dowel pin

A dowel pin is a steel pin, typically cylindrical, used to keep machine parts in proper alignment or to fasten them together. These hardened and precisely shaped pins serve as location guides for adjacent machine parts and can maintain the alignment of components like punch and die sections.1

Another type of pin, the taper pin, offers a simple way to secure a gear or pulley hub to a shaft by driving the pin into a tapered hole that passes through both parts. Other pin fasteners include cotter pins, used to secure nuts and pins, and spring pins, which are split tubes that create a frictional locking grip through compression. Groove pins are solid pins with grooves that interfere with the hole walls when driven in. A "set pin" is also a term used synonymously with dowel.12