I've recently gotten a question forwarded to me by a friend on a mailing list. The original question was:
Some of my Greenlees are probably 20+ years old now and the cutting
> sections have become dulled. These are expensive boogers to just
> toss out and replace, so how can they be resharpened?
to which I replied:
Well ... *I* would try grinding back the points and edges on the
> punch -- on the inside, not touching the outside. I suspect the points
> to have experienced the worst dulling I would probably use a die grinder
> for the purpose -- either one powered by compressed air, or an electric
> one, with the punch held in a vise, or bolted down to the workbench by a
> screw into the dive screw hole.
> If the edges in the die are also rounded, you've got less meat
> to grind back there -- but I would do *that* on a surface grinder to
> make sure that it is evenly reduced all the way around.
> Note -- as you grind back ether, you will be increasing the gap
> between punch and die -- and thus possible burr from the punching
> operation. This is because both punch and die are slightly tapered, to
> keep them from binding in the workpiece.
> If you want, I can post the question on rec.crafts.metalworking,
> and try to gather it all together for you. Be warned that things are
> likely to drift off topic.
And his latest return is:
I think that what he's really interested in is knowing what kind of
> shop he might take it to to get it sharpened. He's an electronics
> tech, not a machinist. Remember R & M Saw and Tool around the Navy
> Yard? They would probably know what to do with it, but I don't know if
> there are shops like that any more. He's in Oklahoma City.
> Toss it out to the Metalworking newsgroup and see what happens.
> Suggest that someone might know of a sharpening service that's smart
> enough (with your excellent analysis) to know which end to blow into.
So -- any suggestions (including corrections to what I suggested)? I'll try to bundle up everything which comes back reasonably on topic and pass it on. In particular, suggestions of who could do the task in the Oklahoma City area would be welcome.