Abstract: A hole cutter having a generally cylindrical body provided with a plurality of first and second cutting teeth around its lower end. Each of the first cutting teeth has a bottom surface defining along its front edge at least two cutting edges which are separated from each other by a shoulder having a certain width and extending substantially circumferentially of the cutter body. Each of the second cutting teeth has a bottom surface provided with a ridgeline extending substantially circumferentially of the body and defining two cutting edges along the front edge of the bottom surface of each second cutting tooth. Each of the cutting edges on each of the second cutting teeth is partly located below one of the cutting edges on each first cutting tooth.

Abstract: A hole cutter having a generally cylindrical cutter body provided around its lower end with a plurality of first cutting teeth each having a plurality of cutting edges, and a plurality of second cutting teeth adapted to scrape a surface cut by the first cutting teeth.

Abstract: A rotating arbor in a sawing machine such as a table saw or radial saw or in a milling machine is provided with a pair of pressing members that are mounted on the arbor so as to be rotated in unison therewith, and a bearing sleeve which is provided on the arbor between the pressing members so as to be rotatable in unison therewith. A rotary blade for forming a groove is clamped from both sides thereof by a pair of clamping members which are mounted on the bearing sleeve in a tilted orientation for holding the rotary blade at an inclined angle with respect to the arbor, the clamping members being pressed between, and hence secured by the pair of pressing members. Turning both clamping members relative to the pressing members allows the clamping members to be tilted together with the rotary blade with respect to the central axis of the arbor.