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Although honing has been associated with lapping for many years because it was once used to polish away only a thousandth or two (0.05 mm) of material, that's not the case today. Honing is now a productive manufacturing process used to improve the bore geometry and surface texture of holes in workpieces. It also removes residual stress caused by drilling, reaming and internal grinding. Honing has become a fast and efficient method of precise bore sizzling in a wide variety of parts - from turbine engine components to catridges valves.
Because the cutting points of the honing abrasive grains are so small and so many cut simultaneously, heat and stress generated in the workpiece never become concentrated. As a result, the process does minimal damage to the surface, and the integrity of the honed surface excellent.
Honing is a metal removal process used after casting, sintering, drilling, boring or reaming to obtain precise bore geometry and surface finish. In the last decade, honing has become a process better described as bore finishing, because total stock removal, and stock removal rates, have increased sunstantially. It's now practical to remove 0.016" (0.4 mm) or more during rough honing from a hard steel bore, 1" diam (25 mm) by 1" long in 40 secs. Roundness, straigthness, and cylindricity can be held to 0.0004" (0.01 mm) or better during roughing operations and less than 0.000040" (1 micron) during finishing.
An additional advantage provided by honing is improved surface texture. Most honing processes create a helical crosshatch pattern in the bore. THis texture forms a good bearing surface, because it allows axial lubrication transfer. The choice of abrasive grit size determines the surface finish obtained. Surface finish values can range from R^sub a^ values of 2 to 32 (mu)in. (0.05 to 0.8 (mu)m), and R^sub z^ (DIN) values of 16 to 252 (mu)in. (0.4 to 6.3 (mu)m).
Plateau-type surface
profiles can be created by properly combining rough and finish honing. Valleys produced by rough honing remain after finish honing removes the peaks. These valleys retain lubricant along the crosshatch pattern within the bore.
Materials ranging from Alnico to Zirconium, in diams from 0.060" to 5' (1.5 mm to 1.5 m) or more can be honed, if you choose the correct...