Abstract: An air-bearing supported, freely rotated spinning or twisting ring carrying a yarn traveler having radical and cylindrical air-bearings and an annular plenum cavity in at least one of the cylindrical air-bearing surfaces for generally open, unencumbered and continuous admission of pressurized air to the air-bearings. The air-bearings communicate through an annularly disposed mutually connecting enlarged air space. Time delay means is provided for reducing the air supply to the air-bearings at a selected predetermined time after de-energizing the power drive of the apparatus.

Abstract: A tool holder is provided for the cross slide of a lathe. A cutoff tool extends horizontally from the holder toward the rotational axis of a workpiece in the lathe, and a chamfering tool extends vertically downwardly from the holder in a common cutting plane with the cutoff tool. As the cutoff tool is advanced radially into the workpiece to cut a portion off the end thereof, the chamfering tool is thereby moved chordally with respect to the peripheral edges of the annular groove being formed in the workpiece by the cutoff tool. The cutting edges of the chamfering tool are preferably spaced from the cutoff tool such that they engage the groove edges during the cutting of the groove and complete the chamfering thereof prior to completion of cutoff.