STAINLESS STEEL FLAT WASHERS FOR BOLTS WITH SPRING PINS DIN 7349

Flat Washers for Bolts with Spring Pins DIN 7349 — Spring (or roll) pin assemblies work on interference fit rather than thread tension - the pin is driven into a hole undersized for its diameter and relies on the spring pressure of the slotted tube to stay put, which is a fundamentally different retention mechanism from a bolt and nut. DIN 7349 exists because that kind of joint still needs a defined bearing surface under the pin head or retaining collar, and a general-purpose flat washer selected purely on bore size does not guarantee the thickness relationship the pin assembly actually needs. Get that wrong and the pin can sit proud, seat incorrectly relative to the shank hole, or fail to retain properly against the clamped components - which defeats the point of using a quick-fit spring pin joint in the first place. These assemblies turn up most often in linkages, machinery pivots, and applications where a fast, non-threaded retention method is preferred over a nut and bolt, typically where the joint is not expected to carry significant tensile load. Because this is a bearing washer rather than a spring or locking device, material selection is mostly about the operating environment: mild steel with a plated finish is fine for dry, indoor machinery, while A2 (304-equivalent) stainless is worth specifying wherever the linkage is outdoors, washed down regularly, or exposed to moisture, since a corroding washer under a pivot point tends to seize or wear unevenly. A4 (316-equivalent) is rarely necessary here unless the equipment operates in a genuinely corrosive or marine setting. Choosing the right washer means starting from the spring pin and bolt geometry specified for the assembly, not the bore alone - confirm the pin diameter and its position on the bolt shank, and check the washer thickness against DIN 7349 rather than substituting a general DIN 125 or ISO 7089 washer, since the dimensional relationship here is purpose-built rather than generic.

FAQs
Can a standard DIN 125 washer be substituted for DIN 7349?
Not reliably. The thickness and bore relationship in DIN 7349 is specific to the spring pin bolt geometry, so substituting a general flat washer risks the pin not seating or retaining correctly.

Does this washer provide any locking or anti-vibration function?
No - it is purely a bearing surface; retention comes from the pin's interference fit, not from the washer.

How do I choose the correct DIN 7349 washer?
Match the washer to the bolt diameter and spring pin size specified for the assembly, and confirm the washer thickness is correct for the pin's position on the bolt shank.