A cold chisel should be held “upside down” in your hand, with the thumb closer to the cutting edge. You should not hold the cold chisel so tightly that you end up absorbing the shock yourself once you strike it.
A brick bolster requires holding at a 90 degree angle to the brick you are working on.
Again, holding the chisel too tightly will result in the user absorbing the shock instead.
Other types of chisel may require a different technique.
Using
A chisel is used by holding the cutting edge against the material to be cut and striking the head with a hammer.
When using a cold chisel, gently tapping the head with your hammer allows the tool to make the first cut into the metal.
You may wish to secure the object you want to cut in a vice. This may also allow you to use the vice as a guide for cutting the metal.
An anvil may also be useful when working with certain objects.
When using the chisel it is important that, rather than keeping your eye on the hammer, you keep your eye on the chisel’s cutting edge.