544,377. Boring &c. machines. MICROMATIC HONE CORPORATION. Oct. 23, 1940, No. 15592. Convention date, Nov. 27,1939. [Class 83 (iii)] [Also in Group XXIII] In a boring and honing-machine, a revoluble tool having expansible abrading-stones operates on a work-piece attached to a slide which is mounted on a feed-table and is rapidly reciprocated when the feedtable advances the work-piece. Means are provided for stopping the tool and expanding the abrading- elements in pre-determined positions of the worktable. A pair of opposed tools, of which one may be a boring-tool, may be employed for roughing and honing. In the machine shown in Figs. 1 and 5, a honing-tool 58 driven by a motor 29 co-operates with the interior of a work-piece 54 on a slide 53 mounted on a head 51 which is secured to a table 35 supported by guide-rods 34 in a housing 24. The slide is reciprocated in the direction of tool-axis by means of a link 56 connected to the shaft of a motor 57, the pivot of the link being adjustable to vary the stroke. The table is traversed by means of a piston 43, Fig. 12, mounted in a stationary cylinder 44. A head 74 carrying the tool is provided, with a sleeve 75, Fig. 5, which is threaded into a cylinder 62 in connection with a shaft 32 driven by the motor 29. A stationary tube 59 is provided with ball-bearings 61 and a head 64 for supporting the shaft 32 and cylinder 65. The tool is provided with stones 76 co-operating with the tapered end of an adjusting-rod 79 which is operated by a piston 72 mounted in the cylinder 65. The cylinders 44, 62 are arranged in the hydraulic circuit shown in Figs. 12 and 13 and comprising tappet-operated valves 92, 104, a hydraulically-operated valve 95, a starting-valve 102, a speed-regulating valve 86, and a manifold 89 having ports A ... G. A pump 21, Fig. 1, driven by a motor 19, is connected by lines 22, 85, 87,94to the port A and valve 95. When the valves 102, 104 are in the position shown in Fig. 12, liquid flows through line 106, port D, and line 98, the valve 95 is reversed, liquid then flows through line 99, port E, and line 107 to the cylinder 44, and the piston 43 and table 35 are moved towards the left. Since the piston-rod 42 reduces the volume of the left side of the cylinder, the liquid in that side can return through line 108, port F, and line 96, to the pressure lines, and is delivered through the lines 99, 107 to the right side of the cylinder. When the table has moved the work-piece into honing- position, the valve 92 is depressed, and liquid flows through line 122 to move the piston 72 towards the right and merely cause the rod 78 to expand the stones 76. Liquid in the right side of the cylinder 66 can flow through line 123 and valve into the left end of the cylinder. Just before an adjustable stop arrests the table, the valve 104 is thrown over, and liquid flows through line 109, port B, and line 97 to reverse the valve 95. Thereupon, liquid flows through lines 94, 96, port F, and line 108 to the left side of the cylinder, the table is returned, and the liquid in the right side of the cylinder is delivered through line 107, port E, lines 99, 111, 125 to a tank 18. A back-pressure valve 101 regulates the return speed of the table. When the table is completing its return stroke, the valve 92 is permitted to rise, liquid flows through line 122, and the piston 72 is moved to the left, to permit retraction of the stones 76. Liquid in the left side of the cylinder 62 flows through lines 122, 124, port G and line 125 to the tank 18. The tappet 115 for operating the valve 92 is pivoted in a bracket adjustably mounted in a T-slot in the table 35. The tappet can be raised into inoperative position. The valve can be operated manually by a finger-lever. The tappets for operating the valve 104 are mounted in the T-slot. During the time that the work-piece is entirely out of engagement with the tool, an adjustable tappet 129 on a rod 126 on the table opens a switch, the motors 29, 57 are cut out, and rotation of the tool and reciprocation of the work-piece are stopped. Cooling-liquid is supplied to the tool by a pump 139 which pumps the liquid from a reservoir 135 to a filter 133 communicating through a pipe 134 and a passage in the housing with a flexible delivery-pipe. The liquid returns through a space 136 to the reservoir. To provide for rough and finish honing without removing the work-piece 54 from the head 51, a pair of aligned honing-tools, having driving and controlmeans as described above, may be arranged at opposite ends of the head. Means are provided for moving the head to cause the work-piece to cooperate in sequence with honing tools for rough and finish honing. The rough-honing tool may be replaced by a boring-bar.