One of several industry standard specifications for tapered tool shanks. Tapered shafts on tools engage with a recess of matching taper in a lathe, drill press, milling machine spindle or on a rotary table or similar tools. Tapers are precision-machined and when properly mated, free from oil and grit, hold the tool tightly and concentric to the machine spindle. Once mated, tools held by a taper must be removed by forcing them free by driving a soft shaft in from the rear of the tool, using a hammer or screw to apply force.