Inch Torque Guide — Grades 2, 5, 8
Starting-point tightening torques for coarse-thread inch hex bolts, calculated from SAE J429 proof loads. Use them only when the manufacturer or engineer has not given a torque.
Estimated torque, lb-ft (K = 0.20, clamp load = 75% of proof)
| Size-TPI | Grade 2 | Grade 5 | Grade 8 |
|---|---|---|---|
| 1/4-20 | 5 | 8 | 12 |
| 5/16-18 | 11 | 17 | 25 |
| 3/8-16 | 20 | 31 | 44 |
| 7/16-14 | 32 | 49 | 70 |
| 1/2-13 | 49 | 75 | 105 |
| 9/16-12 | 70 | 110 | 155 |
| 5/8-11 | 97 | 150 | 210 |
| 3/4-10 | 170 | 265 | 375 |
| 7/8-9 | 165 | 430 | 605 |
| 1-8 | 250 | 645 | 910 |
| 1-1/8-7 | 355 | 795 | 1,290 |
| 1-1/4-7 | 500 | 1,120 | 1,815 |
| 1-3/8-6 | 655 | 1,470 | 2,380 |
| 1-1/2-6 | 870 | 1,950 | 3,160 |
Method: T = K x D x F, with F = 0.75 x proof load. K = 0.20 represents plain or zinc-plated steel, dry. For lubricated threads (K about 0.15) multiply by 0.75. Values rounded.
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
Estimated assembly torque · UNC coarse thread · SAE J429 grades
What it is
FIELD IDENTIFICATION
Starting-point tightening torques for coarse-thread inch hex bolts, calculated from SAE J429 proof
loads. Use them only when the manufacturer or engineer has not given a torque.
MFG
Gr 2 / 5 / 8
Torque values are for stated conditions only
Estimated torque, lb-ft (K = 0.20, clamp load = 75% of proof)
Size-TPI
Grade 2
Grade 5
Grade 8
1/4-20
5
8
12
5/16-18
11
17
25
3/8-16
20
31
44
7/16-14
32
49
70
1/2-13
49
75
105
9/16-12
70
110
155
5/8-11
97
150
210
3/4-10
170
265
375
7/8-9
165
430
605
1-8
250
645
910
1-1/8-7
355
795
1,290
1-1/4-7
500
1,120
1,815
1-3/8-6
655
1,470
2,380
1-1/2-6
870
1,950
3,160
Method: T = K x D x F, with F = 0.75 x proof load. K = 0.20 represents plain or zinc-plated steel, dry. For lubricated threads (K about 0.15) multiply by 0.75. Values rounded.
Key points
Not for structural bolts (A325/A490): those are pretensioned by RCSC methods, not a torque chart.
The K factor changes with finish, lubrication and threadlocker. A different K means a different torque.
Governing standards: SAE J429 (2014) (proof stress); ASME B1.1-2023 (stress area). Editions shown are the latest confirmed as of September 2026. The drawing and the governing
standard always take precedence over this sheet.
torquing any fastener. Verify the current governing standard, project documents, OEM requirements, size, thread, coating and lot certification. To the fullest extent permitted by law, The Fastener App disclaims liability
arising from reliance on this reference.
Fastener Guide reference FG-208362 · thefastenerapp.com/fastener-guide/technical-reference/inch-torque-guide-grades-2-5-8 · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
