bolt or helicoil pull out strength in G10
bolt or helicoil pull out strength in G10
(OP)
We have specified 240 1 inch long 1/2-13 helicoils in a modified G10.
Every one of the 240 helicoils is to be "proven" by torquing to 75 lb-ft.
Online I found some info that says a thread tapped in G-10 to 1.5 bolt diameters is "stronger" than a "hardened" bolt.
Despite that I am skeptical.
The helicoil folks say they only have pullout strength for metallic materials.
Before I go stirring things up, is there some non-proprietary info to help evaluate this un-built design?
Thanks,
Dan Timberlake
Every one of the 240 helicoils is to be "proven" by torquing to 75 lb-ft.
Online I found some info that says a thread tapped in G-10 to 1.5 bolt diameters is "stronger" than a "hardened" bolt.
Despite that I am skeptical.
The helicoil folks say they only have pullout strength for metallic materials.
Before I go stirring things up, is there some non-proprietary info to help evaluate this un-built design?
Thanks,
Dan Timberlake
RE: bolt or helicoil pull out strength in G10
1/2-13 helicoils. Some axially and some radially. The inserts were 3/4 inch long. The axial insert failed right around about 100 lb-ft. The radial insert did not fail at slightly above 100 lb-ft.
Textron says a 1/2 UNC bolt tightened to ~ 150 lb-ft exerts ~ 17,000 lb tension.
So I say the insert tore out around 11,000 lb tension, which is about a grade 5 bolt.
RE: bolt or helicoil pull out strength in G10
RE: bolt or helicoil pull out strength in G10
RE: bolt or helicoil pull out strength in G10
I personally would not recommend threading anything into G10, unless the the load requirement was neglible. The material is weak inter-layer and can split. This can easily be demonstrated by inserting a stress concentrator (chisel) between layers. If there is significant load suggest to drill through-holes and some sort of clamping mechanism.
RE: bolt or helicoil pull out strength in G10
I'm just sniffing around, looking for trouble, and having those inserts tear out would be BIG trouble. My intuition was along the lines of your "don't so it" comment. So I was trying to quantify the danger. Amazingly I get the feeling I was the first one to do any testing like this. Or maybe just the only one willing to talk about it.
RE: bolt or helicoil pull out strength in G10