7/8-9 Flat Head Socket Cap Screws

7/8"-9 flat head socket cap screws in USS coarse (UNC) thread, made from heat treated alloy steel with a black oxide finish. We stock 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 6", 7", 8" lengths. They take a 9/16" hex key. Length is measured overall, including the head. Longer lengths are partially threaded (PT).

Specifications

Size: 7/8"-9 (USS coarse)
Lengths: 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 6", 7", 8"
Hex key: 9/16"
Tap drill: 49/64"
Material: alloy steel, ASTM F835
Finish: black oxide
Strength: 135,000 psi minimum tensile strength (ASTM F835)
Head: 82° countersunk

Common Uses

Flush mounting
Machine plates and slides
Fixtures

FAQ

What hex key fits a 7/8"-9 flat head socket cap screw?
A 9/16" hex key (Allen wrench).

What tap drill do I use for 7/8"-9?
Use a 49/64" drill for a standard 75% thread.

Are button head socket screws as strong as socket head cap screws?
No. Button and flat head socket cap screws are made to ASTM F835, with a minimum tensile strength of 145,000 psi in 1/2" and smaller and 135,000 psi over 1/2". Their smaller socket also takes less torque, so use a socket head cap screw for high loads.

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