Threading: Coil Inserts

Coil insert threading is available for UNC, UNF, and metric threads on both milled and turned parts. Note that Protolabs does not supply or install the inserts. The diameter for insert-capable threads are only available on plastics and soft metals such as aluminum, brass, and copper.

chevron_left
chevron_right
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.