The conductor consists of a body 5, two rolling pins 7 located in it, carrying the conductor plate 4, and an average rolling pin-rail 8 with oblique teeth. The rail is fixed in the conductor plate using a key 12. the Rail is connected to a toothed roller 3, which has oblique teeth, the angle of inclination of which is 45 degrees. The roller 3 is located horizontally in the housing 5. A cone is made at one end of the roller, and a conical bushing 1 and a key 12 are mounted on the other. On the threaded end of the M12x1,5-6g, a washer 11 is put on and the nuts 2 are screwed so that a gap of 1 mm is provided between the bushing 1 and the washer 11. Both cones are lapped in the conical holes of the housing 5. Raising and lowering the drill plate is a lever 6, one end of which is screw handle ball 9, and the other screwed into the hub 10, mounted on the end platen 3 and the fixed pin 13. In the upper and lower positions, the rail is stopped as a result of the longitudinal movement of the roller 3 under the influence of the horizontal component of gravity that occurs on the.