No more blowups: Drilling Performance

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END USER: Marquardt Engineering Inc., (847) 669-0690, www.marquardt-eng.com. CHALLENGE: Eliminate chatter to prevent indexable inserts from blowing up and causing catastrophic tool body failure when drilling 4150 prehardened steel. SOLUTION: A new drill body and inserts. SOLUTION PROVIDER: Tungaloy America Inc., (888) 554-8394, www.tungaloyamerica.com

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New and improved is in the eye of the beholder. After using a style of indexable-insert drill for nearly 20 years, Marquardt Engineering Inc. experienced problems when the toolmaker replaced it, according to Brian Mueller, president of the Huntley, Ill., machine shop.

“The new drill chattered and would blow up inserts,” Mueller said. “The new design wasn’t better—it failed miserably.”

The toolmaker indicated that the vast majority of its customers found the new drill boosted productivity, but that was little consolation for Marquardt Engineering and other shops that didn’t experience those results, Mueller noted. “They indicated, ‘you’re the unfortunate 10 percent and there’s nothing we can do for you,'” he said.

Mueller added that when chatter destroyed an insert, primarily the one in the tool’s center pocket, the destruction usually caused catastrophic tool failure. That required replacing the drill body, which can cost up to several hundred dollars.

The problems were pronounced when drilling 4150 prehardened steel, which varies in hardness from about 30 to 35 HRC, according to Mueller. Marquardt Engineering also machines a variety of other workpiece materials, including mild, tool and stainless steels. Jobs range from screw machine parts to ones 26 ” in diameter and volumes range from one a year to 10,000 monthly.