It says in this catalog I found that they are easily sharpened.
These are GREAT dies! They have gotten very expensive. ($30-$60) I
haven't found the correct way to sharpen them and my attempts over the
years aren't that great. When new, they cut like butter, when they are
dull. they rip the steel. They get a lot of use on tool steel and other
tough steels. I have saved all the used inserts for decades in the hope
of sharpening them. Is anyone familiar with sharpening these?