Inch series · technical reference

Inch Socket Head Cap Screw Dimensions

Reference dimensions for inch-series hexagon socket head cap screws. The drawing uses an original CAD projection of a 1/4-20 UNC × 1 in reference instance; choose the exact UNC or UNF thread and L from the product listing.

StandardASME B18.3 · Inch Series
RevisionSource review · 2026-08
Unitsinches
CAD ORTHOGRAPHIC REFERENCEASME B18.3.1A · 1/4-20 UNC × 1 IN
CAD side orthographic view of an ASME B18.3.1A 1/4-20 UNC socket head cap screw
SIDE VIEW · LENGTH UNDER HEAD
CAD end orthographic view showing the hex socket of an ASME B18.3.1A 1/4-20 UNC socket head cap screw
END VIEW · HEX SOCKET

Model geometry is a 1/4-20 UNC × 1 in reference instance. Use the table for nominal-size data; confirm the listed product configuration before ordering.

Reference head dimensions · inch series
Nominal threadUNC / UNF (TPI)Head Ø AHead height HHex key J
#440 / 480.1830.1123/32
#632 / 400.2260.1387/64
#832 / 360.2700.1649/64
#1024 / 320.3120.1905/32
1/4 in20 / 280.3750.2503/16
5/16 in18 / 240.4690.3121/4
3/8 in16 / 240.5620.3755/16
1/2 in13 / 200.7500.5003/8
5/8 in11 / 180.9380.6251/2
3/4 in10 / 161.1250.7505/8

Reference dimensions for product selection. Confirm current ASME requirements and the exact product configuration before engineering release or installation.

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