Tools for very hard stone

["George Graham" <georgergraham@zzzzzzzzzzz>]

Jane,

Here are some thoughts to consider when comparing pneumatic tools to hand
held , and regular steel to carbide tipped chisels. An air hammer does not
hit a chisel harder than a regular hammer, it actually hits lighter and much
faster. A carbide chisel is actually very easy to break if you are using a
hand hammer. Carbide is very brittle and fragile. The thinner and sharper
the edge the more careful you must be. When you are carving a very soft
stone like alabaster , you can work at a very shallow angle to the stone,
but the harder stone forces you to get more perpendicular with the chisel.

When you get into very tough stone, as you are, you will find that a regular
steel point may hold up better to hand hammering then a carbide tipped tool
because the steel is able to absorb the abuse where carbide fractures. If
you take it to the extreme and carve granite, you end up doing almost all
the work with the chisels going straight into the stone, and hitting the
chisel very often and lightly. If you are breaking carbide tools you have to
change your style.

I have worked in some very hard, tough limestone, and had to work the stone
like it was granite.  When I have an area of very rough  tool marks to clean
up I use a 20 grit carborundum wheel on my strongest grinder. Then I go to
sharp hand or air tool to start refining a piece.

Hope this has not put to sleep, and makes a bit of sense to you!
Good carving to you
George Graham