A Buyer’s Guide to Dowel Pins

Dowel pins are a crucial component in many industrial applications, providing precise alignment and location within complex assemblies. Yet, selecting the right dowel pin for a specific application can be a challenging task, as there are numerous factors to consider. In this buyer’s guide, we will explore some of the key factors to keep in mind when purchasing dowel pins for industrial applications.

Diameter and Length 

The diameter and length of the dowel pin are the first critical factors to consider.  The diameter may be expressed as a fraction or a decimal. Typical stock sizes of precision dowel pins start at 1/16 diameter (.0625) and run to 1 inch.  Smaller or larger diameters are generally made to order with minimum runs and lead times. Larger diameters will generally provide greater strength and stability, but may be more difficult to insert and remove. Similarly, a longer dowel pin will provide greater alignment, but may be more difficult to install. It is important to select a dowel pin that is the appropriate size for the specific application.

Material

Dowel pins can be made from a range of materials, including 18-8/300 series, 316 or 400 series stainless steel, hardened alloy steel, aluminum, brass, and plastic.  The 3 most common available materials in inch are Alloy Steel, Stainless Steel 18-8/300 and 400 series stainless steel.  Metric dowel dowel pins are typically available off the shelf in Alloy Steel and A1/A2 stainless steel.  Each material has its own unique properties and advantages, so it is important to select the material that is best suited to the specific application. For example, stainless steel is often used in applications where corrosion resistance is a concern, while hardened steel is preferred for high-stress applications.  Generally, A1, A2 and 18-8/300 series stainless are unhardened and 400 series and alloy steel are hardened and will have a specified range of Rockwell hardness based on their DIN, ISO, ASME or Mil-spec specification.. Hardness may be expressed as case or core hardness.

Tolerance 

The tolerance of the dowel pin refers to the allowable deviation from the nominal diameter. Dowel pins with a tighter tolerance will provide a more precise fit and greater stability, but may be more difficult to insert and remove. It is important to consider the tolerance requirements of the specific application when selecting a dowel pin.  Precision pins will have a tolerance for their diameter and their length based on the specifications of the pin and whether it is standard, oversized or undersized.

Chamfered, Rounded or Flat  

Dowel Pins have 3 potential end styles, Chamfered, ROunded or Flat.  Each end may have a different shape.  The chamfer on a dowel pin refers to the beveled edge that is typically present on one or both ends of the pin. A chamfer can make it easier to insert and remove the dowel pin, and can also help prevent damage to the mating parts. It is important to consider the chamfer requirements of the specific application when selecting a dowel pin.

Surface Finish

The surface finish of the dowel pin can have an impact on its performance and durability. It may be expressed as a numerical number measure of Micro Max.  A smoother finish can reduce friction and wear, while a rougher finish may provide greater grip and prevent slippage. It is important to consider the finish requirements of the specific application when selecting a dowel pin.

Platings and Coatings

Platings such as Zinc, can be applied to dowel pins to improve their performance and durability. Common coatings include zinc plating, black oxide, and phosphate. Each coating has its own unique properties and advantages, so it is important to selecta dowel pin with the coating that is best suited to the specific application.

Quantity

The final factor to consider when purchasing dowel pins is the quantity required for the specific application. Dowel pins are often sold in bulk, so it is important to determine the required quantity in advance to ensure that there are enough pins available for the job.

Selecting the right dowel pin for an industrial application requires careful consideration of numerous factors, including material, diameter and length, tolerance, end style, surface finish, coating or plating, and quantity. By keeping these factors in mind, industrial purchasers can ensure that they select the dowel pins that are best suited to their specific needs, at the optimal price and availability, providing cost effective and precise alignment and secure fastening for their applications.

MF Supply is a WBE/WOSB certified supply chain partner to business, industry and government. We are sourcing experts and stocking distributors of Hardware, Precision & Mil-Spec Fasteners and Safety supplies. For more than 50 years, we have been supplying manufacturers in the electronics, industrial, commercial, aerospace and military markets with the full range of fastener products and services. Our Cage Code is 58QG4 and our registered name is RL Supply Inc dba MF Supply.