Larry Jaques wrote:
...
Bob, how about something in the way of a wedge? Dual jaws with a
little tongue which pushes them apart?

Maybe. But we're using bars sharpened to almost knife edge to get in
without distorting the tin too much. Two jaws might make it too thick.
I'll think about it.

I'll bet that if you can come
up with something like that, you could sell them to metal shops.
You'll be rich!

I'll leave that to you - ambition did not follow me into retirement,
thank goodness.

Bob