Abstract: A lathe and a method of using the lathe are disclosed for forming an aspheric surface on a workpiece, in which the workpiece is mounted to a holder that is rotatably carried by the spindle, headstock and bed of a lathe, with that spindle and workpiece being rotated about the axis of the spindle with the workpiece being engaged by a forming tool which forming tool is moved through an arcuate path about an axis that is generally transverse to the spindle axis. The method and apparatus provide further for determining the time-varying angular position of the forming tool along the arcuate path, for determining the time-varying angular position of a point on the workpiece about the spindle axis and for reciprocating the workpiece holder and the workpiece held thereby relative to the lathe headstock and to the forming tool in synchronization with the movement of the forming tool and with the rotation of the workpiece about the spindle axis to form the desired contoured surface.

Abstract: A machine tool for successively machining opposite ends of short-length workpieces has a hollow spindle. A chuck having a hollow inside is provided on at least one end of the hollow spindle. The hollow space of the spindle and chuck provides a smooth and continuous guide surface for easy and successive transfer of the workpieces therethrough.

Abstract: A method and apparatus for producing thermoplastic bags from an elongate web. Apparatus for feeding the web includes devices for producing mounting holes and perforations along a circular path surrounding the holes. The web is severed and sealed to produce sheets containing a mounting hole encircled by the perforations. A selected number of successive sheets are impaled on a post projecting through the holes. A stack having a selected number of sheets is accumulated on a post fixed to a support supporting a medial zone of the sheets which are combined by a heated punch penetrating the sheets in the area enclosed by the perforations.

Abstract: A draw tape for thermoplastic bags is made by feeding tape to a first pair of nip rolls rotating at a relatively slow speed and a second pair rotating at a fast speed. The tape is stretched to form thin and narrow central portions between end portions of unstretched tape. The first nip rolls are increased in speed, or are released to interrupt the stretching. When the rolls are closed, one of them is momentarily retarded or backed up, to produce a rapid transition in the tape between the unstretched end portion and the stretched central portion.