Drift pin
In metalworking, a drift pin, drift pin punch, simply drift, is the name for a tool used for localizing a hammer blow. The tool is also used where we want the surrounding surfaces or areas to be protected from hammering. A drift pin is not used as a punch in the traditional sense of the term. Drifts are constructed with wood, light alloys, copper and even of steel. These are usually rods cut to size as for the job. Drifts can be used to remove dents from inaccessible places, for striking pins and keys out. A drift pin is constructed as a tapered rod, with the hammer acting on the large end of the taper. The tapered end of a drift pin is placed into the semi-aligned bolt holes of two separate components, and then driven into the hole. As it is driven in, the taper forces the two components into alignment, allowing for easy insertion of the fastener. Unlike most punches, force should never be applied to the tip of drift pin.
Drift pins are especially useful for aligning fastener holes in structural steel members. Spud wrenches used for assembling trusses and steel beams have tapered handles to use as drift pins.