A precision dowel pin is a solid, straight cylindrical metal pin with a centerless ground finish. The cylindrical design features a chamfer on one end for easy insertion and assembly and a rounded radius on the other end. Typically manufactured to meet industry standards such as ASME B18.8.2, MS16555, MS16556, MIL-P-21143, DIN 7, DIN 6325, ISO 2338, and ISO 8734 for tight tolerances and exact fractional diameters and lengths, it is commonly used as a hinge, shaft, precise location device, or pivot to align or secure parts within a precision assembly or fixture.
A precision dowel pin can be engineered from materials like stainless steel, alloy steel, or other custom materials, such as brass and aluminum (these two being less common), and it comes in inch/imperial, metric, and Mil-Spec sizes. It can be configured as either slip-fit or press-fit, depending on whether the dowel pin needs to slide into the hole or be tightly secured. This pin is widely utilized across various industries, including aerospace, electric motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, and the military, among others. Its capabilities ensure accurate alignment, precise positioning, and secure fitting between components in many applications.
Precision Dowel Pins at MF Supply
Choose from the inch, metric or Mil-Spec precision dowel pins below to see available materials and sizes. Standard materials offered include alloy steel, brass and grades 18-8 / 300, 303, 316, 400, 416, A1, A2 & A4 stainless steel.
MF Supply is a leading supplier with expertise in precision dowel pins. We stock and source an extensive inventory including major brands and equivalents to Pic Design, WM Berg, Unicorp, Misumi, Unbrako, American Sockets, and Holo-Krome. We also supply equivalents and alternatives to major national catalog brands including Grainger, Mcmaster-Carr, and MSC Industrial.
Our catalog features a wide range of inch/imperial, metric, and Mil-Spec precision dowel pins, encompassing various styles, sizes, materials, and finishes. These dowel pins comply with stringent industry standards, including Mil-Spec (MS16555, MS16556, MIL-P-21143), DIN, ISO, and ANSI/ASME standards. Below, we have detailed the main styles and sizes of precision dowel pins available:
Precision Dowel Pins Styles & Sizes Available
Precision dowel pins styles include press-fit, slip-fit, standard, oversized, hardened and unhardened.
Press-Fit Precision Dowel Pins: Press-fit precision dowel pins, also known as interference fit dowel pins, provide a secure and immobile connection between parts, making them ideal for applications requiring minimal movement.
Slip-Fit Precision Dowel Pins: Slip-fit precision dowel pins, or loose/undersize fit dowel pins, are perfect for alignment purposes and allow for easy removal and reassembly, making them suitable for situations where parts need to be frequently disassembled and reassembled.
Standard Precision Dowel Pins: Standard precision dowel pins are the most common dowel pins used for most alignment needs and adhere to industry-standard dimensions and tolerances, such as ASME, DIN, ISO, and Mil-Spec standards.
Oversized Precision Dowel Pins: These dowel pins are slightly larger than the hole they are meant to fit into. This design ensures a tight fit, often requiring pressing or high force for insertion and removal.
Hardened Precision Dowel Pins: These precision dowel pins are heat-treated for extra strength and durability, which is critical in high-stress applications such as automotive or aerospace components.
Unhardened Precision Dowel Pins: Unhardened dowel pins are suitable for less demanding applications where the emphasis is on accurate alignment rather than enduring heavy loads..
Precision dowel pins are manufactured in inch, metric, and Mil-Spec sizes and in a range of materials, such as alloy steel and various stainless steel grades, to meet specific tolerance and fit requirements.
Inch precision dowel pins, compliant with ASME B18.8.2 standards, are available in standard diameters such as 1/8", 1/4", 1/2" and more. These pins exhibit tolerances ranging from +0.0001" to +0.0003" for precision slip-fit applications, and from +0.0000" to -0.0002" for press-fit applications. They are typically made from alloy steel, as well as stainless steel grades 18-8, 303, 316, and 416.
Metric precision dowel pins are manufactured in compliance with DIN and ISO standards, including DIN 7, DIN 6325, ISO 2338, and ISO 8734. These pins are available in diameters ranging from M1 (1mm) and M2 (2mm) to larger sizes like M20 (20mm), with typical tolerances such as h7 and m6. They are commonly manufactured from materials such as alloy steel and stainless steel grades A1, A2, A4, 303, 316, and 416.
Military specification (Mil-Spec) precision dowel pins, or ms precision dowel pins, which are domestically manufactured in the USA, are available in a range of standardized sizes that meet stringent requirements for defense and aerospace applications. These dowel pins conform to military specifications such as MS16555, which ensures a tight tolerance range for secure press-fit applications, and MS16556, which allows for slip-fit assembly. Additionally, MIL-P-21143 precision dowel pins are also available. Stock diameter sizes range from 1/32 inch (0.03125 inches) through 1 inch. Mil-Spec precision dowel pins are typically engineered from alloy steel and stainless steel grades 303, 400, and 416; and are available with DFARS certifications and full documentation upon request.
We offer custom precision dowel pins made to your exact specifications, including non-standard diameters, lengths, and exotic materials for highly specialized applications. We ensure you receive all required certifications, such as material certifications, lab test reports, heat treatment certifications, and a signed Certificate of Conformance upon request and for an additional fee.
