Tech Talk
What is a hone?
A hone is a machine tool used in the manufacture of precision bores to improve the geometry, surface finish and dimensional control of the finished part. This process is called honing. Typical applications are the finishing of cylinders for internal combustion engines, air bearing spindles and in gear manufacturing. Types of hone are many and various but all consist of one or more abrasive stones that are held under pressure against the surface they are working on. The hone is usually turned in the bore while being moved in and out. Special cutting fluids are used to give a smooth cutting action and to remove the material that has been abraded. Machines can be portable, simple manual machines, or fully automatic with gauging depending on the application. Modern advances in abrasives have made it possible to remove much larger amount of material than was previously possible. This has displaced grinding in many applications where "through machining" is possible. External hones perform the same function on shafts. [edit] Cross-hatch Finish A "cross-hatch" pattern is used to retain oil or grease to ensure proper lubrication and ring seal of pistons in cylinders. A smooth glazed cylinder wall can cause piston ring and cylinder scuffing. The "cross-hatch" pattern is used on brake rotors, and flywheels. [edit] Plateau Finish A tool with the brand name Flex-Hone made by Brush Research Manufacturing Co., Inc. was introduced as a hone with many of the benefits of honing without the need for labor intensive set up or training. The tool is often referred to as a "ball-hone" for its many abrasive globules on the end. The result of using this tool is that it provides a cross hatched finish while achieving a plaueau finish at the same time. The Plateau Finish is one characterized by the removal of "peaks" in the metal while leaving the cross hatch in tact for oil retention. The plateaued finish increases the bearing area of the finish, and does not require the piston or ring to "break in" the cylinder walls. Other similar processes are lapping and superfinishing. http://en.wikipedia.org/wiki/Hone
