Torque and Thread

I marched into the open tool shed to inspect heavy fastening hardware. On the edge of a timber workbench, a cast-iron mechanic's vise was clamped tight around an oversized steel bolt. The lead screw presented an optimal test of helical mechanical advantage. I climbed a wooden stool, planted my heavy boots onto the weathered worktop, and addressed the rotating steel handle. Wedging my left arm's green cone against the lower ball end of the lever, I applied full forward torque. The threaded shaft rotated with a gritty metallic rumble, opening the serrated steel jaws by half an inch. The thread pitch is coarse, well-greased, and fully capable of maintaining compressive force under load.