairly easily by a hobbyist. The new (as of 2010) Shopsmith Mark 7 uses a computer-controlled motor that offers more power, greater speed range, reversibility and easy conversion to 220 V.
