Wednesday, March 13, 2024

What Are These Called?

I cannot tap carbon fiber but I can use a stainless steel insert epoxied into a hole that has a 6-32 thread inside.  This gives me grip and ability to disassemble.  For walls these would be the little plastic inserts that go in the wall.

At McMaster-Carr: 18-8 Stainless Steel Twist-Resistant Hex-Shaped Inserts
for Plastics, 6-32 Thread Size

Unfortunately I am having trouble finding them .1875" long.  They seem to start at 0.25" OAL.  I cut buy the 0.25" length and mill them to length.  Carbide mill would quickly cut them to length.  It just seems like a lot of work if I could find shorter.  

These will not be holding any real load.  They mostly position parts in the only directions where there is no appreciable tension or shear.

UPDATE: McMaster-Carr has Stainless Steel Helicoils that are .138" long.  While these are designed to be turned into tapped holes, I will just epoxy them into holes in the carbon fiber composite.  This is definitely not what these are intended to do.


  1. Is there a question here or didn't you already answer it?

  2. (threaded inserts for plastics)