DIN 931Hexagon headExternal hexagon
DIN 931 M20 × 50 Hexagon head
DIN 931 M20 × 50 is a hexagon head bolt with a 50 mm nominal length, on a M20 × 1.5 mm metric thread. Same head as DIN 933 but with an unthreaded shank under the head. The plain shank carries shear load, which is why these are preferred for structural steelwork and machinery frames.
Diameter20 mm
Length50 mm
Pitch1.5 mm
Socket size s30 mm
Head height k12.5 mm
HeadHexagon head
DriveExternal hexagon
Dimensions
- Standard
- DIN 931
- Type
- Hexagon head bolt
- Size
- M20 × 50
- Thread
- M20 × 1.5
- Length L
- 50 mm
- Socket size s
- 30 mm
- Head height k
- 12.5 mm
- Drive
- External hexagon
- Head
- Hexagon head
Nominal values in millimetres as published in DIN 931. Estimated weight 123.308 g per piece in steel (124.093 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.
Thread data
Full M20 thread pageDesignationM20 × 1.5 fine
Pitch1.5 mm
Major Ø20 mm
Pitch Ø19.03 mm
Minor Ø ext18.16 mm
Tap drillØ 18.5 mm
Other lengthsDIN 931 M20
All M20 specificationsInterchangeability
DIN 931 is catalogued with ISO 4014 as its equivalent designation. Dimensions are compared field by field rather than assumed identical.