ISO 2009 M10 × 20 Countersunk head (90°)
ISO 2009 M10 × 20 is a countersunk head screw with a 20 mm nominal length, on a M10 × 1.25 mm metric thread. ISO equivalent of DIN 963, same 90° countersink.
Dimensions
- Standard
- ISO 2009
- Type
- Countersunk head screw
- Size
- M10 × 20
- Thread
- M10 × 1.25
- Length L
- 20 mm
- Head diameter dk
- 18 mm
- Head height k
- 5 mm
- Drive
- Slotted
- Head
- Countersunk head (90°)
Nominal values in millimetres as published in ISO 2009. Estimated weight 18.537 g per piece in steel (18.655 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.
Thread data
Full M10 thread pageOther lengthsISO 2009 M10
All M10 specificationsInterchangeability
ISO 2009 is catalogued with DIN 963 as its equivalent designation. Dimensions are compared field by field rather than assumed identical.
Choosing and fitting this size
ISO 2009 M10 × 20 is a countersunk head (90°) in M10, 20 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.
Common stock grades are 8.8, 10.9 and 12.9 in steel, plus A2-70 and A4-80 in stainless. Class 10.9 and 12.9 carry roughly 1.25 and 1.5 times the proof load of 8.8, but they also need a properly rated mating nut — a class 8 nut under a 12.9 bolt simply moves the failure into the thread. Zinc-plated 10.9 and above should be baked to avoid hydrogen embrittlement.
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.