This technical information has been contributed by
John Prosock Machine, Inc.

Modern Machining Powerhouse Builds High-Tech Operation from Humble Origins

Machining     Machining

The company offers precision primary machining operations, as well as machined prototyping and engineering assistance

John Prosock Machine, Inc. ( is quite literally a modern American success story. John Prosock and his wife, Barb, started the once humble company in 1982 in the cramped basement of their first home. On any given day, the couple could be seen working together, machining parts on their conventional lathes and milling machines. Today, John Prosock Machine is a modern CNC machine shop operating with 33 employees situated in a 19,000 square foot plant on five acres in Quakertown, Pennsylvania--serving customers requiring high-tech machining in Pennsylvania, Delaware, Maryland, New Jersey, New York, and Wisconsin.

The company's measured growth eventually allowed them to move into a larger, upgraded building in 2000, and it added 11,000 square feet of additional production space in 2008. John Prosock says that due to the shrinking economy, 2009 and 2010 were hard years with many challenges, but he feels so confident about the future of the company that he installed two new high-production CNC milling machines into the plant in January of 2011.

Both new machines are CNC vertical machining centers. One has a 20 inch x 40 inch work table, and the other is a 16 inch x 30 inch unit.  One is a Japanese machine, a Hwacheon; the other, a Samsung machine made in South Korea. Before the new milling machines arrived, the family-operated contract machining company could make steel parts up to 60 to 80 pounds. The Hwacheon machine will allow the company to handle heavy duty work, up to a 200 pound part. So the company's president is now planning to seek out the larger parts.

"I decided to buy the new milling machines because I have a feeling that this is going to be a busy year," says John Prosock, the company's president. "Our other machines are already running at full capacity; these new machines will be running much tighter and more quickly, and so will have excellent repeatability. We'll be using the machines for pretty much anything and everything. We bought them because we want to be able to increase our workload capacity, especially with the larger parts."

Company Makes Parts for a Wide Variety of Industries

The contract machining company performs precision work for a variety of different industries and applications, from customized horse shoes to parts for musical instruments. Especially noteworthy are the parts and components the company makes for the aerospace and aviation industries, such as a small, gold-plated, aluminum RS-232 connector for satellites, and overhead switch panel assemblies for aircraft.

"The gold-plated connectors were made for a company that needed complete machining," says Prosock. "We told them that they can buy these things off-the-shelf, but they said they were to be used in outer space for a satellite. So the parts had to be perfect. They wanted the parts to be gold-plated so they would be corrosion proof. They eventually tested them in an acid bath to see how long they would last in outer space. And the tolerances were extremely tight -- +/- 0.002-inch in some places."

The overhead switch panel assembly was manufactured for a Piper Meridian aircraft, a panel structure above the windshield that holds a variety of switches. The machining company has also made parts for an aircraft company that makes actuators that go in wing flaps. "We make the screws, tubes, and other parts for the actuator switches," Prosock points out. "This is a critical application because the flaps have to work every time the actuator is engaged. The tolerances were only +/- 0.002-inch, but each part had to be perfect when they were finished—no deviation from the design whatsoever. We also make critical, medical actuator parts for hospital beds, wheel chairs, and MRI machines."

The company is prolific in churning out parts that vary from one extreme to the other. The machine shop makes parts for elevators, and specialized aluminum horse shoes for race horses. Prosock says that horse shoes that are cast in aluminum do not come in very many sizes, so the company machines the additional sizes. Prosock Machine has even made some really big horse shoes that appear to be for Clydesdales or Percherons. "We also make a lot of parts for the music industry," Prosock explains. "We make the steels for Hawaiian slide guitars; rods that go into the necks of guitars; and plates and finger picks.  Another company in the musical instrument field has me making tools for the guitar industry, little scissor jacks that extend about three inches. We also make medical testing parts, and we started making our own clamps for the hobby model industry."

Milling, Turning, and Assembly Help Create Completed Components

Prosock Machine offers a broad range of conventional and CNC machining services, including vertical, horizontal, and thread milling; Swiss and lathe turning; sawing; drilling; and deburring. The company also operates a dedicated assembly area with fully-equipped work flow stations. All of the stations have an assortment of hand and power tools to perform a variety of assembly operations to build a stock of turnkey assemblies and subassemblies.

