With chisels you can make holes or recesses for taps and clean or carve taps and difficult to access spots. Here we shall focus on flat carpenter chisels.
Chisels are made of good quality tool steel. The cross section of the blade is usually rectangular, but trapezoidal shapes are quite common as well. At both ends of the wooden handle there are metal hoops to prevent the splitting of the wood. Chisels are available with plastic handles as well; there is no difference between the two as regards usability. There are various sizes, the smallest being 6 mm. The numbering always refers to the width of the blade. For the workpieces described here, a 6 mm chisel is suitable.
(Parts of a chisel: metal hoop (1) handle (2) shoulder preventing the blade from sliding in the handle (3) neck (4) blade (5) bevel (6))
When making a through hole, mark the place of the hole very precisely on both sides. Make the hole to about half its depth from one side, then turn the wood around and finish the hole from the other side. The reason why the hole should be made from two sides is that this way the splintering of the wood fibres on the opposite side can be avoided.
How to make a through recess:
(First cut the fibres)
(Next, cut parallel with the fibres)
(Remove the woodchips from the direction of the grain)
(After turning the wood around, repeat the above steps)
(The material can be removed almost in whole)
(Finally, file or sandpaper the workpiece)
A chisel splits in the direction of the grain and cuts against the grain. When paring in the direction of the grain, work by making light blows so as to avoid splitting the workpiece.
Always lay your workpiece firmly on the table and fix it. Hold the chisel in your left fist with the bevel up towards the piece to be removed and place it somewhat in front of the line drawn. When it is at the right place, strike it with a wooden maul or hammer with medium strength. While the chisel cuts the wood fibres, the bevel pushes the chisel edge to the required size. Put the chisel further on and keep repeating the above until you reach the end of the line drawn.
Always cut the fibres first and remove the wood chips from the grain direction thereafter. Practice on a piece of wood you do not need until you get a feeling for the tool.
How to make an indent:
(Cut the sides of the indent by saw)
(Cut the fibres of the piece to remove with a chisel)
(Remove a piece from grain direction by chisel)
(Turn around the board and repeat the movements with the chisel from the other side)
(The indent you get)
(Use a file to refine the surfaces)
Maintain the bevel of the chisel with great care! A properly sharpened chisel is easy to work with. In many cases you do not need a wooden maul for it at all.