Grit size and finish when you’re using Flex-hones is not at all comparable with the finish that a particular grit in a grinding wheel or belt will give. At a given grit size [say 180 grit] a grinding wheel will give a fairly coarse-looking finish but a Flex-Hone in 180 grit will give you quite a fine finish.
Because the type of material and original finish can differ widely from job to job, the only real way to determine what works for you on a particular job is by actual trial and measurement. If your starting surface has a coarse finish you may need to use a range of Flex-Hones with progressively finer grits before you get to the finish you require.
The chart below is only intended to offer a starting point in selecting grits
The Flex-Hone Tool always requires the use of a lubricant or honing oil.Cross Tools stocks the genuine Flex-Hone oil, however other acceptable lubricants include: water soluble oils, motor oils and cutting and tapping fluids. The goal is to prevent tool loading and to ensure exposure of fresh cutting particles.
No matter what the nominal grit of the Flex-Hone, you can vary the fineness of finish just by using a heavier cutting medium. For instance if you smear a bore with heavy grease you will get a lot finer finish than if you use 30 grade oil to “lubricate” the Flex-Hone. And … while we’re on this subject NEVER use kerosene or a light weight solvent when Flex-Honing. These mediums do two things. They make the Flex-Hone wear much quicker and they leave abrasive particles embedded in the pores of the metal.
Stroke rate is a function of Flex-Hone diameter, stroke length and cross hatch angle specification, if any. High cross hatch angles require faster stroke rates. The larger diameter tools might feed as slow as 100-120 IPM while the smaller diameter tools with high cross hatch angles might require feed as high as 250 IPM.
The Flex-Hone Tool is a low RPM tool. Specific RPM is dependent on the diameter of the tool and the application. General speed ranges are given below, however once again trial is required to determine what best suits each situation.