The six-spindle SPM Series single-pass bore finishing machine from Engis can finish the bores on as many as 480 gears per hour with tool life routinely exceeding 60,000 parts. According to the company’s press release, the bore finishing tools are capable of achieving bore geometries to within 0.0002" in standard, blind and semi-blind bores. The machines feature a series of pre-set barrel-shaped tools with a slow wearing diamond coating that pass once through the bore while the tool, part, or both, rotate. As the single-pass bore finishing tool need not expand or contract over the finishing cycle, the system maintains maximum control over bore size and finish. A range of standard and customized single-pass bore finishing machines are configurable to a range of gear production processes. The SPM Series is designed for finishing parts with bore sizes up to 1.5", configurable in four-, six- or eight-spindle models. Customized automation packages are available for both in-bound and out-bound product flow. Additional benefits include more predictable results, fewer rejects, less frequent part inspection and SPC values of more than 2.0 Cpk.