Wiley Horne
I think you have already spoken to this possibility, but let me ask again anyway....

Could you not isolate this 4” section between a vise on one end and something—maybe another vise—at the other end; 90 degree orientation at one end and 0 degree a t’other. Then get visegrips or other pliers in each hand, and twist the blade beyond its elasticity point, twisting about at about 1-1/4” from each anchored end, so that nearly the full 90 degree twist occurs in this 4” stretch?

Maybe use about a 1/4” to 5/16” blade, considerably thinner than the kerf so it has enough wiggle room to start the turn....

Wiley