An independent hex cap screw reference & spec library Compare Grades FAQs
Fastener Reference Library

Every hex cap screw
standard, in one place.

A plain-language guide to the specifications that govern hex cap screws — SAE J429 and the ASTM grades. Identify a grade, look up its standard, compare them all. Built by a fastener buyer, not a catalog.

Compare all grades Start with SAE J429
Grade 2
No markings
Grade 5
3 radial lines
Grade 8
6 radial lines

Head markings identify SAE J429 grade at a glance.

Browse by standard
Inch · carbon & alloy

SAE J429

The inch-series standard behind Grade 2, 5, and 8 hex cap screws.
Inch · low strength

ASTM A307

Baseline carbon-steel bolts and screws for general-purpose use.
Inch · high strength

ASTM A449

Quenched & tempered, strength comparable to SAE Grade 5.
Inch · high strength

ASTM A354

Alloy steel, Grades BC and BD — BD rivals SAE Grade 8.
All standards
Compare every grade side by side

SAE J429 and the ASTM grades in one master chart — head markings, size ranges, and headline strength values.