Cutting Tool Engineering
September 2012 / Volume 64 / Issue 9

Ready, aim, machine

By CTE Staff

Evolution Gun Works Inc. makes parts for nearly all leading U.S. gun makers. EGW President George Smith founded the Quakertown, Pa., company in 1991. A competition shooter, Smith is an expert in the John Browning-designed .45-caliber automatic pistol, dubbed “the 1911” based on the year it was introduced.

The 15-person shop is staffed with gun enthusiasts who enjoy hunting, recreational and competition shooting and restoring firearms.

In addition to being an OEM supplier, EGW manufactures aftermarket gun components, such as mounts for rifles and shotguns, barrels, recoil springs and triggers. Its aftermarket parts can be found in guns used by top competition shooters.

Fadal%203020%20Performance%20Series%20VMC.tif
Courtesy of Evolution Gun Works

Evolution Gun Works machines ejectors (above) for the 1911 pistol on a Fadal 3020 Performance series vertical machining center.

Machining%20Ejectors%20for%201911%20Pistol.tif

One EGW part is an ejector made of tool steel for the 1911. The shop makes about 5,000 ejectors annually on a Fadal 3020 Performance series vertical machining center with a 22-hp, 10,000-rpm spindle. EGW initially applied a 3/8 " endmill at a 200-sfm cutting speed, with 0.001 " chip load per tooth. Dissatisfied with the slow speed, Smith and his crew searched for a high-performance endmill that could run faster.

They found one endmill head, which screwed onto a 38 " shank, that was able to run at 300 sfm—a 50 percent increase in speed—and a 17.1-ipm feed with the same chip load as the previous tool. The spindle speed was 3,056 rpm. Unfortunately, without any indication of wear, the tool broke after only 192 pieces.

“Not only would the endmill head break, the holder would be shot because the threads would rip out,” said Steve Seaman, CNC department head. Therefore, EGW had to replace the $50 head and $150 shank. To prevent damaging the shank and head, EGW began replacing the tool after 175 pieces—an improvement but not a solution.

Looking to improve the process, Flood Industrial Supply Inc., Ivyland, Pa., introduced EGW to the AlTiN-coated Z-Carb-AP endmill from SGS Tool Co., Munroe Falls, Ohio. Using the SGS tool, EGW was able to run the job at 450 sfm and a 25.7-ipm feed with a 0.0015 " chip load per tooth. EGW was also able to increase the spindle speed to 4,584 rpm. The shop still makes eight parts per cycle, but cycle time decreased from 2.25 minutes per part to 1.5 minutes.

The productivity increase, however, was only part of the story. The SGS endmill lasted through 1,061 pieces at the higher speed before breaking—4 full days of work out of one cutter.

“Think of the cost savings that come from not only being able to run at faster speeds, but also from having less downtime as a result of not replacing the tool as often,” Smith said.

Ultimately, the Z-Carb-AP endmill is 5.7 times more durable than the competing tool, even when run 50 percent faster. This productivity gain reduced cycle time by 62.5 hours on an annual basis. Based on 94 cents saved in tool costs per part, EGW saved $4,688 by switching tools.

Smith says he’s the type of owner who is open to trying new technologies. If a sales representative from a competing toolmaker claims to have a better solution, EGW is willing to put it to the test. So far, he noted nothing has matched the capabilities and performance of the Z-Carb-AP.

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