Abstract: Stitch-machining the walls of a cylindrical blind cavity of a workpiece, the cavity being deep and narrow with respect to the axis of the cavity, is carried out by: (a) supporting a tubular housing for axial movement throughout substantially the axial extent of the cavity interior and in close-fitting tolerance to the walls of the cavity, the tubular housing having a free end; (b) rotationally driving a spindle (10,000-40,000 rpm) in the tubular housing for conjoint axial movement with the tubular housing, the spindle extending beyond the housing end for carrying a radially adjustable cutting tool; (c) inserting the tubular housing together with the rotationally driven spindle into the cavity (at lineal speeds of 400-800 inches/minute) with a cutting tool radially positioned for rough boring of the cavity walls, while guiding and steering the tubular housing and spindle to accurately concentrically position the cutting tool with respect to the cavity axis; (d) substantially immediately upon the execution of r

Abstract: The large rotational inertia applied to a driveline component during normal driving conditions is simulated in a test stand that contains a component that driveably connects an input motor and an output motor. A computer repetitively executes an algorithm that produces a commanded torque signal which is supplied as a control signal to the motor drive of one of the electrical motors to produce an output within that motor equal to the commanded torque. The control system applies to the powertrain component under test an inertia that simulates the actual vehicle inertia. The target state of the system, when the vehicle inertia is applied, is completely defined from information known when the component being tested has substantially less inertia applied.