What do I need to consider when choosing a locating pin?
Although dowel pins are available in a variety of materials and styles, there are a few major issues to consider when it comes to major commercial and mil-spec products.
Standard, extra large or small size?
Standard series dowels are used for initial applications. Their base diameter is 0.0002 inches higher than the nominal diameter. For example, a ¼ gauge pin has a diameter between 0.2501-0.2503.
Oversized series dowels are often used to fit into worn holes and are often used in the aftermarket for repairs. Their base diameter is 0.001" higher than the nominal diameter. For example, a ¼ oversized dowel has a diameter between 0.2509-0.2511.
Undersized series dowels are used for inconsistent holes. Their base diameter is -0.0002 inches below the nominal diameter. For example, an undersized ¼ pin has a diameter between 0.2500-0.2498. Mil-P-21143/2- falls into the undersized category.
End chamfer or radius?
Generally, commercial pins are manufactured in accordance with standard ANSI ASME B18.8.2. Standard alloy pins have a radius on one end and a chamfer on the other. However, stainless steel dowels are usually manufactured with chamfers on both ends.
Commercial or Military?
If you or your customers require domestic DFAR pins to meet the most stringent standards, military pins may be the best choice for you!
Alloy or Stainless Steel? Which stainless steel?
Alloy steel is the strongest pin available and is hardened. It can be finished with black oxide to provide better rust resistance than common alloys.
Type 416 stainless steel is the strongest standard stainless steel product and is the material used in the MS16555 and MS16556 series. Magnetic.
Type 18-8/303 stainless steel is the most commonly used stainless steel and is the standard material for the Mil-P-21143 series.
Type 316 stainless steel is the most corrosion resistant stainless steel available and is not associated with mil-spec parts.
