If there’s one thing Corvette Central founder Jerry Kohn wants you to know, it’s that the company he started 40 years ago does more than sell restoration parts – they manufacture many of them. In fact, there are about 2,500 parts Corvette Central produces, with the vast majority being brackets and other supporting parts that play vital roles in restorations.
Corvette Central’s expansive southwest Michigan headquarters covers 75,000 square feet, including manufacturing, research and development, offices, warehouse and shipping.
“I like to say we fill in the blanks and provide the unseen components you need for a restoration,” says Kohn. “Just because you don’t polish it doesn’t mean a part isn’t important. For many restorers, our parts are the only sources for brand new components cast to factory specifications. In many cases, they’re better than the original part, but with the same look, feel and manufacturing process.”
Like so many success stories, Kohn’s entrepreneurial achievement was rooted in personal need. He was trying to fix up a second-hand 1958 Corvette back in the early 1970s. It was typical of many used Corvettes that were about 10-15 years old at the time: It had a later-model LT1 engine and a four-speed swapped into it, and it wore slotted “mag” wheels. Sheet metal screws were holding on the door panels, which said a lot about the car’s overall condition.
If You Want It Done Right, Do It Yourself…
Kohn wasn’t necessarily looking to concours-restore the Corvette – it was only a relatively inexpensive, 15-year-old used car at the time – but he wanted to bring it up to presentable condition. The problem was restoration parts. They basically didn’t exist, especially when it came to tracking down high-quality replacement grille teeth. Chevrolet only serviced three of the five different sizes of the die-cast grille teeth used in the early cars, but they had been already snatched up years earlier. Someone had produced reproduction teeth, but the quality and construction were nowhere near OEM standards.
Kohn was a man who made things for a living. As a matter of fact, his profession let him understand the intricacies and challenges behind manufacturing components such as the grille teeth.
The Reference Wall. Corvette Central maintains an exhaustive collection of original parts pulled from countless donor vehicles over the years. They’re used as templates and references for designing new parts, and, of course, the new components are checked against the originals for accuracy.
Corvette Central founder Jerry Kohn began restoring C1 dash inserts years ago and continues to work on them himself. In the early days, he would gingerly tap out dings in the thin, curved aluminum panel, but reproduction inserts make the job easier. Kohn estimates he’s personally done “thousands” of the inserts over the years.
“As a tool and die maker, I could immediately see the difficulty in producing them,” Kohn says. “Because of their depth and relatively thin walls, the teeth were surprisingly complex and difficult to manufacture. I’m not surprised GM didn’t service the teeth for very long. I imagine the supplier had a hell of a time knocking them out consistently at the necessary quality level. If the supplier went out of business, I’m sure no one else was looking to pick up that particular baton.”
But his experience as a tool and die maker also gave Kohn the insight to produce them more accurately, and with his drive for outfitting his Corvette with the right parts, that’s exactly what he did. After casting the teeth for his car, Kohn started putting more examples in the trunk and showing them off at swap meets. The response was immediate and enthusiastic – and the rest, as they say, is history.
Along with the wall of reference parts, Corvette Central also maintains rolling-shell test cars that also serve as reference points, enabling fitments and tolerances to be checked, as well as providing an invaluable resource about the assembly process and techniques of the cars.
Here’s where much of the manufacturing magic happens – Corvette Central’s die-casting machine. It is a “hot chamber”-type casting machine that is fed by a pool of molten metal to form the parts.
Some Things Stay The Same
That’s not to say producing the teeth is easy, even 40 years later. “The manufacturing process is largely unchanged, and so is the design and shape of the parts,” he says. “We’ve gotten better over the years, but those teeth were and remain some of the toughest parts to cast, because of their thin walls and deep draw. They look great on a car, but I don’t think the designers had any idea of the manufacturing implications.”
Kohn had another reproduction hit on his hands in the 1980s, when he started producing factory-spec exhaust pipes and related components.
