UNC Threads

 

The UNC thread is the "American coarse thread" and is used in the USA. It is comparable to the metric standard thread in Europe. In the UNC thread table below you will find technical data as well as tightening torque for UNC threads.

 

 Example:

1/4 inch - 20 x 1/2 inch hex bolt

1/4 = Thread outer diameter 6.35 mm

20 = number of threads to inch (25.4 mm) length

1/2 = length of screw from head 12,70 mm

 

UNC Threads Chart

 

UNC (Coarse Thread) Flank Angle60°

 

Technical Data:

Tightening

Torque in (Nm):

Inch

Gear number

per Inch (Zoll)

Thread Ø

autside in mm

Grade 1

(equivalent to 4.6)

Grade 2

(equivalent to 5.6)

Grade 5

(equivalent to 8.8)

Grade 8

(equivalent to 10.9)

Nr. 00 (UNC 00-90) 90 1,194 mm        
Nr. 1 (UNC 1-64) 64 1,854 mm        
Nr. 2 (UNC 2-56) 56 2,184 mm        
Nr. 3 (UNC 3-48) 48 2,515 mm        
Nr. 4 (UNC 4-40) 40 2,845 mm        
Nr. 5 (UNC 5-40) 40 3,175 mm        
Nr. 6 (UNC 6-32) 32 4,166 mm        
Nr. 8 (UNC 8-32) 32 4,826 mm        
Nr. 10 (UNC 10-24) 24 5,486 mm        
Nr. 12 (UNC 12-24) 24 5,486 mm        
1/64"   0,397 mm        
1/32"   0,794 mm        
1/16"   1,588 mm        
1/8"   3,175 mm        
1/4" 20 6,350 mm 4 7 9 14
5/16" 18 7,938 mm 8 12 20 28
3/8" 16 9,525 mm 14 23 37 52
7/16" 14 11,112 mm 23 37 58 81
1/2" 13 12,700 mm 35 54 88 125
9/16" 12 14,288 mm 50 79 127 180
5/8" 11 15,875 mm 69 110 176 250
11/16" 11 17,462 mm        
3/4" 10 19,050 mm 122 194 313 442
13/16" 10 20,638 mm        
7/8" 9 22,225 mm 197 263 504 712
15/16" 9 23,812 mm        
1" 8 25,400 mm 296 395 755 1067
1 1/8" 7 28,575 mm 419 559 1071 1513
1 1/4" 7 31,750 mm 591  788 1511 2136
1 3/8" 6 34,925 mm 776 1033 1981 2799
1 1/2" 6 38,100 mm 1029 1372 2629 3715
1 9/16"   39,688 mm        
1 5/8" 5 41,275 mm 1275 1699 3257 4601
1 3/4" 5 44,450 mm 1623 2164 4147 5859
2"   50,800 mm 2439 3252 6234 8807
2 1/4"   57,150 mm 3568 4755 9116 12881
2 1/2"   63,500 mm 4880 6507 12471 17623

* All information without guarantee.

Tip !

Here, tools to measure a thread.