This page covers M42 Socket Head Cap Screws to ISO 4762 / DIN 912: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (ISO 4762 / DIN 912 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M42 Dimensional Row (ISO 4762 / DIN 912)
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Hex key s (mm) | Socket depth t min (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M42 | 4.5 | 63.0 | 42.0 | 32.0 | 21.0 | ISO 4762 / DIN 912 |
Spanner & Drive for M42 Socket Head Cap Screws
The hex socket for M42 Socket Head Cap Screws is shown in the spec table — use the matching Allen / hex key (an ISO 2936 hex key set covers the full range). A T-handle Allen key gives the best feel for setting preload by feel; for production work use a torque-controlled driver.
Common Applications for M42 Socket Head Cap Screws
M42 Socket Head Cap Screws are commonly specified for heavy assembly and large machine mounts.
Installation Tips for M42 Socket Head Cap Screws
- Use a quality Allen key fully seated in the socket — partial engagement is the most common cause of stripped sockets at this size.
- For countersunk and button-head variants, chamfer the through-hole to seat the head flush without preloading the head/shank fillet.
- At M42 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M42
For M42, pair with a M42 hex nut (ISO 4032 / DIN 934) and, where used, a M42 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
