It is essential to get the right level of hardness in the wood. The right level of hardness is not being too hard or too soft. When the material is too tough, it can cause the blades to become dull more quickly when cutting. If the wood is too soft, it will easily be damaged by cutting. Janka's rating for measuring wood hardness has a scale from 100 to 4500. Wood for cutting boards is typically within the 900-1500 range