GB294423A - Boring tools - Google Patents

Abstract

294,423. Schmidgall, C. H. Dec. 12, 1927. Drills and cutters. - A tool for boring square holes by means of side cutters comprises a body 2 through which passes a driving shaft 6 having a bevel pinion 5 on its end in engagement with two large bevel wheels 15. Each of the latter is formed integral with or attached to a cutter 16 and .also engages three other pinions 5, two of which carry small cutters 13 while the third'carries a bit 11 for boring a preliminary hole in wood. When operating on metal the bit 11 is replaced by a guiding-plug which fits a previously-formed hole in the work. The body is provided with openings 4 extending completely through the body to receive the pinions 5. The pinions 5, which are all of the same size, are each provided with ten teeth and the gears 15 have each twenty teeth, while the cutters 16, 13 have twenty and five cutting teeth each respectively, so that the teeth of the cutters 13 may overlap the teeth of the cutters 16 and produce flat sides on the work. The spindles 8 which carry the pinions 5 have bearings 12, 14 in the body 2 at opposite sides of the pinions and the bit 11 rests against a shoulder 10 on its spindle. The cutters 16 are mounted on the body by central screws 19 and are provided with annular recesses 20 which receive annular bosses 3 on the body to exclude cuttings from the gearing. The size of aperture produced by the tool may be varied by substituting cutters 16 of different diameter and thickness and cutters 13 of different thickness, while the section of the aperture may be varied by providing cutters of different shape.