ASME B18.2.1 — Square, Hex, Heavy Hex, and Askew Head Bolts
Standard: ASME B18.2.1
ASME B18.2.1 defines the dimensions of inch-series square and hex bolts — head sizes, wrench flats, and thread lengths for hex cap screws and hex bolts.
What It Covers
- Hex and heavy hex bolt head dimensions
- Bearing surfaces and thread length rules
- Square head bolts
- Wrench and clearance sizes