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.
Size	Stress 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 UNC	0.0318	1313	5.5	2029	8.5	2864	12
5/16-18 UNC	0.0524	2163	11	3342	17	4719	25
3/8-16 UNC	0.0775	3196	20	4940	31	6974	44
1/2-13 UNC	0.1419	5853	49	9046	75	12771	106
5/8-11 UNC	0.226	9323	97	14408	150	20340	212
3/4-10 UNC	0.3345	13797	172	21322	267	30101	376
UNF - Unified fine
1/2-20 UNF	0.16	6598	55	10197	85	14396	120
3/4-16 UNF	0.373	15385	192	23776	297	33566	420

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.

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