Effect of removal of deep valleys on the evaluation of machined surfaces of wood

The purpose of this paper is to propose a new method for the effective evaluation of the surface roughness of a sanded hardwood regardless of its cellular structure. The surfaces of samples of Japanese oak (Quercus mongolica var. grosseserrata) and Japanese beech (Fagus crenata) were sanded using various grades of coated abrasives and the parameters of surface roughness were estimated using both the proposed and conventional methods. For Japanese oak, the estimates of roughness parameters obtained using the proposed method were correlated with grit number, while for Japanese beech, the estimates obtained using both methods were correlated with grit number. This result suggests that the proposed method is useful for evaluating the surface roughness of hardwood samples, particularly when the vessels are of large diameter.