“Back then, it was hard to get factory-correct exhaust pipes,” he says. “It seemed obvious, but no one was really taking care of that part of the restoration business, so we started doing it ourselves. Today, exhaust pipes are one of our biggest-selling lines.”
Yes, almost four decades later, Kohn and the business that became Corvette Central, continue die-casting those grille teeth, producing exhaust pipes and thousands of other parts. The company is based in Sawyer, Michigan, which is closer to Chicago than Detroit. In fact, it’s no coincidence that Kohn forged his business there. With plenty of nearby sand from the area surrounding Lake Michigan, the southwest corner of the Wolverine State was a casting and tool-and-die hotbed in the heyday of manufacturing in the United States. The foundries have all but closed up in 2014, although ironically the only surviving tool and die shop in the area is owned by Kohn’s brother.
As it has been for more than 100 years in the industry, the metal at the heart of most die-cast automotive parts is a zinc alloy, which includes some aluminum. Corvette Central brings it in by the truckload to cast hundreds of different parts. It’s used because zinc melts at a lower temperature than many other metals and produces a component that provides a good balance between strength and lower weight. Nothing goes to waste - Corvette Central recycles casting flash, cast parts that didn’t meet quality specifications, and other metals that come through the facility, melting it all down to make the next batch of parts. A furnace next to the casting machine takes the zinc and other recyclable metals and liquefies them at more than 800 degrees F.
Keeping Trades Alive
Corvette Central has expanded over the years, covering approximately 75,000 square feet and employing about 80, some of whom are specialists in manufacturing trades that are disappearing all too frequently these days. It’s one of the largest employers in the area and turnover is low among the skilled workforce.
Here’s the tool and die for a C1 grille tooth – the very parts that put company founder Jerry Kohn on the path to Corvette reproduction parts manufacturing. The two components are joined in the casting machine, where molten metal fills the negative space between them to create the new part.
Manufacturing doesn’t merely involve casting brackets and grille teeth. It’s followed up with finish and assembly procedures, where necessary. Frames for heater controls are cast on site, for example, and are matched with all-new levers, screens and other hardware to produce entirely new control panels. In almost every case, the reproduction parts are assembled with the same types of hardware and assembly techniques as the originals.
Left - A couple of freshly cast cross flags emblems illustrate the “out of the mold” appearance prior to finish work. The flashing will be trimmed before the parts are brightened and painted. Right - Here’s what finished emblems look like after they’ve been chromed and painted. The zinc alloy used by Corvette Central is comparatively corrosion-resistant, too, which will help these emblems retain their luster for a long time.
Some of the finish work, including drilling and tapping bolt holes, is handled by CNC machines. This one happens to be working on a grille tooth. After it’s machined, it will be sent up the road to a chrome plating facility in Grand Rapids, Michigan, before returning for final inspections and packaging.
When it comes to parts that are composed generally of a single cast part – like the grille teeth or perhaps a cross-flags emblem – they are trimmed, machined for attachment hardware and even sent out for chrome-plating. And while Corvette Central was founded on manufacturing, its catalog and Web sit balance the products produced in-house with other manufacturers’ components, including appearance and performance accessories.
“We make a lot of parts, but we can’t make them all,” says Kohn. “We complement what we don’t produce with other high-quality parts to give our customers a one-stop source for restoration parts.”
As we mentioned earlier, much of Corvette Central’s manufactured components are the arguably less-glamorous but no-less-important parts when it comes to assembling a 55-year-old Corvette.
A perfect example of the unseen parts that Corvette Central produces is this bin of brackets that form the foundation for the turn signal-canceling switch assembly for 1956-62 cars. Sexy? No. Necessary? Yes.
“It’s a lot of the brackets and other metal parts you don’t see,” says Kohn. “We are the exclusive manufacturer of a number of parts, especially for C1 and C2 models, including shielding, mirrors and related parts.”
The bracket used with C1 turn-signal-canceling switches is a prime example. Decades after the cars went out of production, the demand for the part remains strong, while the call for new components to reproduce is as strong as ever.
