The term “Chisel” is believed to have evolved from the Latin word “seco” (I cut) or the French word “ciseau.” As ancient, archaeological discoveries indicate, the crude, stone-fashioned forerunners of today’s chisels, may have been the first of its kind used by primitive man. Although improved, versions are believed to have been used for marble carving in 6th century BC Greece, inscriptions on an ancient tomb of 7th century BC Egypt, suggest otherwise.
Chisels are used primarily for cutting, planing, gouging, carving and finishing of such materials, as wood, stone, metal or marble. However, the end-applications and materials will usually determine which type of chisel is to be used. To perform efficiently, chisels are driven into the base material manually, using different levels of pressure, depending on the nature of the intended task. A hammer or mallet is generally used as the driving force to exert pressure on the hand-held, chisel/s being used.
I do not think there is one workshop that does not have some kind of chisel in it, especially shops that work primarily with wood. In a Luthiers workshop, there will be many different kind of chisels. In violin and guitar making, chisels are most important part of the workshop. But, what makes a chisel good?
Firstly the type of steel that the blade is made of is very important, It must be of a high quality steel, because, it must hold the sharp edge as long as possible. If the steel is too soft, the tool will blunten too quickly. Secondly, the chisel must be sharp at all times. There is nothing worse than working with a blunt chisel.
How do we get this sharp edge?
- Grind the edge to 22,5 degrees – (different chisels can have different angles – 22,5° is the average)
- Remove the burr caused by grinding on a polishing wheel, preferably with a grinding paste.
- Keep the chisel perfectly aligned with the edges when polishing – ie. Do not lift the chisel so the edge goes into the wheel.
- Polish till the beveled edge and the bottom edge is smooth (it will usually start to shine).
If you can shave the hair on your arm with the chisel, then this is usually a good indication that the chisel will be sharp enough to work with. The reason for getting the chisel to a smooth polished surface, is, so that when you push or drive the chisel into the wood, the friction will be reduced making it easier to allow the tool to cut.