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Inch torque chart (SAE J429)

Target preload and estimated tightening torque for SAE grades 2, 5 and 8 across the Unified series - including the numbered sizes and the diameters above 1-1/2 inch, which J429 does not grade and which are marked as undefined here.

Inch torque chart (SAE J429)

99 sizes · ThreadRef · free sample of 8 representative sizes

Inch torque chart (SAE J429). Target preload and estimated tightening torque for SAE grades 2, 5 and 8 across the Unified series - including the numbered sizes and the diameters above 1-1/2 inch, which J429 does not grade and which are marked as undefined here.
SizeStress area
in²		Gr 2 preload
lbf		Gr 2 torque
lb·ft		Gr 5 preload
lbf		Gr 5 torque
lb·ft		Gr 8 preload
lbf		Gr 8 torque
lb·ft
UNC - Unified coarse
1/4-20 UNC0.031813135.520258.4285012
5/16-18 UNC0.0524217511333817472525
3/8-16 UNC0.0775318820495031697544
1/2-13 UNC0.141958504990757612750106
5/8-11 UNC0.2269300971440015020325212
3/4-10 UNC0.3345138001732130026630075376
UNF - Unified fine
1/2-20 UNF0.16660055102008514400120
3/4-16 UNF0.373153751922377529733600420

Proof loads per SAE J429, which steps down with diameter. Preload is 75% of proof load; torque is the T = K · F · d estimate at K = 0.20 (dry / as-received steel).

Torque figures are estimates that depend on the stated nut-factor assumption. Verify against your fastener manufacturer's data and joint requirements before assembly.

Every figure on this chart is also free on its own size page - tap any size in the first column to open it, or browse the full reference. Premium pays for the sheet, not the numbers.