Piston rings are a relatively small part of an engine or machine, but they are crucial to its functionality. Milwaukee-based Grover Corp. makes piston rings and seals to very strict tolerances to increase efficiency and seal any leak paths in industrial machines.
"If the piston ring doesn't work, the machine doesn't work, so it's a very critical part of the machine," said president Stuart Banghart. "The efficiency of the sealing is in close tolerance and in the surface of the finish that we hold."
As the largest manufacturer of industrial rings in the United States, according to the company, Grover has the ability to serve Fortune 500 companies throughout the country.
The company's 80 employees make piston rings and seals ranging in size from 3/8-inch to 90 inches in diameter at the Milwaukee headquarters and a plant in Fort Worth, Texas.
Grover was founded in 1929, and purchased by Banghart and several investors in 1993. In 2005, Grover acquired America's Double Seal Ring Company in Fort Worth, adding the second location and expanding its capabilities to include parts for large bore engines and larger diameter rings.
The company focuses on manufacturing piston rings for industrial applications and large engines, excluding the automotive sector. Banghart has positioned Grover to serve the needs of large, demanding customers like Caterpillar, John Deere, Atlas Copco and SKF.
Grover makes about six million rings per year using custom and regular CNC, grinding, milling, turning and boring machines. The rings are primarily made of cast iron.
[caption id="H8-308039993.jpg" align="align" width="440"] Grover Corp. makes many kinds of industrial piston rings, including these hook rings.[/caption]
First, a raw casting or a cast tube is put through grinding, then turning and boring, then milling, followed by a manganese phosphate rust coating and quality inspection before it is shipped, Banghart said.
While Grover is similar to large, high volume piston ring manufacturers like Federal-Mogul Corp., which serves the automotive market, and Briggs & Stratton, which serves the heavy duty diesel market, it tries to keep a small company feel, he said.
Customers include both original equipment manufacturers and aftermarket suppliers. The rings and seals are used primarily in hydraulics, shock absorbers, air compressors, automatic transmissions, big oil and gas engines and turbines.
"We serve the customer base that is not well-suited to those high volume manufacturers," Banghart said. "The large majority of our parts are custom made. The large automotive manufacturers were more focused on the high-volume markets, leaving customers available in the industrial market."
Grover is in the process of expanding its Fort Worth location from 20,000 square feet to nearly 40,000 square feet as a result of increased demand.
Orders are up about 50 percent over pre-recession levels and revenue has grown at least 30 percent each year for the last three years, he said.
"We were down significantly during the recession. Since that time we've grown significantly," Banghart said. "Customers are recognizing the combinations of the engineering, the quality and the service."