GB598240A - Improvements in or relating to holders for boring tools - Google Patents

Abstract

598,240. Boring - heads. BOWDLER, J. A., and BELLAMY, E. W. Nov. 17, 1944, No. 22804. [Class 83 (iii)] Boring-heads have the cutter carrying member rotatable, for adjustment of diameter of cut, about an axis eccentric to that of the hole. The shank 1, Fig. 1, has a slightly eccentric spigot 2 that carries a sleeve 3 having roughing and finishing cutters 4 secured by screws. An enlargement 5 of the sleeve mounts a worm engaging a worm-wheel 7 on the spigot and is slotted at 10, Fig. 7, for clamping by a screw 11 after adjustment. The thrust flange on the worm spindle has a segment removed to clear the worm-wheel during assembly. Graduations on the flange 12 assist in adjusting the cutter, but preferably do not directly give cut diameter. If, however, a direct reading scale be adopted separate zero marks are required for different materials, and these may be provided on interchangeable rings. In a modification for boring small holes, the sleeve is shortened, increased in diameter and provided with an inclined slot to receive the shank 4a, Fig. 6, of a single point boring-tool. Axial adjustment of the cutter in the slot provides a rough diameter setting prior to clamping at 14. The spigot is recessed at 2a to clear the end of the tool. In another form, the worm 6, Fig. 7, has a thrust collar 15 screwed on the spindle and locked by a screw 16 of finer pitch or opposite hand. In another form, the spigot is tapered and the flange 12 carries an annular projection seating in a groove in the enlargement 5. In a further form, the spigot has a conical seating located between the flange 12 and the worm-wheel. The worm-teeth may extend round part only of the spigot as shown in Fig. 7 to prevent use of that part of the eccentric throw that would cause dig-in, in the event of slipping during cutting.