Precision Ground Dowel Pins (Hardened Alloy & Stainless Steel)
In precision mechanical assemblies, component alignment is critical to preventing tolerance stack-up. Our Industrial Dowel Pins function as high-load reference points, restricting lateral movement and ensuring concentricity between mating parts. Unlike standard fasteners which allow for radial play, these pins are precision-ground to strict interference fits, effectively resisting high shear forces in transmission casings, injection molding dies, and automated assembly fixtures. We eliminate the risk of micro-movements that lead to premature bearing failure or misalignment.
- Tolerance: Ground to m6 (Interference) or h6 (Clearance).
- Hardness: Case hardened to 58-62 HRC.
- Material: Alloy Steel or 304/316 Stainless.
- Geometry: Double chamfered/radiused for insertion.
- Finish: Surface roughness Ra ≤0.4um.
- Compliance: Meets DIN 6325, ISO 8734, ASME B18.8.2.
Technical Specifications
Product Name
Parallel Dowel Pins / Straight Pins / Aligning Pins
Standards
DIN 6325 (Hardened), ISO 8734, ASME B18.8.2, DIN 7 (Unhardened)
Material
Alloy Steel: AISI 52100 (100Cr6), SCM435
Stainless Steel: AISI 303, 304, 316 (A2/A4)
Hardness (Core/Surface)
Alloy: 58-62 HRC (Case Depth 0.5-1.5mm)
Stainless: Work Hardened (Non-magnetic options available)
Tolerance Class
m6 (+0.008/+0.002mm), h6 (0/-0.008mm), or Custom OEM
Diameter Range
Metric: 1mm – 25mm
Imperial: 1/16″ – 1″
Surface Finish
Ground and Polished (Ra 0.2 – 0.4 m)
Certifications
ISO 9001:2015, RoHS Compliant, Mill Test Reports (MTC)
Fretting Corrosion & Galling
In high-vibration machinery, standard pins with rough surface finishes (Ra >0.8um) cause fretting corrosion or “cold welding” (galling) during disassembly, often destroying the host bore.
Surface Finish & Hardness Control
Our Hardened Dowel Pins undergo a multi-stage centerless grinding and lapping process to achieve a surface roughness of Ra ≤0.4um. Combined with a surface hardness of 60 HRC, this prevents plastic deformation of the pin and minimizes friction during press-fit installation, ensuring the pin survives repeated assembly cycles without damaging the fixture.
Pneumatic Lock in Blind Holes
For blind hole installations in engine blocks or hydraulic manifolds, trapped air can prevent proper seating. We offer Vented Dowel Pins (with a ground flat) to allow air to escape, preventing the “piston effect” that pushes pins back out after installation.
Optimized for high-volume size keywords identified in your CSV data: 1/4, 3/8, 1/2 dowel pin.
| Nominal Diameter (d) | Tolerance (m6 Standard) | Chamfer Length (c) | Crown Height (r) | Common Lengths (L) | Double Shear Strength (Approx)* |
| 1/4″ | +0.0001 / +0.0003″ | 0.025″ | 0.008″ | 1/2″ to 2″ | 10,500 lbs |
| 3/8″ | +0.0001 / +0.0003″ | 0.035″ | 0.012″ | 3/4″ to 3″ | 24,800 lbs |
| 1/2″ | +0.0001 / +0.0003″ | 0.045″ | 0.016″ | 1″ to 4″ | 44,200 lbs |
| M6 | +0.012 / +0.004 mm | 2.1 mm | 0.6 mm | 10mm to 60mm | 32 kN |
| M10 | +0.015 / +0.006 mm | 3.0 mm | 1.0 mm | 20mm to 100mm | 89 kN |
| M12 | +0.018 / +0.007 mm | 3.5 mm | 1.2 mm | 24mm to 120mm | 129 kN |
*Shear strength values are based on hardened alloy steel (DIN 6325). Safety factor required.
Hole Preparation (Reaming): Dowel pins require precise hole geometry. Standard drilling is insufficient. Drill slightly undersized, then use a machine reamer to achieve H7 tolerance for the hole. This creates the necessary transition or interference fit with our m6 pins.
Press Fit vs. Hammering: Never strike a hardened dowel pin directly with a steel hammer. This causes “mushrooming” of the head, changing the diameter and creating shrapnel hazards. Use a soft-faced mallet or an arbor press for controlled insertion.
Lubrication: Apply a thin film of anti-seize or machine oil to the pin before insertion. This reduces insertion force and prevents scoring of the host material (especially in Aluminum or Cast Iron).
Material Pairing: Avoid using carbon steel pins in aluminum blocks in corrosive environments to prevent galvanic corrosion. Specify 316 Stainless Steel Dowel Pins for these applications.
Related Products
FAQ
What is the difference between DIN 6325 and DIN 7 dowel pins?
DIN 6325 refers to hardened dowel pins (58-62 HRC) ground to an m6 tolerance, specifically designed for high-stress tool and die applications. DIN 7 refers to unhardened pins, typically ground to an h6 or m6 tolerance, suitable for lower-load pivots or hinge pins where shear strength is less critical.
What hole size should I drill for a 3/8" dowel pin?
For a standard interference fit, the hole must be reamed to 0.3745″ – 0.3750″ (for a 0.3750″ pin). A standard drill bit will create an oversized or out-of-round hole that will not securely hold the pin; reaming is mandatory for correct alignment.
Can I use stainless steel dowel pins for magnetic applications?
It depends on the grade. 300-series stainless steel (304/316) is generally non-magnetic but can become slightly magnetic after cold working. For strictly non-magnetic requirements in sensor or medical applications, solution-annealed stainless or specific non-ferrous alloys must be specified.
How do I remove a dowel pin from a blind hole?
If the pin does not have an extraction thread, removal is difficult and risks damaging the part. Design engineers should always specify a “through-hole” or use Internal Thread Pull Dowels (DIN 7979) for blind applications, which allow extraction via a screw and puller tool.
What is the shear strength of a 1/2 inch hardened dowel pin?
A standard 1/2″ hardened alloy steel dowel pin has a double shear strength of approximately 44,200 lbs (depending on the specific alloy). Engineers must apply a safety factor (typically 3:1 or 4:1) based on the dynamic nature of the load.