Medium-Duty Keyless Drill Chuck

Medium-duty keyless drill chuck, 0.5-20mm in 22 sizes, on a slimmer body than the heavy-duty from 13mm up — 44mm across at 13mm against 49mm. Keyless here means self-tightening: the reaction torque of the cut drives the jaws closed, so the bit holds harder the harder it works, and there is no key to lose. The B or JT socket goes onto a matching male taper: a drill press spindle nose that carries one, or a Morse taper arbor for a lathe tailstock, mill spindle or boring machine. It is taper mount only, with no threaded nose, so it will not screw onto a portable drill spindle — it has to meet a matching taper. The 20mm size closes to 5mm, where the heavy-duty reaches 1mm. Tapers, capacities and dimensions are in the size chart below.