Versatile Tools Speed Turning

Manufacturing Engineering, Feb 2005

Established in 1999 by Josef and Susan Kaltenegger, their two sons Hans and Jeff, and son-in-law Nico Morowat, Kaltech Mfg. (Delta, British Columbia) specializes in whiteiron machining and other tough, quick-turnaround jobs for local pulpand-paper industries and other applications.

One of the shop's most difficult jobs involves threading of large bolts used to secure heavy cables on hydroelectric dams. The operation requires removal of a lot of material to produce the 460 × 14-mm trapezoidal threads.

For turning, the shop was searching for a tool that could handle roughing of the entire workpiece, then finishing the thread root. "We were ordering an insert from Sweden, and it just wasn't convenient or cost-effective," operations manager Hans Kaltenegger recalls. "We didn't think there were any inserts in North America that could do the job."

Then a tooling rep introduced Kaltech to the A4 groove and turn tooling system from Kennametal Inc. (Latrobe, PA). Designed for high productivity on machines with limited tool positions, the system is rigid enough to provide stable cutting even with high machining pressures and relatively long overhangs. Secure clamping and bottom-V seating of the insert enable higher feed rates and depths-of-cut.

Although the A4 system was engineered for turn, face, profile, OD and ID groove, bore, and cutoff applications, Kaltech uses it in 95% of its production of large external square threads. Used for primary roughing, the system cuts finishing time by removing the bulk of the material before finish passes are made with a threading insert. "The tooling enables our machinists to precut the coarse thread on very large bolts," Hans Kaltenegger says.

According to Kaltenegger, Kaltech was able to push the tool to accommodate a thread feed rate of 50 ipm (1.3 m/min) at 88 rpm. Machinists are now threading eight pieces per A4 edge, helping to reduce production time by 70%.

"The bolts are machined from large amounts of material, and we often have a lot of overhang, which usually causes chatter," Kaltenegger explains. "The tools minimize chatter and leave a very good finish."

Used to machine 50 bolts, A4 tooling saved Kaltech roughly 25% in costs. Kaltech saved approximately 20% per part in labor costs and approximately $300 per part in insert costs. Hans Kaltenegger estimates a competitor's tool would have taken five inserts per part to complete the job. Circle 224