Abstract: Apparatus for machining a valve seat and valve stem guide all from the valve seat side of a head or block. The valve seat is machined in one pass by a single point cutting tool which is moved on two axes and, the valve guide bore is machined by a reamer. The movements of the single point cutting tool and reamer are numerically controlled.

Abstract: A coupling between adjacent ends of transfer bar sections which includes a screw having threads of opposite hand at opposite ends thereof engaged with threaded counterbores in the ends of the two transfer bar sections. A spacer ground precisely to a desired length is clamped between the ends of the bar sections when the screw is tightened. The spacer and screw have radially aligned holes therein to accommodate a tool for tightening the screw. The holes are dimensioned relative to the tool so that the screw can be tightened a final increment without rotating the spacer.

Abstract: A work supporting plunger and a control plunger are perpendicularly arranged for axial sliding movement in a work support body. The inner end of the work support plunger engages an axially inclined face on the control plunger so that axial movement of the control plunger results in movement of the work support plunger to and from supporting engagement with a workpiece. A collet in the work support body concentric with the control plunger is adapted to lock the control plunger against movement. The collet is in turn surrounded by a collet locking sleeve movable axially to lock and release the collet.