Considering Precision Dowel Pins for Your Next Project?
When you’re in the heart of the manufacturing industry, precision is not just a luxury; it’s a necessity. Components like dowel pins may seem small and inconsequential, but in this realm of precision manufacturing, they are paramount to ensuring accurate alignment and fit. Precision dowel pins, in particular, play an indispensable role in guaranteeing accurate alignment and secure fastening in a broad spectrum of applications. But with various tolerances, standards, materials, and sizes available, how do you make the right choice? It is important to know and understand these factors in order to make informed decisions that will meet your expectations & manufacturing needs.
What are Precision Dowel Pins?
At their core, precision dowel pins are simple cylindrical rods. The term “precision” implies that these pins are manufactured to very tight tolerances in order to ensure accurate fit in assemblies. Tolerances refer to the acceptable variation in dimensions from the specified value. The tighter the tolerance, the less variation there is—meaning that their dimensions are incredibly accurate. This precision ensures that dowel pins fit snugly into corresponding holes in two components, ensuring their exact/accurate alignment.
Standards & Tolerances
Several standards are followed in the production of precision dowel pins. The prevalent standard specifications come from the International Organization for Standardization (ISO), the Deutsche Industrie Norm (DIN), the American National Standards Institute (ANSI), and the Military Standard (MS/MIL-SPEC) of the United States. At a minimum, these standards specify the pin shape, and the diameter and length tolerance. These standards might also specify the pin hardness and surface finish. OEM branded dowel pins are handled separately and are addressed later in this blog.
ISO Standard:ISO 2338A & ISO 2338B (for unhardened pins) and ISO 8734 (for hardened pins) are common standards for dowel pins. Under these standards, precision dowel pins can be manufactured to either “M6” or “M5” tolerance classes, with “M6” being the more common of the two.
For example, an “M6” tolerance for a 5 mm dowel pin might have a diameter tolerance of -0.014 to 0 mm. So, the pin could be anywhere from 4.986 mm to 5 mm in diameter.
DIN Standard:DIN 7 (for unhardened, solid dowel pins) and DIN 6325 & DIN 6325H (hardened, solid dowel pins). Similar to ISO standards, the typical tolerance for precision dowel pins under DIN standards is designated as “M6.” This is the standard fit for dowel pins and ensures a tight fit that might require light pressing or can sometimes be hand-driven depending on the exact material and hole conditions.
For example, for a 5 mm dowel pin under the DIN 7 or DIN 6325 standard, the typical diameter tolerance might have and upper limit of 5.000 mm & a lower limit of 4.986 mm.
ANSI Standard: ANSI standard for dowel pins is ASME/ANSI B18.8.2. This standard defines sizes and tolerances for standard dowel pins, with the “Standard Series” being the most common.
For example, for a 1/4 (.25) inch interference fit diameter pin, the diameter tolerance might be +0.0002 to 0.000 inch. So, the pin diameter could be anywhere from 0.2500 inches to 0.2502 inches in diameter.
MIL-SPEC Standard: MIL-SPEC standard for dowel pins, particularly those conforming to MS16555 and MIL-P-21143 have very specific tolerances to ensure reliability and consistency in critical military and aerospace applications.
The MS16555 specifies a straight headless pin with a radius on one end and a chamfer on the other. The material can be Carbon or Alloy Steel or CRES 410 or 416 Stainless Steel. Available diameters range from 1/16 (.0626-.0628) through 1 inch (1.0003-1.0001). Lengths range from 3/16 to 6 inches long. Standard diameter tolerances are +.0002 over the nominal size.
The M21143 specifies a a straight headless pin made of CRES 303 Stainless Steel. The Mil-P-21143/1 series has a tolerance up to +.0002 over the nominal size. The M21143/2 series has tolerance of .0002 Under its nominal size.
Material Choices
Different applications may require Precision dowel pins made from different materials. The most common materials in the market include:
Stainless Steel: Offers corrosion resistance and is suitable for applications exposed to moisture or corrosive substances.
Alloy Steel: Known for its strength and durability, it’s ideal for heavy-duty applications.
Brass: Often used when there’s a need to avoid sparking or in applications with lower strength requirements (less common).
Aluminum: Lightweight and resistant to corrosion, aluminum precision dowel pins are suitable for applications where weight is a concern (less common).
Sizes Available
The diameter of precision dowel pins usually varies from 1/32″ to more than 1″, and their lengths span from 3/16″ to multiple inches. Hence, precision dowel pins come in a wide range of sizes, but certain sizes are more commonly used across various manufacturing applications due to their adaptability and compatibility with standard components. Selecting the appropriate size for your specific application is essential for achieving a snug fit, best performance, cost-effectiveness, and durability.
OEM Branded Precision Dowel Pins
Precision Dowel Pins – OEM branded “Precision” dowel pins are manufactured by precision component brands such as Pic Design, WM Berg, Unicorp and others who have their own technical specifications and are not governed by DIN, ISO or ANSI / ASME standards. They are usually only offered in stainless steel through distributors of precision components.
