Originally Posted by
Bruce_in_Oz
The advent of exotic alloy steels and induction heating etc, put a whole new face (so to speak0 on things.
"Spot-heating" has been around for a while, too.
If you ever get to fondle a MINT No1 Mk lll, particularly the Lithgow ones, look on the upper Left side of the receiver. There may well be an odd little round "blemish", about 6 to 8mm in diameter and sometimes with a tiny "dot" in the centre of that blemish. This is where the carbon electrode was applied to "spot-heat" the area just behind the left-side locking recess. SOMETIMES, its right-side mate is visible as well. A neat way to heat ONLY the critical area and then quench as appropriate.