Patent GB-676225-A (GB)
Title: Improvements in or relating to rotary cutting tools
IPC: B23C5/20
Filed: 1949-05-20
Abstract: 676,225. Milling and boring-cutters; reamers. STAPLES, E. M. May 20, 1949 [March 10, 1949], No. 13518/49. Class 83 (iii). A boring, reaming, milling, &c. cutter 5, Fig. 1, comprises a cupped or dished piece of metal with cutting teeth 16 at its periphery and is yieldable to axial pressure to increase its cutting diameter. The cutter 5 is keyed at 11 on a stub shaft 7 projecting from a boring bar 8 and is recesses at 15, Fig. 2, to provide the teeth 16 which are faced with inserts 17 of sintered carbide. A washer 18 of copper may be interposed between the cutter and an adjusting nut 10 in order to facilitate the conduction of heat between the cutter and nut. The axial pressure of the nut 10 on the cutter is resisted by pressure between the perimeter of the bar 8 and the teeth 16. The cutting diameter of the cutter, which may be made from nickel steel alloy, can be adjusted for wear by the nut 10, after which the teeth may be reground to the exact diameter. In a modification, the key 11 may be replaced by projections on the end of the bar 8 which project between the teeth 16 and serve to resist the cutting thrust thereon. In the embodiment illustrated in Fig. 3, the cutter, which can be removed from the shaft 23 without altering its setting, is keyed at 30 to a carrier 27 secured removably by a further key 26 and a nut 24 to the stub shaft 23. The cutter can be adjusted as before by a nut 24 and may have shims 31 to increase its rigidity. In the embodiment illustrated in Fig. 7, the cutter is formed integrally with the bar 40 and with flutes 43 to provide the teeth 44. The bar is counterbored to receive a part 48 which also co-operates with the teeth 44 to increase their effective diameter upon operation of an adjusting screw 49. In the boring bar illustrated in Fig. 9, the cutter 54 is of strip form and is mounted adjustably, by means of a screw 59, in a box 53 which is held releasably, by a leafspring 57 and flanges 52 on the box. in a recess 51 formed in the bar intermediate its ends. The flanges 52 permit a slight amount of float of the box which can be removed to adjust the diameter of the cutter, by deflecting the spring 57. In the embodiment illustrated in Fig. 11, the cutter is locked in adjusted position by bolts 66 which co-operate with slots 65 in the cutter. In a modification, the bolts 66 are replaced by a flanged disc which is threaded on the adjusting nut 62 so as to clamp the teeth 64 between the flange thereon and the end of the bar 61. Fig. 15 illustrates an embodiment in which the teeth 77 of the cutter are formed with flat surfaces 78, 79 so that when the cutter is engaged by a split conical washer 81 operated by an adjusting nut, the teeth engage the end surface of the bar along edges 80. In the shell-reamer illustrated in Fig. 18, the cutter 85 may be secured by screws 86 or brazing to a body 82 which has a driving recess 84 and may have a Morse taper bore 83. The cutting diameter of the cutter is adjusted by nuts 91, 92 engaging a sleeve 89 that may be solid or provided with flutes 90. U.S.A. Specifications 2,093,742 and 2,093,986 are referred to.