9/16 inch bolt torque specifications (Grade 2, 5, 8)
A 9/16-12 Grade 5 bolt takes 109 ft-lb (147 N·m) and a Grade 8 takes 154 ft-lb (208 N·m). Both values are for plain, dry steel threads (K 0.20) tightened to 75% of proof load.
Contents12 sections
Key takeaways
- The hex cap screw head is 13/16 in but the standard hex nut is 7/8 in 1.
- Oiled threads need 25% less torque for the same clamp load (K 0.15 vs 0.20) 1: 82 ft-lb for Grade 5, 115 ft-lb for Grade 8.
- 9/16-18 fine thread carries 11.5% more clamp load than 9/16-12 (12,940 against 11,600 lbf in Grade 5).
- 9/16 has no structural heavy hex size: RCSC pretension tables go from 1/2 straight to 5/8 in 2.
Quick facts
| Coarse thread | 9/16-12 UNC |
|---|---|
| Fine thread | 9/16-18 UNF |
| Wrench, hex cap screw | 13/16 in |
| Wrench, hex nut | 7/8 in |
9/16 in bolt specifications
| Thread | Pitch | Tensile stress area |
|---|---|---|
| 9/16-12 (UNC) | 12 threads per inch | 0.1820 in² |
| 9/16-18 (UNF) | 18 threads per inch | 0.2030 in² |
| Wrench, hex cap screw | 13/16 in1 | |
Stress areas from ASME B1.1 as tabulated by Fastenal1.
9/16 in torque by grade
| Grade | Plain, dry K 0.201 | Lubricated K 0.151 | Clamp load |
|---|---|---|---|
| Grade 2 | 70 ft-lb95 N·m | 53 ft-lb72 N·m | 7,510 lbf |
| Grade 5 | 109 ft-lb147 N·m | 82 ft-lb111 N·m | 11,600 lbf |
| Grade 8 | 154 ft-lb208 N·m | 115 ft-lb156 N·m | 16,380 lbf |
Calculated with T = K × D × F, where F is 75% of the bolt’s proof load1 and K is the nut factor for each condition. Real preload from a torque wrench scatters by about ±25%3. When the equipment maker gives a torque, use theirs. How these numbers are made.
9/16 in Grade 2 torque
Proof 55,000 psi · yield 57,000 psi · tensile 74,000 psi1. Clamp load at 75% of proof: 7,510 lbf (9/16-12).
| Condition | K | 9/16-12 | 9/16-18 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 70 ft-lb95 N·m | 79 ft-lb106 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 63 ft-lb86 N·m | 71 ft-lb96 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 53 ft-lb72 N·m | 59 ft-lb80 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 56 ft-lb76 N·m | 63 ft-lb85 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 39 ft-lb52 N·m | 43 ft-lb59 N·m |
9/16 in Grade 5 torque
Proof 85,000 psi · yield 92,000 psi · tensile 120,000 psi1. Clamp load at 75% of proof: 11,600 lbf (9/16-12).
| Condition | K | 9/16-12 | 9/16-18 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 109 ft-lb147 N·m | 121 ft-lb164 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 98 ft-lb133 N·m | 109 ft-lb148 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 82 ft-lb111 N·m | 91 ft-lb123 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 87 ft-lb118 N·m | 97 ft-lb132 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 60 ft-lb81 N·m | 67 ft-lb90 N·m |
9/16 in Grade 8 torque
Proof 120,000 psi · yield 130,000 psi · tensile 150,000 psi1. Clamp load at 75% of proof: 16,380 lbf (9/16-12).
| Condition | K | 9/16-12 | 9/16-18 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 154 ft-lb208 N·m | 171 ft-lb232 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 138 ft-lb187 N·m | 154 ft-lb209 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 115 ft-lb156 N·m | 128 ft-lb174 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.164 | 123 ft-lb167 N·m | 137 ft-lb186 N·m |
| Moly pasteMolybdenum disulfide paste | 0.115 | 84 ft-lb115 N·m | 94 ft-lb128 N·m |
An in-between size
9/16 in sits in the hex cap screw dimension table but not in the hex bolt table Fastenal reproduces from ASME B18.2.1 1, and it has no row in the RCSC structural pretension table, which steps from 1/2 to 5/8 in 2. So RCSC gives no 9/16 in pretension to install to; this chart covers 9/16 in SAE cap screws only.
