JM Performance Products Inc  

JMPP's patented High Torque© retention knobs are uniquely designed to eliminate toolholder expansion at the small end of the holder, the inherent design flaw in V-Flange tooling that has been widely recognized throughout the industry.  High Torque© retention knobs solve many milling issues such as vibration, chatter, runout, poor finishes, inconsistent tolerances, lengthy set-up time, deviations from tool-setter to machine, and a myriad of other common problems.  By optimizing spindle-to-toolholder contact, every shop can improve their milling results.  Plus, these knobs are guaranteed to improve finishes, decrease cyle time, and extend tool life.  If your CNC tools stay true to their programmed paths, and offsets and heights are dependable, your operators will be more proficient and your CNC machines more efficient.  Close the skills gap by eliminating milling problems that start at the spindle.

Toolholder expansion occurs when a standard retention knob is installed into the small end of the V-Flange toolholder.  The torsional stress exerted by the threads at the thinnest cross-section of holder material will often cause a bulge or distortion in the holder.  Once expanded or distorted, the holder will no longer engage fully with the spindle, stopping short of the gage line.  This allows for the toolholder to move randomly within the spindle due to lack of contact over 75% of the toolholder.

High Torque© retention knobs are designed with a relief beneath the precision pilot that forces the threads deeper into the bore of the toolholder where a thicker cross-section of material resists expansion, allowing the toolholder to fully engage with the spindle.  The knobs are intended to be installed with a socket and torque wrench to a calculated axial force provided by JMPP.  By eliminating the random movement within the spindle, and creating solid contact of the holder and spindle at the gage-line, common milling issues are resolved.  

Common Symptoms of Toolholder Expansion - An examination of the V-Flange toolholder that has been expanded by the standard retention knob will reveal a wear band at the small end of the holder, a wider wear band near the gage line of the holder, and little to no wear pattern between.  The toolholder comparison illustrates this condition.  Another technique to determine if there is a tooling issue is to perform this quick Toolholder Taper Contact Test.  It is important to note that most expanded toolholders do not need to be scrapped.  Due to the elastic properties of steel, once the standard retention knob is removed, the toolholder should return to its natural form.

CNC spindle maintenance is can be a dirty, boring, and often overlooked job.  However, a clean spindle is essential for proper taper contact between the spindle and v-flange toolholder.

Build-up of chips, dust, and oil in the spindle can jeopardise taper contact and result in premature wear, repair downtime, and even CNC machine breakdown.

Ultimately, breakdowns cause production to stop and the ensuing costs are very high since no parts are being produced. The most cost-effective way to increase CNC machine productivity is through proper maintenance, ensuring optimal toolholder to spindle contact.

It’s important to note that all V-Flange tooling is designed to fit the spindle taper within tolerances of one-tenthousandths (.0001”) of an inch. Any debris, in the form of dust, grease, chips, or other contaminant left on the spindle, taper, or flange can cause poor T.I.R. (runout), poor tool life, and poor tolerances.

Recognising that a clean, smooth spindle surface is essential for proper taper contact between the spindle and v-flange toolholder, JM Performance Products, a US manufacturer of CNC mill spindle optimisation products since 2009, has developed its advanced Spindle Cleaner Kit and Spindle Restoration Kit.

The spindle cleaners and spindle restoration tapers are made from anodized aluminium that will not collapse in the spindle during use. They also come with removable handles that can be used with all cleaning and resurfacing head tapers.

Designed to remove loose oil, debris, and other contaminants from CAT and BT spindles in 30, 40, 45, 50, or 60 taper sizes, JMPP’s Spindle Cleaner Kit includes: 1 or 2 AT3 precision tapers; removable handles; 16oz bottle of degreaser; fabric cleaning strips; lint free towels and a carrying case.

The Spindle Restoration Kit, designed to remove high spots attributed to debris and rust that has galled to the surface of the spindle and cannot be removed through cleaning, includes: two precision taper restoration heads; two spindle restoration handles; 16oz all-purpose cleaner; four different micron finishes of material strips and a carrying case.

S & S Tool in Conneaut, Ohio, an established specialty CNC machining operation since 1985, had been experiencing ongoing crashes on its five CNC machines. President, Paul Sedmak noticed there were high spots in the spindle which caused the taper to sit unevenly. Seeking a swift solution to avoid repeated shutdowns, which could cost approximately $6,000 per machine, Sedmak contacted JMPP President, John Stoneback, who made an onsite visit and demonstrated the Spindle Cleaning Kit’s simple process.

Mr Stoneback began by cleaning the spindle which was heavily coated with baked on coolant as it had not been cleaned in four or five years. He then began resurfacing the spindle using the taper fitted with 40 Micron aluminium oxide strips.

He had to use the all-purpose cleaner to remove debris, including metal fragments, off the strips, but after about half an hour, he got smooth rotations.  At that point, he used new strips to really shine the surface.  A final cleaning with the cleaning head and towels left the spindle looking like new.

He says: “When you consider that it would have taken a day to pull the spindle, one or two weeks to regrind it, and yet another day to reinstall the spindle, a few hours of time saved S & S Tool a considerable amount of money in terms of down time and lost production.

“The main purpose of regular spindle maintenance is to ensure that all equipment required for production is operating at 100% efficiency at all times. Therefore, it’s

essential to implement a frequent spindle cleaning and restoration maintenance system that operators should conduct at least once per week.”

Mr Sedmak concludes: “The results were readily apparent and we implemented the kit into our maintenance schedule immediately. We’ve been using it for over three years and won’t go back. For a small investment, all of our machines run more efficiently, the tools run truer, and we’re saving on cutter wear.”