Niles-Simmons NC 800

The Niles-Simmons NC 800 is a CNC gear grinding machine built for large external and internal gear forms — the type encountered in heavy industrial gearboxes, wind turbine drivetrains, marine propulsion systems, and mining equipment where gear modules (tooth size) and pitch diameters far exceed the capacity of standard automotive-class gear grinders. The NC 800 designation references its capacity to handle gears up to approximately 800 mm pitch diameter, positioning it in the large industrial gear segment alongside Liebherr and Gleason gear grinders of similar scale.

The NC 800 uses profile gear grinding — a generating process in which a formed CBN or conventional abrasive wheel is dressed to the exact involute profile of the target gear tooth and then traversed across the gear face in successive plunge and traverse passes. Profile grinding is the method of choice for large-module, high-accuracy industrial gears where the generating gear grinding approach (used in automotive-volume gear grinders by Reishauer and others) is less practical due to workpiece size and gear geometry. The NC 800 accommodates gear modules from approximately 3 to 30 mm, covering the full range from industrial power transmission gears to heavy mining and marine reduction gears.

The machine table holds gears up to 800 mm pitch diameter and 1,200 mm face width on a precision rotary axis. The grinding column carries the wheel spindle with CNC-controlled infeed, tilt, and traverse axes to control the grinding contact across the full tooth profile. Automatic diamond dresser units maintain the wheel profile with CNC-programmed dressing cycles. For helix angle grinding, the machine's CNC interpolates the rotary table rotation with Z-axis traverse to generate the correct helix.

CNC control is Siemens SINUMERIK 840D sl with Niles-Simmons' proprietary gear grinding software. Operators input gear parameters (module, number of teeth, pressure angle, helix angle, quality class target) and the software automatically generates the grinding program, dressing cycles, and measurement strategies. In-process gear measurement with automatic pitch and profile compensation is available to hold DIN/ISO quality grades.