What to Consider Before Buying
Tolerance: Precision dowel pins have tight tolerances. Ensure that the pins you buy meet the specific tolerances required for your application.
Environment: Consider the environment in which the pins will be used. If they’ll be exposed to corrosive substances or high temperatures, material choice becomes crucial.
Custom Needs: If your application requires non-standard sizes or materials, you might need custom-made precision dowel pins.
Quantity: Depending on the scale of your manufacturing, you may need precision dowel pins in bulk. Purchasing in larger quantities often results in cost savings!
Supplier Reputation: Always source your precision dowel pins from reputable suppliers known for their quality and consistency.
Precision Dowel Pins at MF Supply
MF Supply is a WBE/WOSB woman owned business, and a trusted supplier of Functional Equivalents, including precision dowel pins, to OEMs, manufacturers, industry, and government. We are precision dowel pin experts, offering the full catalog of dowel pins in Inch, Metric, Military and OEM branded options in a wide selection of materials, sizes and specifications. As stocking distributors, many precision dowel pins are available and ready to ship today from our national distribution centers.
Browse through the links provided below to find the precision dowel pins that you need:
Mil-Spec Precision Dowel Pins: The full range of commercial and MIL-SPEC parts (M21143, MS16555, MS9390), including parts that are USA made, DFARS and ROHS compliant.
Inch Precision Dowel Pins: inch sizes to ASME ANSI B18.8.2 standards in alloy steel, stainless steel 18-8, 316, 400 series and hardened. Domestic and Imported options are available.
Metric Precision Dowel Pins: Metric sizes including DIN 7, DIN 6325, and ISO 2338 and 8734 in alloy steel, A2 & A4 stainless steel
Precision Series and OEM branded equivalents to PIC, BERG, both Inch & Metric precision dowel pins including Press-Fit A, B and Slip-Fit C series and all MD series pins in 416 and 303 stainless steel.
Please send us a Request for Quote for any other dowel pins not listed.
If you have additional questions or need help in selecting the right precision dowel pins for your next project, don’t hesitate to reach out to us or send us a quote request. Our team of sourcing experts is always ready to assist you on your journey to manufacturing excellence. “Finding the right screw for you” is our tag line after all!
Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.
Six Reasons To Buy From MF Supply
Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online. We are adding items and improving functionality daily!
Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers.
Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.
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.
At MF Supply, we have a large selection of Precision Dowel Pins and Mil-Spec Hardware. The product we want to highlight today is the MS16555 Dowel Pin.
What is the Mil-Spec Dowel Pin MS16555?
The MS16555 is a stainless steel, cylindrical, solid, and headless fastener. The MS16555 is classified as a Mil-spec fastener, made to a specific exacting standard that defines in detail, the screw’s attributes, including: dimensions, tensile strength, hardness, threads, drive type, material qualities and plating, just to name a few. Mil-spec is the informal name for the military standard the U.S. Department of Defense uses in the production of military equipment. Mil-spec fasteners are usually designated by an AN, MS, NAS or NASM prefix followed by a part number. Each of these prefixes is an abbreviation: NAS stands for National Aerospace Standard and MS stands for Military Standard.
Dowel Pin Uses
Dowel pins are broadly used in various applications, including aerospace, electrical motors, hydraulic equipment, instrumentation, and more.
They’re used as a hinge, shaft, or pivot, and are used to locate or hold parts together within a precision assembly or a fixture, often when things are moving within that assembly.
MS16555 Dowel Pin Options
The MS16555 series is classified as a press fit style dowel pin with a diameter tolerance -0/+ .0002 over nominal size. These Mil-spec dowel pins are DFAR & RoHS compliant & may be requested with manufacturers COC & Full material certifications.
Diameters range from 1/16 (.0626-.0628) through 1 inch (1.0003-1.0001). Lengths range from 3/16 to 6 inched long. For price and availability, send us an RFQ directly from our product pages.
Why Choose MF Supply for MS16555 Dowel Pins?
The MS16555 Dowel Pin is our most popular military spec dowel pin
They are made in the USA and are DFAR compliant.
Certification paperwork is available.
We have extensive stock, in NJ and at our distribution centers, which means no delay in delivery.
Learn More About MF Supply and our Products
We are excited for you to know that some products lines including CRES series MS16555 are available for purchase on-line. Additional dowel pin & mil-spec resources include:
We stock a huge selection of Mil-spec fasteners in both Alloy & Stainless Steel with full DFAR & RoHS paperwork. Factory drop ship available for thousands of parts!
If you are interested in learning more about these dowel pins or any of our other fasteners or PPE, contact us today!
Book a one-on-one consultation with our President, Robin, to discuss how MF Supply can help you solve your Industrial Sourcing, Fastener, and Safety concerns.