It is also one of two sizes from 1/4 to 1 in where the head and nut take different wrenches: 13/16 in on the cap screw head, 7/8 in on the ASME B18.2.2 hex nut 1. The other is 7/16 in. Put the torque wrench on whichever part you turn.
Coarse or fine thread
The 9/16-12 coarse thread has a tensile stress area of 0.182 in²; the 9/16-18 fine thread has 0.203 in² 1. That is 11.5% more steel, so the fine thread clamps 11.5% harder and needs proportionally more torque: 121 against 109 ft-lb in Grade 5 dry, 171 against 154 ft-lb in Grade 8.
Where 9/16 falls between its neighbours
Clamp load climbs quickly here. A Grade 5 9/16-12 clamps 11,600 lbf, 28% more than a 1/2-13 (9,050 lbf) and about 80% of a 5/8-11 (14,410 lbf). Dry torque goes 75, 109 and 150 ft-lb across those three sizes in Grade 5. If you substitute a 9/16 for a 1/2 in bolt, torque it from this page, not from the 1/2 in chart.
Which grade you have
Plain head means Grade 2, three radial lines Grade 5, six radial lines Grade 8 1. The proof stresses at 9/16 in are 55,000, 85,000 and 120,000 psi 1, so Grade 8 takes 41% more torque than Grade 5 and Grade 5 55% more than Grade 2 (70 ft-lb dry). Use a Grade 5 nut on a Grade 5 bolt and a Grade 8 nut on a Grade 8 bolt 1. See the grades page.
When the chart does not apply
The values size clamp load to the bolt’s proof load and assume the K in each row. They do not check the clamped parts or a tapped hole, and NASA cautions that the default K of 0.20 “should not be used blindly” 3. When the equipment maker gives a torque, use the maker’s value; for lubricants see dry vs lubricated torque.
Sources
- 1
- 2
- 3
- 4
- 5Henkel Corporation (LOCTITE), LOCTITE LB 8012 Moly Paste TDS, April 2015Checked 21 Oct 2026
Spotted a value that doesn’t match its source? Report an error
Related
- 1/2 in1/2-13 Grade 5 bolt torque is 75 ft-lb dry and Grade 8 is 107 ft-lb. Charts for 1/2-13 and 1/2-20 in Grade 2, 5 and 8, dry, zinc-plated and oiled.
- 5/8 in5/8-11 Grade 5 bolt torque is 150 ft-lb dry and Grade 8 is 212 ft-lb. Charts for 5/8-11 and 5/8-18 in Grade 2, 5 and 8, dry, zinc-plated and oiled.
- Grade 5Grade 5 bolt torque from 1/4 in to 1 in, dry, zinc-plated and lubricated, with SAE J429 strength, the three-line head mark and the step down to 74 ksi above 1 in.
- Grade 8Grade 8 bolt torque from 1/4 in to 1 in, dry, zinc-plated and lubricated, with SAE J429 proof, yield and tensile strength and the six-line head marking.
- Grade 2Grade 2 bolt torque from 1/4 in to 1 in, dry, zinc-plated and lubricated, with SAE J429 strength, the drop to 33 ksi proof above 3/4 in, and the plain-head marking.
- Socket size chartSocket sizes for inch hex cap screws, heavy hex structural bolts and metric bolts, including M10, M12, M14 and M22, where ISO and DIN heads differ.
- Bolt torque calculatorBolt torque calculator for SAE and metric bolts by size, thread, grade and lubrication, using T = K × D × F with the proof loads from SAE J429 and ISO 898-1.
- Dry vs lubricated torqueWhy oiled bolts need less torque than dry ones for the same clamp load, with nut factor K values from Fastenal, NASA and Henkel for oil, zinc, anti-seize and moly.