Wisconsin Manufacturer Solves Boring Problem With Extensions

V&L Tool, Inc., located in a Milwaukee suburb, had to solve one of its toughest boring problems before beginning the manufacturing of a new hydraulic jack. The jack's main cylinder required a bore 12.5 inches deep and 2.753 inches in diameter. The material was 4140 pre-hardened steel. They had to hold tolerance within 0.002, all the way down and achieve a microfinish of 63.

V&L's customer had spent more than a year researching, designing, and field testing a pre-production prototype and they confirmed strong market demand for the new jack. Railroads wanted a safer and more efficient replacement for a ratchet-level mechanical track jack.

The challenge was to produce the jack within exacting specifications at a cost that would be acceptable in the marketplace.

A contract job shop, V&L specializes in manufacturing mid-range production runs from model prototypes to about 10,000 pieces, serving a variety of customers, mostly in the medical, automotive, hydraulics and electronics industries. The company employs about 90 in three adjacent buildings with 70,000 square feet of manufacturing space.

Mark Forney, V&L's manufacturing engineer on the job, asked KPT Kaiser Precision Tooling (Elk Grove Village, Illinois) to assist and two weeks of insert trials began. Finally, Mr. Forney was satisfied with the speed, feed, and performance of the modular tooling solution selected.

They used Kaiser's 312.615 production boring head with two 331.660 extensions, one 331.661 extension, and a 326.902 coolant inducer. The insert was the CTP51 cermet, 655.312. The optimum speed was determined to be 527 rpm and feed rate at 2.69 ipm. Running four on a pallet, it now takes V&L about ten minutes to complete four bores.

"We played around with feeds and speeds until we were blue in the face before creating reliable working conditions. Up the rpm a couple and it doesn't work, but we found the perfect solution," Mr. Forney said.

V&L is now running up to 12 parts per day. The cylinder bore is the most critical operation but only one of several using Kaiser modular tooling. Mr. Forney is using the Kaiser 112.311 head for a couple of half-inch bores on the same piece.

"It's easy to adjust. If you want 0.20, you can get them. Sometimes there's a problem in the material--a hard spot or something. All you do is take it out and run it again," he says. V&L solved the customer's problem and the solution was a "win-win" for both, with an unexpected dividend, by actually reducing their net cost as well as a significant improvement in quality. MMS