Threading: Standard Holes

UNC, UNF, and metric threads are available for standard holes on both milled and turned parts.

UNC threads Minimum modeled diameter (in.) Maximum modeled diameter (in.) 75% hole drill size (in.) Maximum thread depth (in.)*
#2-56  0.067  0.074  0.070 0.200
#3-48 0.076 0.084 0.082 0.200
#4-40 0.085 0.094 0.089 0.300
#5-40 0.098 0.104 0.102 0.300
#6-32 0.105 0.114 0.109 0.400
#8-32 0.130 0.139 0.134 0.400
#10-24 0.145 0.156 0.150 0.600
#12-24 0.171 0.181 0.176 0.600
1/4-20 0.196 0.207 0.201 0.650
5/16-18 0.252 0.265 0.259 0.650
3/8-16 0.307 0.321 0.314 1.000
7/16-14 0.360 0.376 0.372 1.000
1/2-13 0.417 0.434 0.426 1.200
*Obstruction by other features of your part, lead-in treatments, or fixturing requirements may reduce the maximum depth of threads.
UNF threads Minimum modeled diameter (in.) Maximum modeled  diameter (in.) 75% hole drill size (in.) Maximum thread depth (in.)*
#2-64  0.069  0.075  0.072 0.200
#3-56 0.080 0.084 0.083 0.200
#4-48 0.087 0.098 0.093 0.300
#5-44 0.100 0.104 0.104 0.300
#6-40 0.111 0.119 0.115 0.400
#8-36 0.134 0.142 0.138 0.400
#10-32 0.156 0.164 0.160 0.600
#12-28 0.177 0.186 0.182 0.600
1/4-28 0.211 0.220 0.215 0.650
5/16-24 0.267 0.277 0.272 0.650
3/8-24 0.330 0.340 0.335 1.000
7/16-20 0.383 0.395 0.389 1.000
1/2-20 0.446 0.457 0.451 1.200
*Obstruction by other features of your part, lead-in treatments, or fixturing requirements may reduce the maximum depth of threads.
Metric threads Minimum modeled diameter (mm) Maximum modeled diameter (mm) 75% hole drill size (mm) Maximum thread depth (mm)*
M1.6 x 0.35** 1.22 1.32 1.25 3
M2 x 0.4 1.57 1.68 1.60 5.08
M2.5 x 0.45 2.01 2.14 2.05

5.08

M3 x 0.5 2.46 2.60 2.50 7.62
M3.5 x 0.6 2.85 3.01 2.90 10.16
M4 x 0.7 3.24 3.42 3.30 10.16
M5 x 0.8 4.14 4.33 4.20 15.24
M6 x 1.0 4.92 5.15 5.00

16.51

M8 x 1.25 6.65 6.91 6.80 16.51
M10 x 1.5 8.38 8.68 8.50 25.40
M12 x 1.75 10.00 10.44 10.20 30.48
*Obstruction by other features of your part, lead-in treatments, or fixturing requirements may reduce the maximum depth of threads.
**Aluminum Only

NPT Threads

Currently only available for milled parts in aluminum, copper, and brass

Internal NPT Thread Min Modeled Pilot Dia (in.) Max Modeled Pilot Dia (in.) Nominal Modeled Pilot Dia (in.) Min Pilot Depth (in.)
Straight Cylinder
1/16 x 27 0.2343 0.2494 0.2421 0.419
1/8 x 27 0.3268 0.3417 0.3346
1/4 x 18 0.4232 0.4448 0.4331 0.621
3/8 x 18 0.5571 0.5794 0.5669
1/2 x 14 0.6870 0.7165 0.7008 0.795
3/4 x 14 0.8976 0.9257 0.9114
1 x 11-1/2 1.1280 1.1625 1.1437 0.966
1-1/4 x 11-1/2 1.4705 1.5060 1.4882
1-1/2 x 11-1/2 1.7106 1.7450 1.7264
2 x 11-1/2 2.1831 2.2174 2.1988