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1/2-20 UNF UNF bolt size
3/4 wrench
wrench size for 1/2-20 UNF UNF bolt
1/2-20 UNF UNF bolt — Automotive, aerospace, structural.
Full specification
| System | Imperial UNF (fine) |
| Nominal diameter | 0.5 in (12.7 mm) |
| Thread pitch | 20 TPI |
| Wrench size | 3/4 |
| Tap drill | 29/64 (11.5 mm) |
| Clearance hole | 17/32 |
| Common grade / class | Grade 5 |
| Typical torque | 110 Nm (81.1 ft·lb) |
🔧 Torque unit converter
Pre-filled with typical torque for 1/2-20 UNF (Grade 5).
About 1/2-20 UNF UNF bolts
Automotive, aerospace, structural.
UNF (Unified National Fine) thread has more threads per inch than UNC (coarse). 1/2-20 UNF has 20 threads per inch.
Fine threads provide better vibration resistance and finer adjustment, commonly used in automotive and aerospace applications.
Frequently asked questions
- What size wrench fits 1/2-20 UNF bolt?
- 1/2-20 UNF bolt uses a 3/4 wrench.
- What is the torque for 1/2-20 UNF bolt?
- Typical torque for 1/2-20 UNF UNF bolt in Grade 5 is about 110 Nm (81.1 ft·lb).
- What is UNF thread?
- UNF (Unified National Fine) thread has more threads per inch than UNC. 1/2-20 UNF has 20 TPI.