I am incorporating small pieces of stainless steel into a design,
and cannot find stainless steel in "jewelry size" stock. The
smallest I've found is 1/8" thick X 1/4" wide strips. I need 1mm
or less thickness, and no more than 3mm width, in various lengths.
I'm not sure what part of the world in which you reside but a source
might be a hobby store, specifically one that caters to model train
fanciers. I have found aluminum, copper, brass and I seem to recall
seeing stainless stock in various gauges and sizes. It may need to
be cut down to the thickness you require but in that guage a light
shear or in the case of the very thin stainless stock an old paper
cutter should work.