44. Slotted spring pins
A single-turn rolled pin, formed with one straight parallel slot. Slotted pins are economical and time saving as they can be installed in a single operation. The hollow design and slot give them their unique self-locking capabilities
45. Dowel pins
Dowel pins are often used as precise locating devices in machinery. Steel dowel pins are machined to tight tolerances, as are the corresponding holes, which are typically reamed. A dowel pin may have a smaller diameter than its hole so that it freely slips in, or a larger diameter so that it must be pressed into its hole