To keep the productivity at a maximum it’s important to sharpen the chisels when the chisel tip eventually wears out. It’s not always necessary to harden the chisel every time you sharpen it.
If the chisel tip is slightly worn out you only need to sharpen it. In this case it is not necessary to have a heat treatment.
If the chisel is very worn it may be necessary to reshape it before sharpening.
Heat treatment not carried out in the prescribed manner may result in an excessively brittle chisel tip that can chip or crack. An incorrect heat treatment can also lower chisel hardness, leading to rapid wear or deformation of the chisel tip.