Mark _australia said..
Swindy, no stainless in the larger sizes. I went through all their stuff online .....

segler I reckon you have been a bit lucky as the reason all the major brands went to PT / thread forming screw long ago is the Chinook self tappers ripped out often when jumping. I have used the same ones as you, but only had success with double screws each end and in brand-new Chinook inserts )which have a hole about 0.25mm smaller than the more common / standard inserts used by everyone else).

The annoying thing is the screw seems to be specially ordered by Cobra and Unifiber and then they sell individually at an obscene markup

albers said..
You could try plumbers tape