Basic stone carving tools fall into four categories:
Percussion tools for hitting – such as mallets, axes, adzes, bouchards and toothed hammers.
Tools for rough shaping of stone, to form a block the size needed for the carving. These include feathers and wedges and pitching tools.
Chisels for cutting – such as lettering chisels, points, pitching tools, and claw chisels. Chisels in turn may by hand held and hammered or pneumatic powered.
Abrasives for erosion – such as carborundum blocks, drills, saws, grinding and cutting wheels, water erosion machinery and dressing tools such as French and English drags.
More advanced processes, such as laser cutting and jet torches, use sudden, high temperature to shatter the stone.
The use of chisels for stone carving is possible in several ways. Two are:
The masons stroke, in which a flat chisel is used at approximately 90 degrees to the surface in an organized sweep. It shatters the stone beneath it and each successive pass lowers the surface.
The lettering stroke, in which the chisel is used along the surface at approximately 30 degrees to cut beneath the existing surface.
There are many types and styles of stone carving tools, each carver will decide for themselves which tools to use. Traditionalists might use hand tools only.
Lettering chisels for incising small strokes create the details of letters in larger applications.
Fishtail carving chisels are used to create pockets, valleys and for intricate carving, whilst providing good visibility around the stone.
Masonry chisels are used for the general shaping of stones.
Stone point tools are used to rough out the surface of the stone.
Stone claw tools are used to remove the peaks and troughs left from the previously used tools.
Stone pitching tools are used to remove large quantities of stone.
Stone nickers are used to split stones by tracing a line along the stone with progressive strikes until the stone breaks along the line.
Powered pneumatic hammers make the hard work easier. Progress on shaping stone is faster with pneumatic carving tools. Air hammers (such as Cuturi) place many thousands of impacts per minute upon the end of the tool, which would usually be manufactured or modified to suit the tool. This type of tool creates the ability to ‘shave’ the stone, providing a smooth and consistent stroke, allowing for larger surfaces to be worked.
Among modern tool types, there are two main stone carving chisels:
Heat treated high carbon steel tools – Generally forged
Tungsten carbide tipped tools – Generally forged, slotted, and carbide inserts brazed in to provide a harder and longer-wearing cutting edge.