Selecting the Right Abrasive for Flex-Honing

Flexible hones are used to remove loose, torn, and folded metal as well as deburr cross drilled holes on bores or cylinders and improve the internal surface finish of products ranging from brake rotors to firearms. Although they differ in terms of abrasive type, all Flex Hones feature abrasive globules that are laminated onto the ends of flexible nylon filaments.

Selecting the right honing tools for your surface finishing, edge-bending, and deburring projects requires an understanding of the different abrasives used on these “dingle berries”, as the abrasive globules on the ends of the flexible filaments are sometimes called. Whether your application is cylinder honing, plateau honing, cross-hole deburring or deglazing, the base material determines which abrasive to choose.

Common choices for Flex-Hone® abrasives include silicon carbide, aluminum oxide, zirconia alumina, boron carbide, tungsten carbide, levigated aluminum, and diamond. Abrasive type isn’t the only specification to consider, of course, as parameters such as grit size and tool diameter are also important. These and other Flex-Hone® features will be discussed in future blog entries. For now, however, let’s focus on abrasive types.

Abrasive Types

BRM recommends using silicon carbide (SC) for mild steel, stainless steel, and cast iron; and choosing aluminum oxide (AO) for aluminum, brass, bronze, and softer metals. Zirconia alumina (Z-Grain) provides longer tool life than silicon carbide, and may be used with low-carbon to medium-carbon steels, cast iron, and stainless steel. Boron carbide is recommended for medium-carbon to high-carbon steels, as well as heat-treated steels to 50 Rc. Flexible hones with boron carbide abrasive are often used with titanium, Inconel, and Monel.

Tungsten carbide is recommended for use with high-carbon steel alloys, so-called “space age alloys”, and exotic metals. Flex-Hones® with levigated alumina abrasives can be used to produce a final polish on many different materials. Finally, BRM recommends diamond Flex-Hones® for carbide, ceramic, hardened tool steel, and heat-treated steels. By choosing honing tools with the right abrasives, companies such as Miller Industrial Products have been able to quiet even the noisiest Cadillac, as described in our last blog entry.