Abstract: An improved high-speed spindle assembly for a shank-driven cutting tool comprises a hollow spindle for a collet, a titanium alloy drawbar within the spindle for threadingly engaging the collet, and a tubular resilient member within the spindle surrounding the drawbar for damping vibrations. A transverse resilient member in a threaded portion of the collet resists rotation of the collet on the drawbar. A ten-tooth involute spline provides precise sliding engagement of the drawbar within the spindle. A pair of ball bearings are axially clamped to the spindle by a pair of titanium nuts, a lower nut having a flange closely spaced from an external annular surface of a spindle housing for excluding foreign matter, an upper nut having a cavity for axially retaining a flange of the drawbar.

Abstract: A non-contact type ring setter uses a pressurized gas operated sensor comprising two nozzles, each having an elongated opening for passing the pressurized gas. The openings are spaced apart and opposite to each other. A drill bit is moved relative to a collar, with the line of travel of the drill bit passing through the space between the two openings. Each of the elongated openings has a longitudinal axis substantially parallel to the direction of travel of the drill bit. When the collar and the drill bit are moved relative to each other a predetermined amount, the gas pressure detected by the sensor changes.