Sherline Lathe Headstock Hard Stop Kit 40116 Starting in August, 2015 every Sherline headstock now includes the holes to add an optional hard stop. The hard stop kit, P/N 40116 includes two steel rods and a knurled thumbscrew lock. The .242″ diameter steel rods are 4″ and 8″ long. A hole through the headstock base allows the hard stop rod to be set to contact the lathe table, providing a hard stop for the Z axis during turning operations.