Six Reasons To Buy From MF Supply
Full eCommerce Enabled Website With Technical Manual Available 24/7 – Visit our website and Create a New Account, track online orders, browse our product catalog, check technical specs, subscribe to our blog, or buy online. We are adding items and improving functionality daily!
Same Day Shipping From The USA – Our hardware products are in stock and ship to you directly from our USA based distribution centers.
Functional Equivalents To Expensive Brand Names- We stock and source alternatives to brand name fasteners, reducing long lead times and saving you money.
Creatively Solve Problems – We are sourcing experts, offer competitive pricing and specialize in finding hard to find parts and reducing long deliveries.
One-Stop Shopping On Certified Hardware – We stock and source a full line of fasteners including Mil-Spec, DFARS compliant and other industrial products.
WBE/WOSB Woman Owned Certified Small Business – To meet your diversity & set-aside needs.
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.
Welcome back to our “what the heck is that” series, where we discuss some of the unique fasteners and electronic hardware that manufacturers use in the design and assembly of their products. Today, we will introduce you to the Dowel Pin.
What is a Dowel Pin?
If you have ever shopped at Ikea or assembled furniture on your own, then you are familiar with the peg shaped non-threaded wooden pins that are used to join parts together, aka as a Dowel Pin.
For the purposes of manufacturing, Dowel Pins are solid, headless cylindrical shaped straight metal pins with a centerless ground finish. Typically hardened and manufactured to precise fractional diameters and lengths, Dowel Pins come in a variety of sizes, styles, designs and materials that cause confusion among buyers, engineers and end-users alike! Today, we will try simplify this confusing category of fasteners.
Who uses Dowel Pins?
Dowel Pins are used as a hinge, shaft or pivot to locate or hold parts together within a precision assembly or a fixture.
They are broadly used across various applications in many industries, including: aerospace, electrical motors, hydraulic equipment, instrumentation, tooling and fixtures, machinery, military and many more.
Dowel Pins are popular within assemblies since they can withstand frequent insertion and removal without distortion. And production favors pins since they require no extra fastening hardware for insertion, no secondary operations and no mating parts. All this adds up to speedier production, which makes everyone in the food chain happy!
What do I need to consider when selecting Dowel Pins?
Although Dowel Pins are offered in a multitude of materials and styles, when it comes to the main commercial and Mil-spec offerings, there are a few main issues to consider.
Standard, Oversized or Undersized?
Standard series Dowel Pins are used for initial applications. They have a basic diameter 0.0002 inch over the nominal diameter. For example, a ¼ standard dowel will have a diameter between .2501-.2503.
Oversized series Dowel Pins are usually used to fit into worn holes and are generally used in the aftermarket for repairs. They have a basic diameter 0.001 inch over the nominal diameter. For example, a ¼ oversized dowel will have a diameter between .2509-.2511.
Undersized series Dowel Pins are used for inconsistent holes. They have a basic diameter -0.0002 inch under the nominal diameter. For example, a ¼ undersized dowel will have a diameter between .2500-.2498. The Mil-P-21143/2- falls into the undersized category.
Chamfer or radius on the end?
In general, commercial pins are made to inch standard ANSI ASME B18.8.2. Standard alloy pins will have a radius on one end and a chamfer on the other end. However, stainless steel Dowel Pins are often manufactured with a chamfer on both ends.
Commercial or Military?
If you or your customer needs domestically made, DFARs pins to the most exacting standards, then military may be the right pin for you!
Alloy or stainless? And which stainless for that matter?
Alloy Steel is the strongest pin available and is hardened. It can be finished with Black Oxide to provide greater rust resistance than plain alloy.
Type 416 Stainless steel is the strongest standard stainless steel offering, and is the material used for MS16555 and MS16556 series. Magnetic.
Type 18-8/303 Stainless Steel is the most commonly available stainless offered and is the standard material offered for Mil-P-21143 series.
Type 316 Stainless Steel is the most corrosion resistant stainless available and does not correlate to a Mil-spec part.
Are there other factors to consider?
Dowel Pins often show up under their Mil-spec numbers, which can be crossed to commercial equivalents. Some common Mil-spec series for Dowel Pins include Mil-P-21143 (303 Stainless), MS16555 (standard series offered in both alloy and 416 Stainless Steel) and MS16556 (oversized series offered in both alloy and 416 stainless steel).
If you are not ordering by an MS or NAS Mil-Spec part number, then inch Dowel Pins conform to ANSI/ASME B18.8.2. For commercial pins, be mindful to specify the material and size tolerance that you need. Unless noted, Dowel Pins are precision ground, hardened and heat treated to meet the proper Rockwell hardness.
And remember, no hammers! When installing Dowel Pins, never drive the pin into the hole with force, always press it in for best results.
Dowel Pins at MF Supply
We offer:
The full range of commercial and mil-spec parts, including parts that are DFARS and ROHS compliant.
Brand names and generic equivalents.
Custom made parts per print in non-standard and exotic materials and finishes.
Inch and Metric sizes including DIN 7, DIN 6325, and ISO 2338 and 8734