Abstract
Drilling thrust force changes with the change of hand-feed rate. An attempt for discrimination and classification of the drilling thrust force based on the features extruded from that was carried out. Mahalanobis' D^2 from the reference was calculated on each examination. Thrust force figures attended with the drilling mode were evidently classified by the Mahalanobis' D^2. This result suggests the applicability of this method to the evaluation of the skill at hand-feed drilling.
