DIN 7343 Coiled Spring Pins (ISO 8750)
Coiled spring pins are wound from spring strip through roughly two and a quarter turns, so the whole section flexes when the pin is driven and the load spreads evenly around the coil. We supply them in carbon steel and stainless steel, available in light, medium and heavy duty grades - metric diameters run from 0.8mm to 20mm with lengths from 4mm to 120mm depending on diameter, and imperial sizes from 1/32in to 3/4in are available alongside the metric range.
Also known as: spiral pin, coiled roll pin, coil pin, coiled tension pin, iso 8750, din 7343.
DIN 7343 (ISO 8750) dimensions
| Nominal diameter (medium duty, metric) |
|---|
| 0.8mm |
| 1.0mm |
| 1.2mm |
| 1.5mm |
| 2.0mm |
| 2.5mm |
| 3.0mm |
| 3.5mm |
| 4.0mm |
| 5.0mm |
| 6.0mm |
| 8.0mm |
| 10.0mm |
| 12.0mm |
| 16.0mm |
| 20.0mm |
Materials & strength
Uniform flexing, shock absorption
Because the coiled section flexes as a whole rather than at a single slot, stress distributes around the pin - the design absorbs shock and reversing loads better than a slotted pin of the same size.
Three duty grades
Light-duty (ISO 8751), medium-duty (ISO 8750) and heavy-duty (ISO 8748) coiled pins are separate standards, differing in the gauge of strip used. Medium duty is the general-purpose choice; light duty suits weak or brittle host material; heavy duty gives extra strength where the assembly can take the higher insertion force.
Hole matches nominal size
The recommended hole equals the nominal pin diameter within a tight tolerance band - a plain drilled hole, no reaming, with chamfered pin ends leading the insertion.
Related specificationsWhat is the difference between a coiled and a slotted spring pin?
A slotted pin is a single-thickness rolled cylinder with an open seam; a coiled pin is wound through multiple turns of lighter strip. The coiled form flexes across its whole section, which gives better shock absorption and a gentler radial load on the hole.
Which duty grade should I use?
DIN 7343 covers the medium-duty coiled spring pin, equivalent to ISO 8750. Light-duty (ISO 8751) and heavy-duty (ISO 8748) coiled pins are separate standards — we supply all three duty grades. Send us your requirement and we will confirm the right specification.
Are imperial sizes available?
DIN 7343 / ISO 8750 covers metric diameters 0.8mm to 20mm. Imperial sizes are available to commercial specification — send us your inch diameter and length requirement.
Any special care fitting coiled pins?
No special tooling is needed - they can be hammered or pressed in. When fitting into a punched hole, insert the pin from the same side the punch entered so the pin follows the cleaner edge of the hole.
Need DIN 7343 (ISO 8750) in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.