Modern Machine Shop

SEP 2018

Modern Machine Shop is focused on all aspects of metalworking technology - Providing the new product technologies; process solutions; supplier listings; business management; networking; and event information that companies need to be competitive.

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BETTER PRODUCTION MMS SEPTEMBER 2018 120 mmsonline.com TOOLING FOR MILLING we test both types of knobs with a gage," says Dick Brimer, technical sales and support manager with JMPP. "The demonstration confirms that most standard retention knobs create expansion at the small end of the toolholder, causing bulges that result in the toolholder not going into the spindle all the way." Since tight tolerances are essential in high- speed machining, if the toolholder does not fit the spindle precisely, decreased productivity and reduced tool life are inevitable. Mr. Brimer explains that JMPP's retention knobs feature a relief between the top thread and the f lange that enables the thread to fit deeper into the holder, making it more stable and keeping toolholder expansion to a minimum, if it expands at all. By increasing contact with upward of 70 percent more of the spindle surface, a wide range of CNC milling issues are overcome, according to JMPP, including vibration and chatter, poor tolerances, non-repeatability, poor finishes, shortened tool life, excessive spindle wear and tear, runout and shallow depths of cut. Mitch Olson says that the demonstration had a big impact on him and his brother. "We've got a lot of money invested in the tooling, and without the right retention knob, it could affect everything on the whole mill. The demonstration showed us how JMPP's knobs provided better overall finishes, required less hours and shorter runs for us as a job shop. That's why we started with their knobs." This diagram from JMPP compares various CAT 50 retention knob designs. The company's high-torque retention knob (on the far right) is slightly longer than traditional retention knobs (shown to its left), but it shares the same head dimensions.

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