April 2009 – New MMT metal-bond honing mandrels are the supermen of superabrasive tools, factory-qualified to produce micron-level accuracy right out of the box, and custom designed for fast metal removal and long life in Sunnen or other honing machines.  Custom-engineered for high-volume, high-precision honing with minimum burr condition, MMT tools are ideal for the most demanding parts, such as fuel injector barrels, piston pumps, cartridge valves, pinion gears and gun barrels.  Precision-machined, with a body and feed wedge made from hardened tool steel, MMT tools typically last five times longer than conventional designs and reduce per-part cost by 30 percent, while producing accuracies of 0.0006 mm (0.000027 inches) for diameter, roundness, straightness and taper.  MMT tools are available for bore sizes 4 to 65 mm (0.157 – 2.56 inches), with larger sizes available on a special order basis.

            MMT tools are custom-engineered for each specific application, each with a unique part number based on width, length, expansion angle, number of stones and placement of stones.  Design options include one- to 12-stone versions, designed for use with metal-bond diamond or CBN superabrasives.  Retention springs hold the honing stones firmly in place, and factory verification allows the tool to produce precision parts right out of the box, without the time-consuming need for truing.

            MMT honing stones are replaceable under two different programs: Sunnen Precision Reload and Field Reload.  Precision Reloads for ultra-high tolerance honing are returned to the factory, and the stones are individually fitted to the stone slots, cylindrically ground to specification and returned to the customer.

             Field Reloads are installed by the customer as a drop-in replacement, so the stone assembly is designed to have clearance to the stone slot.  Field reloads are suitable for honing applications involving tolerances in the 0.008 mm (0.0003 inches) or greater range, such as pinion gears and connecting rods.

            For additional information on Sunnen tools and abrasives, contact: Sunnen Products Company, 7910 Manchester Rd., St. Louis, MO 63143.  Tel: 1-800-325-3670; fax: 314-781-2268 or emailsales@sunnen.com.