GB702020A - An improved grinder for drills, taps and like tools - Google Patents

Abstract

702,020. Grinding twist drills, taps, &c. RANEY, W. E. Dec. 28, 1951, No. 30363/51. Class 60 A grinding machine, particularly for twist drills, taps and the like, includes a gauge 33 at one side of the grinding wheel 17, a chuck 48, Fig. 1, to hold the tool and a member supporting the chuck for movement parallel to the wheel axis between positions against the gauge and opposite the wheel and for movement along a predetermined path towards the wheel with the tool contacting the peripheral surface of the latter. A second grinding wheel 16 co-operates with a web-thinning attachment in the form of a vertically adjustable V-block 22, Fig. 2, which is provided with a pin 23 to engage a flute of the drill or tap and thereby rotate the latter as it is displaced axially in the block. Both grinding wheels are mounted on a shaft 7 belt-driven from an electric motor 5 and journalled in a block 6 adjustably clamped to a standard 3 to enable compensation for wheel wear to be effected. The chuck 48 together with a bush 61 to support the tip of the tool is carried by an arm 57 secured to the shaft 68 through an angularly-adjustable connection comprising part-cylindrical members 64, 65 normally held against a stop-member 72 by a spring 73. A handle 71 is provided for manual oscillation of the shaft 68 and the members 64, 65 are relatively adjusted according to the point angle of the drill. The shaft 68 is mounted in anti-friction bearings in a support member 69 which is adjusted relative to a slide member 18 by a screw 75 to provide the required relief angle. The member 18 is slidably mounted in the base 1 of the machine and is arranged to be manually displaced by a lever 27 passing through a slotted pin 31 and connected by a pivotal link 28 to the base of the machine. Movement of the member 18 enables the drill to be positioned against the setting-up gauge 33 which is secured to the block 6 and comprises an inclined edge 38, Fig. 7, with which a lip on the drill is aligned prior to grinding. A lamp L, mirror 34 and magnifying lenses 36, 37 serve to facilitate the alignment which is carried out after the point of the drill has been brought into abutting relationship with a face 39. The latter is parallel to the axis of the wheel 17 and to a second face 40 spaced, say, .008 in. therefrom to set a diamond dressing tool (not shown) which is supported in the bushing 61 for traverse across the peripheral face of the wheel. To position the member 18 for setting a drill relative to the gauge 33 a bolt and lock nut assembly is provided between the member 69 and a lug 81 on the base 1. The jaws of the drill chuck 48 are actuated by relative relation of collars 49 and 50 and the chuck is supported on a bracket 53 between which and the collar 50 a lever 54 and spring washer 55 are interposed enabling the collar 50 to be rotated independently of the lever 54 when adjusting the drill relative to the gauge and in unison with the lever when indexing the drill. For twoflute drills the bracket 53 has a stop pin 56, Fig. 9, and the end of the lever 54 is shaped to provide two positions 180 degrees apart. Indexing of drills with more than two flutes is effected by shaping the lever 54 to rotate through the appropriate angle and by the provision in the bracket 53 of spring detents to engage recesses in the lever 54 which is thereby held in intermediate positions. In a modification, the grinding wheels are directly mounted on the motor shaft and the angularlyadjustable connection between the arm 57 and shaft 68 comprises interengaged arcuate members frictionally retained in adjusted position by a spring finger.