Spiral Pin, Heavy Duty, Metric Sizes
What Is a Heavy Duty Spiral Pin?
A spiral pin, known in metric fastener standards as a coiled pin, is rolled from a strip of hardened spring steel wound into a cylindrical shape rather than machined from solid stock. A heavy duty spiral pin is wound with roughly 2.25 turns of overlap, compared to about 2 turns on a standard duty spiral pin, giving a thicker effective cross section and higher shear capacity.
Like other coiled pins, the spring action of the wound strip presses continuously against the wall of a drilled hole once installed, which helps the pin resist working loose under vibration or repeated loading, and allows a degree of elastic compression when installed in a hole with normal tolerance variation.
Key Features and Benefits
- 2.25 Coil Wrap: thicker effective wall section than a standard duty spiral pin.
- Higher Shear Strength: suited to higher load fastening applications than standard duty coiled pins.
- Continuous Spring Pressure: grips the hole wall along the full length of the pin.
- Tolerant of Hole Variation: the coiled design compresses to accommodate normal drilling tolerance.
- Chamfered Ends: ease starting into a drilled hole.
Materials and Finishes
- Spring Steel: rolled and heat treated for consistent coil tension and shear strength.
- Plain or Zinc Plated Finish: options depending on the corrosion resistance needed.
Standards Compliance
- DIN 7343, Coiled spring pins, heavy duty
- ISO 8750, Coiled spring pins, heavy duty
Size Range and Availability
Available in a full metric size range, sold individually or in bulk quantities.
Related Categories and Products
Frequently Asked Questions (FAQs)
1. What is a heavy duty spiral pin used for?
It's used as a general fastening or shear pin in applications needing higher shear strength than a standard duty coiled pin can provide.
2. How is a heavy duty spiral pin different from a standard duty spiral pin?
The heavy duty version is wound with about 2.25 turns of overlap, versus about 2 turns on the standard duty pin, giving a thicker wall and higher shear strength.
3. How is a spiral pin different from a spring tension pin?
Both are coiled spring steel pins with the same basic design; the naming reflects which standard they're specified to, DIN for spiral pin and ISO/ASME for spring tension pin, and they are generally interchangeable by size and duty class.
4. Does a heavy duty spiral pin need a reamed hole?
No, like other coiled pins, it's designed to fit a standard drilled hole.
5. Can a heavy duty spiral pin be reused?
Yes, it can typically be removed and reinstalled without losing all of its holding force.
6. What sizes are available?
We stock a full metric size range, available individually or in bulk quantities.
