Standard Threads (Internal/External)

Here are the standard thread sizes and constraining geometries recommended by Xometry.

Internal Threads

Thread Hole Diameter(in) Max Thread Depth(in)
UNC/UNF    
0-80 UNC 0.047 0.157
1-64 UNC 0.059 0.177
2-56 UNC 0.070 0.306
2-64 UNF 0.070 0.306
4-40 UNC 0.089 0.394
4-48 UNF 0.094 0.394
5-40 UNC 0.102 0.438
5-44 UNF 0.104 0.438
6-32 UNC 0.107 0.481
6-40 UNF 0.113 0.481
8-32 UNC 0.136 0.525
8-36 UNF 0.136 0.525
10-24 UNC 0.150 0.612
10-32 UNF 0.159 0.612
1/4-20 UNC 0.201 0.750
1/4-28 UNF 0.213 0.750
5/16-18 UNC 0.257 0.844
5/16-24 UNF 0.272 0.844
3/8-16 UNC 0.313 0.938
3/8-24 UNF 0.332 0.938
7/16-14 UNC 0.368 1.078
7/16-20 UNF 0.391 1.078
1/2-13 UNC 0.422 1.242
1/2-20 UNF 0.453 1.242
9/16-12 UNC 0.484 1.250
9/16-18 UNF 0.500 1.250
5/8-11 UNC 0.531 1.250
5/8-18 UNF 0.563 1.250
3/4-10 UNC 0.656 1.250
3/4-16 UNF 0.688 1.250
Metric    
M2x0.4 0.063 0.306
M2.5×0.45 0.081 0.350
M3x0.5 0.098 0.438
M3.5×0.6 0.114 0.481
M4x0.7 0.130 0.525
M5x0.8 0.165 0.612
M6x1.0 0.197 0.750
M8x1.25 0.264 0.900
M10x1.5 0.335 0.938
M12x1.75 0.402 1.242
STI Threads    
2-56 UNC 0.091 0.306
4-40 UNC 0.118 0.394
4-48 UNF 0.118 0.394
5-40 UNC 0.134 0.438
6-32 UNC 0.146 0.481
8-32 UNC 0.172 0.525
8-36 UNF 0.172 0.525
10-24 UNC 0.201 0.612
10-32 UNF 0.201 0.612
1/4-20 UNC 0.264 0.750
M2x0.4 0.083 0.306
M2.5×0.45 0.104 0.350
M3x0.5 0.126 0.438
M4x0.7 0.167 0.525
M5x0.8 0.209 0.612
M6x1.0 0.248 0.750
M8x1.25 0.331 0.900
M10x1.5 0.413 0.938
M12x1.75 0.492 1.242

External Threads

Thread Boss Diameter (in) Max Thread Length (in)
UNC/UNF    
2-56 UNC 0.086 0.20
2-64 UNF 0.086 0.20
4-40 UNC 0.112 0.22
4-48 UNF 0.112 0.22
5-40 UNC 0.125 0.25
5-44 UNF 0.125 0.25
6-32 UNC 0.138 0.28
6-40 UNF 0.138 0.28
8-32 UNC 0.164 0.33
8-36 UNF 0.164 0.33
10-24 UNC 0.190 0.38
10-32 UNF 0.190 0.38
1/4-20 UNC 0.250 0.50
1/4-28 UNF 0.250 0.50
5/16-18 UNC 0.313 0.675
5/16-24 UNF 0.313 0.675
3/8-16 UNC 0.375 0.75
3/8-24 UNF 0.375 0.75
7/16-14 UNC 0.438 0.875
7/16-20 UNF 0.438 0.875
1/2-13 UNC 0.500 1.00
1/2-20 UNF 0.500 1.00
9/16-12 UNC 0.563 1.25
9/16-18 UNF 0.563 1.25
5/8-11 UNC 0.625 1.25
5/8-18 UNF 0.625 1.25
3/4-10 UNC 0.750 1.50
3/4-16 UNF 0.750 1.50
7/8-9 UNC 0.875 2.00
7/8-14 UNF 0.875 2.00
1″-8 UNC 1.000 2.50
1″-12 UNF 1.000 2.50
Metric    
M2x0.4 0.079 0.276
M2.5×0.45 0.098 0.276
M3x0.5 0.118 0.276
M3.5×0.6 0.138 0.276
M4x0.7 0.157 0.500
M5x0.8 0.197 0.500
M6x1.0 0.236 0.500
M8x1.25 0.315 0.500
M10x1.5 0.394 1.000
M12x1.75 0.472 1.000
M14x2.0 0.551 1.500
M16x2.5 0.630 1.500
M24x3.0 0.945 2.000
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