9/16" bolt torque

Tighten a 9/16-12 UNC grade 5 bolt to 109 ft-lb (147 N·m) with dry threads, or 82 ft-lb when lubricated. Grade 8 takes 154 ft-lb and grade 2 takes 70 ft-lb.

Calculated from SAE J429 and ASME B1.1. Updated 5 October 2026.

Grade 5, UNC, dry threads

109ft-lb

147 N·m or 1,305 in-lb

Grade

Thread

Threads

Unit

Torque dialBands mark each grade at dry torque

9/16" torque by thread and grade

Tap a row to show it on the dial. The unit switch above changes every value on this page.

9/16 inch bolt torque by thread series and SAE grade
Thread and grade	Dry torque	Lubricated	Clamp load	Proof load
9/16-12 UNC Grade 2	70 ft-lb	53 ft-lb	7,505 lbf	10,007 lbf
9/16-12 UNC Grade 5	109 ft-lb	82 ft-lb	11,599 lbf	15,465 lbf
9/16-12 UNC Grade 8	154 ft-lb	115 ft-lb	16,375 lbf	21,833 lbf
9/16-18 UNF Grade 2	78 ft-lb	59 ft-lb	8,373 lbf	11,164 lbf
9/16-18 UNF Grade 5	121 ft-lb	91 ft-lb	12,940 lbf	17,253 lbf
9/16-18 UNF Grade 8	171 ft-lb	128 ft-lb	18,268 lbf	24,358 lbf

Clamp load is 75 % of proof load. Dry: K = 0.20. Lubricated: K = 0.15.

9/16" at a glance

Wrench, drill and thread data for the same bolt.

9/16-12 UNC hex cap screwProportions to scale

Threads: 9/16-12 UNC
9/16-18 UNF
Stress area A_s: 0.1819 in² UNC
0.2030 in² UNF
Wrench / socket: 13/16"
Major diameter: 0.5625" 14.29 mm
Tap drill, UNC: 31/64 0.4844"
Tap drill, UNF: 33/64 0.5156"
Head markings: Grade 2 plain Grade 5 three radial lines Grade 8 six radial lines

Before you tighten

Lubricant changes the number

Oil, moly paste or anti-seize lowers the nut factor K, so the same torque produces far more clamp load. Use the lubricated value whenever the threads are oiled, or the bolt can yield.

Tighten in a star pattern

On flanges and covers, bring every bolt to about 30 %, then 70 %, then full torque, crossing the pattern each pass. Finish with one round at full torque in sequence.

Give the thread enough grip

Engage at least one diameter of thread in steel, about 1.5 diameters in cast iron and 2 diameters in aluminium, or the internal thread strips before the bolt reaches its clamp load.

These are general starting values for steel bolts in steel nuts or tapped steel. When the equipment, gasket or fastener maker publishes a torque, use theirs. Never reuse torque-to-yield bolts.

How the number is worked out

The 9/16-12 grade 5 figure, step by step.

T = K × F × d

K: 0.20, nut factor for dry plain steel
F: 11,599 lbf, 75 % of the 15,465 lbf proof load
d: 0.5625 in, nominal diameter

T = 0.20 × 11,599 × 0.5625 = 1,305 in-lb = 109 ft-lb

Where the inputs come from

Proof strength is taken from SAE J429: 55,000 psi for grade 2 at this size, 85,000 psi for grade 5 and 120,000 psi for grade 8. Multiply by the tensile stress area to get the proof load.

The stress area comes from ASME B1.1: A_s = 0.7854 × (D − 0.9743 / n)². Target clamp load is 75 % of proof load.

Lubricated values use K = 0.15. For other coatings or preload targets, use the torque calculator.

Other inch sizes

1/4"5/16"3/8"7/16"1/2"9/16"5/8"3/4"7/8"1"

Common questions

What is the torque for a 9/16 grade 5 bolt?

About 109 ft-lb dry for 9/16-12 UNC and 121 ft-lb for 9/16-18 UNF, based on 75 % of proof load.

What is the torque for a 9/16 grade 8 bolt?

About 154 ft-lb dry for 9/16-12 UNC and 171 ft-lb for 9/16-18 UNF.

What is the torque for a 9/16 grade 2 bolt?

About 70 ft-lb dry for 9/16-12 UNC.

What size wrench fits a 9/16 bolt?

A standard 9/16" hex cap screw takes a 13/16" wrench or socket.