"Leo Lichtman" wrote in message
...

"Robert Swinney" wrote: Lloyd, please elaborate a little on "forging" and
"hardy-hole". You are talking about heating the head beyond red and
hammering it into a hole (die) of the desired shape - no?
^^^^^^^^^^^^^^^^
The idea is correct, but the words aren't. A "hardy hole" is a square
hole in the top of an anvil that can be used to hold things like dies or
chisel edges. You would need a properly shaped die to pound the red hot
steel into. The trick will be making a die with the proper internal
contour to produce the shape you need.

But Leo, you need to start with a hardy hole to accommodate the square shank
on the carriage bolt. Then you grind/file/drill/chisel the top of the hole
to the profile you wish for the head. This particular design is almost
trivial. Start with a square hole and countersink it to the head profile -
or start with a countersunk round hole, and square up the hole.

LLoyd