DIN 127Spring lock washer

DIN 127 M8 Spring lock washer

DIN 127 M8 is a spring lock washer, sized for M8 bolts. A split helical spring washer intended to resist loosening. Worth knowing that independent testing has repeatedly found its locking effect is marginal once the joint is properly preloaded — for safety critical joints use a prevailing torque nut instead.

Dimensioned drawing — DIN 127 M8d2 16⌀8.1h 4
DIN 127 M8 — Spring lock washerNominal dimensions in mm · Not to scale
ThreadM8
Socket size s2 mm
Inside Ø d18.1 mm
Thickness h4 mm

Dimensions

Standard
DIN 127
Type
Spring lock washer
Size
M8
For bolt size
M8
Socket size s
2 mm
Total height h
4 mm
Inside diameter d1
8.1 mm

Nominal values in millimetres as published in DIN 127.

Other lengthsDIN 127 M8

All M8 specifications
M8

Choosing and fitting this size

DIN 127 M8 is a washer with a 8.1 mm inside diameter. It sits under a bolt head or nut to spread the clamping load; the inside diameter matches the bolt it is specified for, so the washer and fastener should always be ordered as a pair.

Hardness is the governing property rather than tensile strength: a 200 HV washer suits bolts up to class 10.9, while 140 HV washers are intended for class 8.8 and below. Using a soft washer under a high-grade bolt lets the washer deform before the bolt reaches its preload, which quietly loses clamping force.