GB767512A - Improvements relating to boring bars - Google Patents

Abstract

767,512. Boring-heads. MICKLETHWAIT, E. W. E. (Forbes, S. J., and Schmidt, P. S.). March 2, 1955 [Dec. 3, 1953], No. 33683/53. Class 83 (3). A boring-head 1 comprises an axial flute partly defined by a surface lying in a chordal plane of the head and extending axially in both directions from a cutter 15. The flute clears swarf, and conveys to the cutters coolant delivered to the flute through one or more passages 56 leading from a screwed tube 59 for drawing the shank 8 into a tailstock 2, a key 9 locking the shank. Chordal surfaces 24a, 24b separate the parts of the flute formed by shoulders 27, 29 on the head, which has cutters 14,15 for a roughing cut in the nose of a projectile 3; finishing-cutters 16, 17; an end-facing cutter 18, and a cutter 19 for chamfering the end of the bore; an additional cutter may turn an outer surface. The flute extends into a chordal relief-opening 25 which extends past a shoulder 31 for the tool 18 into a pocket 26. On the opposite side of the head, Fig. 3, the cutting-edges are beneath the cutters, and a flute 23, without chordal relief, is provided. Cutter 19 is secured by grub-screws 52-54 and adjusted by the conical end of screw 54. The other cutters are located by clamping pins 38, 42, 47 (Fig. 2, not shown), contained in a central bore 57, the pins having frusto-conical ends to engage the inclined walls of recesses 39, Fig. 8, in the cutters which are adjustable by screws 37 and clamped in pairs by screws 34. A rib 33 on the cutter 14 slides in a slot 32 in the cutter 15 during adjustment by the screw 37, which engages threads in a block 36 and bears against the cutter 14. The pins 42, 47 are pressed against the cutters by the conical ends of screws 44, 48 and clamped by grub-screws 46, 49 and pin 38 engages threads in the bore 37 and is clamped by grub-screw 41. The Provisional Specification describes also the provision of a coolant opening in both flutes.