Threading: Coil Inserts

Coil insert threading is available for UNC, UNF, and metric threads 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 0.090 0.096 0.091 0.300
#3-48 0.105 0.110 0.107 0.400
#4-40 0.117 0.125 0.119 0.400
#5-40 0.131 0.137 0.132 0.400
#6-32 0.145 0.153 0.147 0.600
#8-32 0.171 0.178 0.173 0.600
#10-24 0.199 0.208 0.201 0.650
#12-24 0.225 0.234 0.227 0.650
1/4-20 0.261 0.270 0.266 0.650
5/16-18 0.324 0.334 0.332 1.000
3/8-16 0.389 0.399 0.397 1.200
7/16-14 0.453 0.464 0.453 1.200
1/2-13 0.515 0.531 0.531 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 0.090 0.095 0.092 0.300
#3-56 0.103 0.104 0.104 0.300
#4-48 0.117 0.123 0.120 0.400
#6-40 0.144 0.150 0.148 0.600
#8-36 0.170 0.177 0.174 0.600
#10-32 0.197 0.204 0.200 0.650
1/4-28 0.258 0.265 0.261 0.650
5/16-24 0.322 0.329 0.325 1.000
3/8-24 0.384 0.391 0.387 1.000
7/16-20 0.448 0.456 0.452 1.200
1/2-20 0.511 0.519 0.515 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)*
M2 x 0.4 2.09 2.14 2.14 5.08
M2.5 x 0.45 2.55 2.65 2.60 7.62
M3 x 0.5 3.11 3.25 3.18 10.16
M3.5 x 0.6 3.68 3.79 3.70 15.24
M4 x 0.7 4.15 4.33 4.24 15.24
M5 x 0.8 5.17 5.37 5.27 16.51
M6 x 1.0 6.22 6.41 6.31 16.51
M8 x 1.25 8.27 8.48 8.38 25.40
M10 x 1.5 10.33 10.56 10.56 30.48
M12 x 1.75 12.38 12.64 12.51 30.48
*Obstruction by other features of your part, lead-in treatments, or fixturing requirements may reduce the maximum depth of threads.