Suggested Assembly Torque Values to Produce Corresponding Bolt Loads
| Size | Tensile Stress Area AS Square Inch |
SA193 & ASTM 193 B7 Studs with A194 2H Heavy Hex Nuts |
||
|---|---|---|---|---|
| Clamp Load P. Lbs. |
Tightening Torque | |||
| Dry | Lubed | |||
| K= .223 Ft. Lbs. |
K= .167 Ft. Lbs. |
|||
| 1/2 – 13 | 0.138 | 10,350 | 96 | 72 |
| 9/16 – 12 | 0.177 | 13,275 | 139 | 104 |
| 5/8 – 11 | 0.220 | 16,500 | 192 | 143 |
| 3/4 – 10 | 0.327 | 24,525 | 342 | 256 |
| 7/8 – 9 | 0.452 | 33,900 | 551 | 413 |
| 1 – 8 | 0.594 | 44,550 | 828 | 620 |
| 1-1/8 – 8 | 0.776 | 58,200 | 1217 | 911 |
| 1-1/4 – 8 | 0.984 | 73,800 | 1714 | 1284 |
| 1-3/8 – 8 | 1.215 | 91,125 | 2328 | 1744 |
| 1-1/2 – 8 | 1.471 | 110,325 | 3076 | 2303 |
| 1-5/8 – 8 | 1.769 | 132,675 | 4006 | 3000 |
| 1-3/4 – 8 | 2.06 | 154,500 | 5024 | 3763 |
| 1-7/8 – 8 | 2.41 | 180,750 | 6298 | 4716 |
| 2 – 8 | 2.74 | 205,500 | 7638 | 5720 |
| 2-1/4 – 8 | 3.52 | 264,000 | 11,038 | 8266 |
| 2-1/2 – 8 | 4.40 | 330,000 | 15,331 | 11,481 |
| Size | SA193 & ASTM 193 B7M Studs with A194 2HM Heavy Hex Nuts |
||
|---|---|---|---|
| Clamp Load P. Lbs. |
Tightening Torque | ||
| Dry | Lubed | ||
| K= .223 Ft. Lbs. |
K= .167 Ft. Lbs. |
||
| 1/2 – 13 | 7,866 | 73 | 55 |
| 9/16 – 12 | 10,089 | 105 | 79 |
| 5/8 – 11 | 12,540 | 146 | 109 |
| 3/4 – 10 | 18,639 | 260 | 194 |
| 7/8 – 9 | 25,764 | 419 | 314 |
| 1 – 8 | 33,858 | 629 | 471 |
| 1-1/8 – 8 | 44,232 | 925 | 692 |
| 1-1/4 – 8 | 56,088 | 1303 | 976 |
| 1-3/8 – 8 | 69,255 | 1770 | 1325 |
| 1-1/2 – 8 | 83,847 | 2337 | 1750 |
| 1-5/8 – 8 | 100,833 | 3045 | 2280 |
| 1-3/4 – 8 | 177,420 | 3818 | 2860 |
| 1-7/8 – 8 | 137,370 | 4786 | 3584 |
| 2 – 8 | 156,180 | 5805 | 4347 |
| 2-1/4 – 8 | 200,640 | 8389 | 6282 |
| 2-1/2 – 8 | 250,800 | 11,652 | 8726 |
| Size | Tensile Stress Area AS Square Inch |
SA320 & ASTM A320 L7 Studs with A194 Grade 7L Heavy Hex Nuts |
||
|---|---|---|---|---|
| Clamp Load P. Lbs. |
Tightening Torque | |||
| Dry | Lubed | |||
| K= .223 Ft. Lbs. |
K= .167 Ft. Lbs. |
|||
| 1/2 – 13 | 0.138 | 10,350 | 96 | 72 |
| 9/16 – 12 | 0.177 | 13,275 | 139 | 104 |
| 5/8 – 11 | 0.220 | 16,500 | 192 | 143 |
| 3/4 – 10 | 0.327 | 24,525 | 342 | 256 |
| 7/8 – 9 | 0.452 | 33,900 | 551 | 413 |
| 1 – 8 | 0.594 | 44,550 | 828 | 620 |
| 1-1/8 – 8 | 0.776 | 58,200 | 1217 | 911 |
| 1-1/4 – 8 | 0.984 | 73,800 | 1714 | 1284 |
| 1-3/8 – 8 | 1.215 | 91,125 | 2328 | 1744 |
| 1-1/2 – 8 | 1.471 | 110,325 | 3076 | 2303 |
| 1-5/8 – 8 | 1.769 | 132,675 | 4006 | 3000 |
| 1-3/4 – 8 | 2.06 | 154,500 | 5024 | 3763 |
| 1-7/8 – 8 | 2.41 | 180,750 | 6298 | 4716 |
| 2 – 8 | 2.74 | 205,500 | 7638 | 5720 |
| 2-1/4 – 8 | 3.52 | 264,000 | 11,038 | 8266 |
| 2-1/2 – 8 | 4.40 | 330,000 | 15,331 | 11,481 |
| Size | SA320 & ASTM A320 L7M Studs with A194 7ML Heavy Hex Nuts |
||
|---|---|---|---|
| Clamp Load P. Lbs. |
Tightening Torque | ||
| Dry | Lubed | ||
| K= .223 Ft. Lbs. |
K= .167 Ft. Lbs. |
||
| 1/2 – 13 | 7,866 | 73 | 55 |
| 9/16 – 12 | 10,089 | 105 | 79 |
| 5/8 – 11 | 12,540 | 146 | 109 |
| 3/4 – 10 | 18,639 | 260 | 194 |
| 7/8 – 9 | 25,764 | 419 | 314 |
| 1 – 8 | 33,858 | 629 | 471 |
| 1-1/8 – 8 | 44,232 | 925 | 692 |
| 1-1/4 – 8 | 56,088 | 1303 | 976 |
| 1-3/8 – 8 | 69,255 | 1770 | 1325 |
| 1-1/2 – 8 | 83,847 | 2337 | 1750 |
| 1-5/8 – 8 | 100,833 | 3045 | 2280 |
| 1-3/4 – 8 | 177,420 | 3818 | 2860 |
| 1-7/8 – 8 | 137,370 | 4786 | 3584 |
| 2 – 8 | 156,180 | 5805 | 4347 |
| 2-1/4 – 8 | 200,640 | 8389 | 6282 |
| 2-1/2 – 8 | 250,800 | 11,652 | 8726 |
NOTES:
1. Tightening torque values from the formula T=KDP, where T = tightening torque,
lb. ft. K – torque friction coefficient, D = nominal bolt diameter, in.; and P = bolt
clamping load developed by tightening, lb.
2. Clamp load is also known as preload or initial load in tension on bolt. Clamp load
(lb.) is calculated by arbitrarily assuming useable bolt strength is 75% of bolt
proof load (PSI) times the stress area (sq. in.) of threaded section of each bolt
size. Higher or lower values of clamp load can be used depending on the
application requirements and the judgement of the designer.
3. No proof load has been established by ASTM. Value shown in table are assumed
at 95% of yield strength.
