A special head, the VG, was offered that contained a built-in tapping mechanism. This head was based on the ordinary variable-speed type (with reduction gearing), and offered speeds from 55 to 720 r.p.m. in low range and from 275 to 3600 r.p.m in direct drive. Tapping speeds could be set at any point in the low-speed range (but not, of course, in the higher) with sensitive operation by friction cones that allowed the all-important automatic reversal.