DIN 916 M10 × 40 Headless
DIN 916 M10 × 40 is a socket set screw, cup point with a 40 mm nominal length, on a M10 × 1.25 mm metric thread. A headless grub screw with a cupped end that digs into the shaft. Common for locking collars, pulleys and knobs onto shafts.
Dimensions
- Standard
- DIN 916
- Type
- Socket set screw, cup point
- Size
- M10 × 40
- Thread
- M10 × 1.25
- Length L
- 40 mm
- Socket size s
- 5 mm
- Drive
- Hexagon socket
- Head
- Headless
Nominal values in millimetres as published in DIN 916. Estimated weight 24.662 g per piece in steel (24.819 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.
Thread data
Full M10 thread pageOther lengthsDIN 916 M10
All M10 specificationsInterchangeability
DIN 916 is catalogued with ISO 4029 as its equivalent designation. Dimensions are compared field by field rather than assumed identical.
Choosing and fitting this size
DIN 916 M10 × 40 is a headless in M10, 40 mm long under the head, on a 1.25 mm coarse pitch. Mating threads should be a matching class nut or a tapped hole of the same nominal size.
Set screws are rated by surface hardness rather than tensile class — the common stock grade is 45H, which is hard enough to bite into a hardened shaft. Stainless set screws are not through-hardened and will not bite the same way, so they are a poor substitute where the point has to grip.
For a tapped hole, M10 × 1.25 mm takes a 8.75 mm tap drill, and the external thread's minor diameter is 8.47 mm — that is the section carrying the load, not the nominal M10 figure. Thread engagement of at least one times the nominal diameter is what lets the bolt fail before the thread strips.