Hex bolt (DIN 931 standard)

This is a bolt with a hexagonal head, widely used in many fields.

DIN is a German industrial standard, and DIN 931 refers to a hex head bolt with partial thread (only part of the shank is threaded from the head side).

The area under the hex head has a stepped bearing surface (washer face).

Note: Thread length follows JIS-like reference standards:

When bolt length ≤ 125 mm:
 Thread length = (diameter × 2) + 6

When bolt length ≥ 130 mm:
 Thread length = (diameter × 2) + 12

When bolt length ≥ 220 mm:
 Thread length = (diameter × 2) + 25