GB602830A - Improvements in or relating to adjustable reamers and boring tools - Google Patents

Abstract

602,830. Boring-heads; reamers. ENGLISH STEEL CORPORATION, Ltd., and ARCHER, J. Oct. 17, 1945, No. 27280. [Class 83 (iii)] An adjustable reamer or boring-tool has a pair of opposed cutters positively connected by a rotatable adjusting device engaging the cutters by threads of different pitch but of the same hand. The cutter head has two jaws 63 and the cutters 66, of square or other non-circular section, project beyond the jaws through holes 65. Between the jaws is an adjusting device comprising a differential screw with a central flange 73 of the same size and section as the cutters (to facilitate assembly) and two threaded portions 71, 72, of different pitch but of the same hand, engaging tapped holes 74 in the cutters. The flange 73 is a sliding fit in a hole 76 in an adjusting ring 77, to allow float of the cutters and flanges 78 on the adjusting ring prevent end play of the ring in the jaw. The circumference of the ring is serrated and bears a scale co-operating with an index mark on an apertured cover 85. A leaf spring 90 attached to the cover has one prong 91. locking the ring in position by engaging the serrations and two other prongs 92 engage notches 95 in the cutters to hold them approximately central. To give a wider range of adjustment, the cutters can be removed from the holder and one rotated with respect to the other. For use as a boring tool, only one cutter is used, the other member being a dummy bearing on the opposite side of the bore and both may be locked against floating by screws 118. In a modification, the adjusting ring has no flanges 78 and is integral with the threaded portions 71, 72, the cutters each fit in a square hole formed in each jaw by slotting it and fitting a cover-plate, and the leaf spring is fitted at the bottom of the jaw and has two prongs engaging the serrated adjusting ring. Specification 602,860 is referred to.