The three basic styles of chisels are straight, skew, and bull nose.
Chisels have straight cutting edge profiles and are used primarily to round over and shape an area of your carving. The straight chisel’s edge is at 90 degrees to the tool shaft; if the cutting edge is at 45 degrees it is called a skew chisel. The straight line of the cutting edge removes small flat planes of wood from the carving. A bull nose chisel, shown in the photo to the right, has a flat profile but the side edges are slightly rounded. This keeps the chisel edges from creating small cut lines during the stroke.
Placing the chisel with the flat side – back side – of the cutting edge against the wood leads the tool into a deep cut. Flip it over, with the angled top side of the tool against the wood, and you can create a very thin shaving cut.