Threading: Key Inserts

Threading for outer diameter capability to accept a key insert is available for holes on milled parts and turned. Note that Protolabs does not supply or install the inserts. The diameter for key insert-capable threads are only available for plastics and soft metals such as aluminum, brass, and copper.

 

Threads Minimum modeled diameter (in.) Maximum modeled diameter (in.) 75% hole drill size (in.) Maximum thread depth (in.)
#8-32 0.133 0.137 0.135 0.400
5/16-18 0.271 0.276 0.274 0.650
3/8-16 0.331 0.336 0.334 1.000
7/16-14 0.396 0.401 0.399 1.000
1/2-13 0.452 0.457 0.455 1.000
Note: Any countersinks required by the specification for the insert you plan to use should be in the CAD model. Thread size shown is the external thread of the key insert.
Threads Minimum modeled diameter (in.) Maximum modeled diameter (in.) 75% Hole Drill Size (in.) Maximum thread depth (in.)
#10-32 0.160 0.164 0.162 0.600
#12-28 0.186 0.191 0.189 0.600
1/4-28 0.227 0.231 0.229 0.650
Note: Any countersinks required by the specification for the insert you plan to use should be in the CAD model. Thread size shown is the external thread of the key insert.