Precision Dowel Pins Materials Available
Material selection is crucial for ensuring that precision dowel pins perform effectively in their intended application. The most commonly used materials in metal precision dowel pins include stainless steel, alloys, and exotic options. Below is a list of materials available for selection for precision dowel pins:
18-8 / 300 stainless steel: Precision dowel pins made of 18-8 / 300 series stainless steel offer excellent corrosion resistance and are ideal for environments where moisture exposure is limited. This makes them versatile for general-purpose applications, ensuring that components remain aligned and secure without significant risk of rust or degradation.
303 and 304 stainless steel: 303 and 304 stainless steel precision dowel pins provide excellent machinability, making them easy to manufacture to tight tolerances, which is especially beneficial when high volumes of pins are required.
316 stainless steel: 316 stainless steel Precision dowel pins offer superior corrosion resistance, making them ideal for use in harsh or corrosive environments, such as marine or chemical applications, where precision and durability are critical.
416 stainless steel: Dowel pins made from 400 or 416 series stainless steel offer high hardness levels after heat treatment, and provide increased wear resistance. This makes them well-suited for high-stress applications where strength and durability are essential.
A1, A2, and A4 stainless steel: Precision dowel pins made from A1, A2, and A4 stainless steel grades offer different levels of corrosion resistance and hardness, with A1 and A2 suited for moderate environments and A4 being optimal for highly corrosive conditions.
Alloy steel: Precision dowel pins engineered from alloy steel are valued for their strength and resistance to deformation, making them a perfect choice for heavy-duty applications.
Brass: Brass precision dowel pins offer corrosion resistance, non-magnetic properties, good electrical and thermal conductivity, ease of machining, and aesthetic appeal. They are often used when there’s a need to avoid sparkling or in applications with lower strength requirements.
Custom materials: Custom dowel pins can be made from exotic metals, such as brass and aluminum, and with special coatings, such as black lustre, bright microinch, ebony black Oxide, phosphate, and more, for specific needs. This ensures these pins can meet unique and specialized application demands.
What are the Features & Benefits of Precision Dowel Pins?
Precision dowel pins offer a wide range of features and benefits that make them indispensable in high-precision assemblies. Below we list six features and benefits of precision dowel pins:
Tight Tolerances and Precision: Precision dowel pins are manufactured with extremely tight tolerances, often within ±0.001 inches, ensuring accurate alignment and positioning of components in high-precision assemblies, such as machinery and robotics.
Durability: Made from materials like stainless steel and alloy steel, precision dowel pins offer high tensile strength, making them ideal for applications where durability and resistance to deformation are critical.
Corrosion Resistance: Many precision dowel pins are made from corrosion-resistant materials like 303 and 316 stainless steel, providing long-lasting performance even in harsh environments such as marine or chemical applications.
Versatility in Fit (Slip-Fit or Press-Fit): Precision dowel pins can be configured as slip-fit for easy insertion and removal, or press-fit for a secure, permanent connection. This makes them adaptable to various applications depending on the required fit.
Wide Range of Sizes and Standards: Precision dowel pins are available in both inch and metric sizes, and can comply with various industry standards such as ASME, DIN, and Mil-Spec, ensuring compatibility with a wide range of applications across different industries.
Customizable Options: Precision dowel pins can be custom-made to meet specific requirements, such as unique diameters, lengths, tolerances, or even special coatings and finishes. This flexibility makes them ideal for highly specialized or challenging applications.
Precision Dowel Pins Installation Steps
To ensure proper alignment and secure fastening of components, installing precision dowel pins demands meticulous attention to detail. Whether you are using slip-fit or press-fit dowel pins, correct installation is crucial for the stability and accuracy of your assembly. By following the six steps outlined below—from preparation and pin selection to alignment and inspection—you can achieve a precise and reliable installation.
Prepare the Components: Ensure that both the dowel pin and the components it will be inserted into are clean and free of debris. Verify that the holes are drilled to the correct size for either a slip-fit or press-fit installation.
Select the Appropriate Precision Dowel Pin: Choose the correct type of dowel pin for your application, considering factors such as material, size, and fit (slip-fit or press-fit). Make sure the pin meets the required tolerance and specifications for your assembly.
Align the Components: Position the components that will be joined by the dowel pin. Align the pre-drilled holes in each component to ensure accurate placement during installation.
Insert the Dowel Pin: For slip-fit dowel pins, gently slide the pin into the aligned holes. For press-fit dowel pins, use an arbor press or hammer to apply even pressure to drive the pin into place, ensuring it fits securely without damaging the components.
Ensure Proper Fit: After inserting the pin, verify that the pin is fully seated and that the components are securely aligned. Ensure that there is no excessive movement between the components.
Inspection: Inspect the assembly to confirm that the dowel pin is properly installed and the parts are securely fastened. For press-fit applications, ensure the pin has been driven to the correct depth without over-pressing.
With over 50 years of experience as a supply chain partner to manufacturers, and deep and broad expertise in fasteners, including precision dowel pins, MF Supply can help with all your fastening and hardware needs.
We work with the best-established factories in the United States and abroad to supply the most popular precision dowel pins, including exported, domestic (USA-made) press-fit, slip-fit, standard, undersize, oversized, hardened and unhardened dowel pins in inch/imperial, metric & Mil-Spec (MS16555, MS16556 & MIL-P-21143) sizes. Our large inventory includes precision dowel pins in alloy steel, brass, and in 18-8, 303, 316, 400, 416, A1, A2, & A4 series stainless steel materials. Our products are DFAR compliant with COC and full certifications available upon request.
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