We did some testing of our own for threads in aluminium - M5 up to M12 - every time the cap head screw sheared before the thread stripped.
We use helicoils in aluminium for parts in our machines that changed a lot, for every size change of product, simply to avoid wear and tear. If they wear, it's reasonably simple to change the insert.
We use helicoils in aluminium for parts in our machines that changed a lot, for every size change of product, simply to avoid wear and tear. If they wear, it's reasonably simple to change the insert.