Dowel Pins

Dowel pins are precision-ground cylindrical pins used to align and locate mating parts with high accuracy. Pressed into a reamed hole, they fix the relative position of two components and carry shear load. They are essential in tooling, dies, fixtures, machinery, and any assembly requiring precise, repeatable alignment. We stock dowel pins in hardened and stainless materials across the full size range.

How Dowel Pins Work

A dowel pin is manufactured slightly oversized for an interference (press) fit in one part and a slip or transition fit in the mating part. Pressed home, it precisely registers the two parts and resists shear, removing positional play that threaded fasteners alone cannot control. Hardened pins resist deformation and wear under repeated assembly.

Standard vs. Oversized

Standard dowel pins are ground to a precise nominal diameter for the initial press fit. Oversized dowel pins (typically 0.001"-0.002" larger) are available for re-pinning worn holes, restoring a tight fit without re-machining. Stock both to handle new builds and repairs.

Materials

Hardened alloy steel: through-hardened and precision ground, the standard for maximum durability and tight fits. 18-8 stainless: corrosion resistance for general environments. 416 stainless: hardenable stainless combining corrosion resistance with higher hardness.

Dimensional Standards

Inch dowel pins conform to ASME B18.8.2; metric hardened pins to DIN 6325 / ISO 8734, and unhardened to ISO 2338.

Selecting the Right Dowel Pin

Ream the hole to the correct tolerance for a proper press fit — too loose loses precision, too tight risks galling on installation. Choose hardened pins for tooling and repeated assembly, stainless for corrosion resistance. Use oversized pins to restore worn holes. Size the length so the pin fully engages both parts without bottoming or protruding.

Use the filters to narrow by diameter, length, and material.