If you tap holes in the ring, you will first need to drill them to the right diameter; waterjetting won't leave a consistently round hole. Like any hard metal, the hole will need to be sized for a lower thread engagement. Saab may have some suggestions, I would guess at 50% or less to save the sap from breaking. Taps designed for hardened steel usually have cobalt and vanadium and an oxide over nitride coating. You will also need a heavy duty cutting oil.
Update: How about making a tapped steel spacer and pressing that into a hole in the ring? If you are attaching armour to both sides , then it can't pull out.
Bookmarks