Flexible Honing: Suggested RPM, Stroke Rate, and Lubrication

Size, speed, stroke rate, and lubrication are important considerations when selecting and using flexible hones. The relationship between size and speed is a simple one – and easy to remember. The smaller the Flex-Hone®, the faster the speed. The larger the Flex-Hone, the slower the speed. Got that? Now let’s take a look at some other rules of thumb for using flexible hones to improve internal surface finish and deburr bores and cylinders. The Flex-Hone tool is easy to use, so these tips are easy to remember.

Flex-Hone RPMs
The Flex-Hone is a low revolutions-per-minute (RPM) tool. As a rule, the specific RPMs are a function of tool diameter and application. Although Brush Research Manufacturing (BRM) suggests some general speed ranges, machine trials may be needed to verify the right RPMs. Every application is different, of course, so we hope you’ll share with us what works best for you.  Which size Flex-Hone are you using? The smallest tools have a hone diameter ranging from 4 millimeters (mm) to .5 inches (in) and run at 800 to 1200 RPM. The largest Flex-Hones have a hone diameter of 19-in to 36-in and generally run at 60 to 120 RPM. Flexible hones come in many intermediate sizes, of course, so download BRM’s free Flex Hone Custom Resource Guide for a complete list of speed ranges.

Flex-Hone Stroke Rates
Measured in inches per minutes (IPM), Flex-hone stroke rate is a function of the following factors.
· hone diameter
· stroke length
· crosshatch angle specification (if any)
As a rule, high crosshatch angles require faster stroke rates. Larger-diameter Flex-Hones may feed at 10 to 12 IPM while smaller-diameter tools may feed at 250 IPM.

Flex-Hone Lubrication
We’ve saved the simplest rule to remember for last. The Flex-Hone tool always requires the use of a lubricant or honing oil. Whether you use water-soluble oils, minerals oils, motor oils, or cutting and tapping fluids, it’s important to keep the Flex-Hone from loading and to expose clean cutting particles. Remember, too, to avoid solvents since these substances degrade the adhesive bonds that laminate the abrasive globules onto the ends of the Flex-Hone’s nylon filaments.
For the very best results, use BRM’s specially-formulated Flex-Hone Oil for all types of metals. This emulsified blend of honing and lapping oils also contains a lard oil to prevent aluminum galling, moisture dispersant, a non-ionic surfactant wetting agent, and an anti-bacterial agent.