"Pete C." fired this volley in news:519aec82$0$9410
:

McMaster lists 3/8" wide 10' length spring temper stainless (301) coils
in 0.008" and 0.012" thicknesses among others for about $40, 2416K43
and
2416K61. Plenty of other sizes as well.

That's probably the way we'll go, if we cannot properly slit this stuff.
The client traditionally uses bronze, but we can most likely talk them
into SS, so long as it has a suitable fatigue life.

LLoyd