Kingston Limestone

[Bill Brayman <meta@xxxxxxxxxxx>]

There's no fighting the stone. Hard stone is hard to
chisel. But you will improve your ability fairly quickly
once you start experimenting. You have to take advantage
of fracture mechanics in brittle material. For example
you learn about stress concentration by noticing
existing weak points in the surface structure and making
such weak points. You will find a big difference with
the use of very sharp (tungsten-) carbide tipped
chisels. I've found that often claw chisels work better
than single point chisels. You will find yourself using
a moderate (45 degree) angle mostly because shallow
angles or straight into the stone is not very effective.

You use the flat faced pitching chisel more often than
in soft stone. And use will find that bushing chisels
are often the way to go. Files and rasps are only good
for smoothing. Hard stone is too slow to rasp away. And
finally, your design will beg for more rounded, bulky
form rather than alot of undercuts or other detail. Or
alternately you may find yourself leaving alot of
natural and weathered surfaces as part of the design.
One benefit is that, if it is hard to carve, then it is
probably also rugged. And I, for one, like sculpture
that is impervious to accidental damage.

Regards,
Bill