# 5/8 inch bolt torque

Tighten a 5/8-11 UNC grade 5 bolt to 150 ft-lb (203 N·m) with dry threads, or 113 ft-lb when lubricated. Grade 8 takes 212 ft-lb and grade 2 takes 97 ft-lb.

## 5/8 torque by thread series and SAE grade

| Thread | Grade | Dry torque (K 0.20) | Lubricated (K 0.15) | Clamp load |
|---|---|---|---|---|
| 5/8-11 UNC | Grade 2 | 97 ft-lb (132 N·m) | 73 ft-lb | 9,323 lbf |
| 5/8-11 UNC | Grade 5 | 150 ft-lb (203 N·m) | 113 ft-lb | 14,408 lbf |
| 5/8-11 UNC | Grade 8 | 212 ft-lb (287 N·m) | 159 ft-lb | 20,340 lbf |
| 5/8-18 UNF | Grade 2 | 110 ft-lb (149 N·m) | 82 ft-lb | 10,558 lbf |
| 5/8-18 UNF | Grade 5 | 170 ft-lb (230 N·m) | 127 ft-lb | 16,317 lbf |
| 5/8-18 UNF | Grade 8 | 240 ft-lb (325 N·m) | 180 ft-lb | 23,036 lbf |

Clamp load = 75 % of proof load. Method: T = K × F × d.

## 5/8 bolt data

- Threads: 5/8-11 UNC, 5/8-18 UNF
- Wrench: 15/16 in
- Tap drill: 17/32 (0.5313 in) for UNC, 37/64 (0.5781 in) for UNF

## Method

Proof strength from SAE J429 × tensile stress area As = 0.7854 × (D − 0.9743/n)² (ASME B1.1). F = 75 % of proof load. T = K × F × D with K = 0.20 dry, 0.15 lubricated.

## FAQ

**What is the torque for a 5/8 grade 5 bolt?**
About 150 ft-lb dry for 5/8-11 UNC and 170 ft-lb for 5/8-18 UNF, based on 75 % of proof load.

**What is the torque for a 5/8 grade 8 bolt?**
About 212 ft-lb dry for 5/8-11 UNC and 240 ft-lb for 5/8-18 UNF.

**What is the torque for a 5/8 grade 2 bolt?**
About 97 ft-lb dry for 5/8-11 UNC.

**What size wrench fits a 5/8 bolt?**
A standard 5/8" hex cap screw takes a 15/16" wrench or socket.

Source page: https://machinistcharts.com/bolt-torque/5-8-inch/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)