“When the NOS supply of parts is exhausted or another manufacturer quits producing a part or goes out of business, we’ll jump in to fill the void,” says Kohn. “It’s a constantly changing business for cars that went out of production half a century ago.”
Corvette Central is one of the only manufacturers of original-style vintage rearview mirrors. Each is produced with the same processes and assembly techniques as the originals. Officially licensed parts carry the factory-correct bowtie logo on the outer housing.
Heater/climate control panels are also manufactured on site, using die-cast frames produced in-house and additional supplied components. These parts are a godsend over the often tough-to-operate originals that are found in many early Corvettes. Here, one of Corvette Central’s technicians assembles a heater control panel, using the same methods that were employed more than 50 years ago on the originals.
An Evergreen Part
A testament to the strength and endurance of the business is those grille teeth – the parts that launched the business. The company produces several hundred each year, just as it has for the past several decades.
“We still sell as many of them every year as we ever did,” says Kohn. “It has surprised even me, because you’d think they’d all be accounted for by now, but no. There are still cars being discovered in barns and brought back to life, just like I did 40 years ago.”
Along with manufacturing parts, Corvette Central has branched into component restoration services, such as repairing and strengthening C1 windshield mounting brackets. The tabs on the originals typically snap off and Corvette Central addresses the dilemma by carving out notches in the frame where the original tabs break off and bolting on stronger steel tabs. The surgery results in a much-stronger repair that’s completely invisible when the car is reassembled.
Corvette Central also offers a number of restoration services, including repairing C1 windshield frames, which tend to snap off where they attach to the body. The fix involves machining a section of the frame and installed a hardened steel insert that’s much stronger than the original mounting tab. The photo on the right shows an original windshield frame (minus the original mounting tab that was broken off long ago), next to a machined frame (arrow) and the new mounting tab installed by Corvette Central. The fix is much stronger than the original tab and it’s completely hidden after the windshield frame is installed.
What Comes Next?
Kohn wonders, however, how the restoration business and the hobby, in a broader sense, will evolve as upcoming generations of enthusiasts embrace the refurbishment of later-model cars, such as the C4 generation.
“It’s difficult to hazard a guess, because at the moment, the core of the hobby is still focused on the vintage cars and demand remains strong,” he says. “But as the supply of those cars dwindles and their cost goes up, it’s logical to believe cars like the C4 will become more attractive.”
Corvette Central is also big on factory-spec exhaust systems and they all start with these big stocks of mild steel tubing. Computer-controlled tubing benders meticulously and perfectly shape each raw exhaust tube into a factory-correct shape. An upgrade from the original crimped-type bends, however, is modern mandrel bending, which enhances exhaust flow.
Another unique product made by Corvette Central is the 1956-62 hupcap spinner. Several raw parts are shown at right, awaiting test fitting prior to chroming.
Unlike C1, C2 and C3 models, however, the C4-and-later cars are composed of much more plastic and electronically controlled components, making them generally more difficult to work on. That’s not to say Corvette Central doesn’t support C4, C5 and C6 owners. They certainly do – a fact to which this writer and former C4 owner can personally attest – but it’s clear the early parts are the company’s bread and butter.
“We’ll go where our customers ask and give them the parts they demand,” says Kohn, who has a penchant for pace cars and maintains an enviable collection of Corvettes and other Chevys housed at the company’s headquarters. “That’s been the foundation of our business for 40 years and it will drive our success in the future.”
All that from some homemade grille teeth, created when the market couldn’t give him what he needed. That’s the essence of the entrepreneurial spirit. It’s assuring to know it’s alive and well – and it’s found in the small town of Sawyer, Michigan.
The final step for every part that’s produced at Corvette Central is the shipping department. Even with the turbulent economy in recent years, the company has encouragingly been on an upward trajectory, which bodes well not only for the Corvette hobby, but the prospects of entrepreneur-based businesses in general.