Dowel pins, also known as parallel pins, are machined to tight tolerances (+/- 0.0002 inches) and often used as precise locating devices in machinery.

Dowel pins come in a range of sizes and lengths, and are often made from hardened and ground steel for increased strength and durability. They can be solid or hollow, and may have features such as knurls or grooves to allow for trapped air to be ventilated.

One advantage of using dowel pins over other types of fasteners, such as screws or nails, is that they create a strong, precise, and invisible joint, without the need for screws or other visible fasteners. This can result in a cleaner and more aesthetically pleasing finished product.