Abstract: An extensible boring bar is moved between fully retracted and fully extended positions proximal and distal to a machine housing. The bar is supported at a point within the housing and a snout and damper assembly is provided at the outermost face of the housing. The snout and damper assembly forms a compound damper system whereby an annular ring around an outer quill serves to damp the bar when simply supported in its fully retracted position, by damping the end support bearing directly. In the fully extended position, the bar is generally-cantilevered beyond the snout and damper assembly, and deflection of the bar will occur between the interior, support point and the snout support. Thus, the snout carries an additional annular damping chamber around the bar between the annular damping ring and interior or support point to damp the intermediate crown or deflection of the bar when fully-extended.

Abstract: A work contact shoe floats in an elastomeric mount within a shoe holder, and the shoe holder is mounted by bracket means to a machine base. A preload mechanism is employed for forcing the work contact shoe into a slight preload against a workpiece so that as the workpiece is machined and vibrations are generated, the vibrations will be attenuated by shearing of the elastomer.