In addition to the company's primary machining services, it can provide customers with a selection of secondary processes, including heat treating, grinding, honing, black oxidizing, anodizing, and plating. Assembly testing, polishing, and laser etching services are also available. The company's inspection department offers state-of-the-art quality assurance equipment that includes a Deltronic MPC5 Comparator and a Microstar CMM.

State-of-the-art CNC milling machines perform an aggregate of complex milling operations, from slot cutting to drilling, threading, rebating, and routing. The machining company offers three different types of CNC machining centers: horizontal, vertical, and thread. CNC turning equipment includes Swiss, lathe, and metal turning centers. Company literature says that Swiss turning provides Prosock's customers with higher productivity, tighter tolerances, and better quality, on machines that have a 1.25-inch diameter capacity. Lathe turning, according to Prosock, is the most basic form of turning, allowing the company to perform numerous operations, including boring, facing, parting, threading, and much more. 

"Setup in most CNC machine shops can be time consuming and prone to error, especially if one operator's setup technique differs from another's," says Prosock. "To diminish unnecessary downtime and eliminate potential problems and inconsistencies, we train every employee in setup reduction techniques. Each setup operator documents all information accurately, manages machine tools safely, reads and interprets machine programs precisely, and troubleshoots problems competently."

Design and Engineering Assistance Creates Better Manufacturability

Prosock Machine offers various ways to help its customers reduce the inherent costs of manufacturing while still delivering a high quality, finished part. The company's president states that customers aren't exactly sure what they want sometimes, so the company can offer them engineering assistance. "For example, our customers will draw up the part with sharp corners in places where it is almost impossible to put them in," states Prosock. "So we'll call them up and make suggestions. For example, we might tell them we can save them money if they put a radius in the corner instead of a sharp corner."

Sometimes they'll want to tap the entire length of a hole, Prosock affirms, when it's only necessary to tap one and a half times the length of the screw. "Some of the things that they come up with can't be manufactured very easily, so we can help them redesign the parts for better manufacturability," he adds.

If a customer can get its parts machined and assembled at the same place, it is obviously going to cut down on the cost of the parts or assemblies. "Not only will it save money, but if a company gets the parts machined and assembled at the same place, the chance of getting something wrong or a bad fit is reduced," Prosock explains. "If there's a slight glitch during assembly, we can fix it very quickly. Most of the assembly that we do is mechanical assembly, like for gearboxes that we make for a control box for concrete spraying."

Creating prototypes for a wide variety of industries puts Prosock Machine in the forefront of many machining companies. Although the company hasn't developed prototypes for the aerospace or aviation industries, it has consistently constructed them for the music and actuator industries. "An OEM will come to us with a print, and then we'll help them evaluate the part from a production standpoint," says Prosock. "Sometimes they will ask for a material that is not even available. We'll slowly refine their design into a part that is useable and cost efficient."

Before modern, rapid prototyping equipment became a reality, the machine shop made a machined prototype for a customer that makes electrical switches and other related parts. A plastic dimmer switch was needed by the electrical product company, a part that needed to be produced in one piece. "There were about ten prints, and each print had about three layers inside of it," Prosock remarked. "So I asked him if he wanted me to make just one part, and he said yes. I told him that it wouldn't be cheap. Even the fixturing was complicated and tricky, because the part was so light and delicate," he continued. "The part was only 1 inch high x 2 inches wide x 3 inches long, and it needed a lot of different machining operations."

Prosock quoted the complex part for him, and although it was expensive, the new customer said to go ahead with the project. "The part was very expensive for just one part," says Prosock. "I asked him why he wanted me to make it for him, and he said, 'I just wanted you to check my prints for me.' So, by making one part, we found all of the mistakes in the prints at every step of the way. It seemed to me that $4,000 was a lot of money just to check a part. But he said that putting out $40,000 to make a complete mold would have been more expensive if it wasn't right."

This technical information has been contributed by
John Prosock Machine, Inc.

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