Regarding valve stems for use as tool steel. I have a drawer with
between 200-300 design stamps for use in stamping designs into
sterling silver bracelets,belt buckles,etc,all made from valve stems.
We have been using them for many years.They should be softened,the
design then cut in,then rehardened and tempered. No problems. Ask any
native american silver smith.We also use broken files(we break them)
John Barton