A dowel pin is a small, cylindrical piece of metal or wood that is used to join two or more pieces of wood or other material together. It is also known as a dowel rod. A dowel pin is usually slightly smaller in diameter than the holes it is being inserted into and has a smooth, slightly tapered surface. This allows it to be inserted into the holes easily and without damaging the surrounding material. Once it is in place, the dowel pin prevents the two pieces from moving relative to each other in any direction except along the axis of the pin. This makes them ideal for use in applications where precise alignment is required, such as in furniture construction or machine parts. Dowel pins are also often used as axles in toys such as cars and airplanes.