Abstract: A high speed toolholder for driving a small high speed cutting tool from the large slow speed spindle of a machining center comprises a housing having a retention pin extending from side end thereof. An input shaft, dimensioned to be received in the machining center spindle, is rotatably journaled into the toolholder housing parallel to the retention pin. Rotatably journaled into the opposite side of the housing so as to be coaxial with the input shaft is an output shaft whose distal end has a tapered bore therein dimensioned to receive the shank of a high speed cutting tool. Within the housing, each of the input and output shaft carry a separate one of a pair of sheaves which are each lined by a V-belt to a separate one of a pair of sheave members on a step sheave rotatably journaled in the housing parallel to the input and output shaft.

Abstract: A high speed machine tool spindle assembly for firmly retaining a cutting tool therein, notwithstanding machine tool vibration, includes a spindle having an axially extending bore therethrough. Integrated to each end of the spindle is a tool gripping collet, each collet being urged radially inward against the shank of a cutting tool disposed in the spindle bore by a respective one of a pair of collet nuts which each threadedly engage the spindle adjacent to a separate one of collets at each spindle end. Each of a pair of collet nut drivers is carried by the spindle adjacent to a separate one of the pair of collet nuts and each is slidable along the axis spindle to jointly engage a separate one of the pair of collet nuts and the spindle.

Abstract: A machining center for machining the interior of an elongate tubular workpiece includes a bed on which a rotatably indexable member is slidably mounted for movement on the bed along a first axis. Removably fastened on the indexable member in spaced parallelism are a first and second hollow bore spindles each engaging the exterior surface of a tubular workpiece whose interior is to be machined. The first spindle is rotatably driven to rotate the tubular workpiece about its axis responsive to machine tool control system commands slidably mounted on the bed for movement thereon along a path perpendicular to the path of member movement in an upright. Extending from the upright parallel to the axis of upright movement for insertion into the workpiece bore is an arm which is movable along the upright along a vertical direction. At the distal end of the arm is a right angle, high speed rotary driven cutting tool carrying spindle.