Metric Dowel Pins, Spring Pins, & Precision Pins
Not sure which pin type you need for your application? Use this page to compare options, then request a quote when you're ready. You can also contact our office, and the RC Fastener team will gladly assist you.
What Are Metric Pins?
Metric pins are non-threaded fasteners designed for alignment and positioning rather than clamping. They locate two or more components relative to each other with a high degree of repeatability. Precision is the defining characteristic. Dowel pins, for example, are manufactured to tight diameter tolerances that determine whether they press into a hole or slip in and out during service.Choosing the right pin type depends on the application. You’ll want to assess the load direction, whether the joint needs to be serviceable, and how much shock or vibration the assembly will see.
Types of Metric Precision Pins
Dowel Pins (DIN 6325 / DIN 7)
Both DIN 6325 and DIN 7 are tight-tolerance dowel pins for permanent or semi-permanent alignment. The difference is material: DIN 6325 is through-hardened alloy steel, DIN 7 is A4 stainless for corrosive environments. Common in machinery, tooling, and structural assemblies.Pull-Out Dowel Pins (DIN 7979)
DIN 7979 pull-out dowel pins include an internal thread at one or both ends, allowing the pin to be extracted with a standard puller. They serve the same alignment function as standard dowel pins but are specified when the assembly needs to come apart for service or adjustment.Metric Spring Pins (DIN 1481 / ISO 8752)
Spring pins are slotted cylindrical pins that compress during installation and exert radial pressure against the hole wall. That outward pressure is what keeps them in place. They're used for vibration-prone applications where hole tolerances are less precise, since the pin self-adjusts to the bore. Available in carbon steel with black oxide finish and 420 stainless steel.Custom Metric Pins
RC Fasteners also supplies made-to-print precision pins for non-standard applications. We work with customers on custom dimensions, tight tolerance requirements, and specialty materials. Contact us to discuss your specifications.Dowel Pins vs Spring Pins
Dowel pins are rigid and hold position between the pin diameter and the hole. The pin doesn't flex or compress. What you get is a repeatable and fixed reference point between mating components.Spring pins work differently. The slotted body compresses on installation and pushes outward against the hole wall. That built-in flexibility lets them absorb shock and vibration without loosening, and they tolerate more variation in hole size than a solid dowel pin would.
In short: dowel pins for rigid and high-precision alignment. Spring pins for dynamic assemblies that need some give.
Metric Pin Standards and Fit Types
- DIN 6325 specifies through-hardened ground dowel pins with tight diameter tolerances. These are typically press-fit, meaning the pin is driven into a reamed hole and stays put without any additional retention.
- DIN 7 covers dowel pins in stainless steel to similar dimensional standards. Fit type depends on the hole preparation and tolerance class specified.
- DIN 7979 pull-out dowel pins follow the same basic dimensional profile as DIN 6325 but include a threaded extraction feature. The fit is press or transition, same as a standard dowel pin.
- DIN 1481 / ISO 8752 spring pins are installed into holes slightly smaller than the pin's nominal diameter. The pin compresses, and the spring action holds it in place. No press fit equipment required, which simplifies installation.
Materials and Performance Characteristics for Metric Pins
- Alloy Steel (Plain / Black Oxide): Through-hardened for strength and wear resistance. A common choice for most industrial applications.
- A4 Stainless Steel (316): Used in DIN 7 dowel pins. Strong corrosion and chemical resistance for food processing, marine, and outdoor environments.
- 420 Stainless Steel: Used in spring pins for applications that require both corrosion resistance and mechanical strength. Harder than austenitic grades like A4, which helps maintain radial pressure over time.
Order Metric Precision Pins from a Trusted National Fastener Distributor
If you need metric precision pins, RC Fasteners has you covered. We stock metric dowel pins, spring pins, and pull-out pins in accordance with DIN 6325, DIN 7, DIN 7979, and DIN 1481 / ISO 8752. Whether you need a one-off small-quantity order or repeat bulk orders, we can get you the right metric fasteners for your application, with fast turnaround times.Request a Quote or contact our team to get started.
