Our first parts were grille teeth for the 1953-60 Corvette. To understand why this was more complex than it sounds, you have to know a little bit about the 1953-60...
"There were five different size teeth for the grille. But Chevrolet did what they normally did to service parts like this...they made three basic sizes (center, tooth #4 and tooth #1, but not teeth #5 and #6). This is what they catalogued as service parts. Well, of course they weren't right and if you had to replace an entire grille it just wouldn't look right. There was one person, at that time, who made some solid aluminum teeth but they weren't very good either. So I had to find myself a good set of original teeth as a start point. I had a little bit of trouble even finding a set. I used to travel a bit to Cincinnati on casting business (Jerry once owned a company called Kohn Kastings). On one trip I stopped to see a guy I met in Indianapolis who had a real choice '57 grille bar with a full set of original teeth... That's basically how it happened. I needed grille teeth and I assumed that someone else would. The difference between what I did and what other products were available was that I got a full set of original pieces, made a complete set of molds and did quality castings. We didn't do slush molds or cheap ceramic molds. We did it right. It was as close to what GM did as you could make."
— Jerry Kohn, Founder Corvette Central
Those original grille teeth and assemblies are still manufactured in Michigan, included in a mix of over 4,000 parts we currently produce.
Although the original process has been enhanced with the addition of a state-of-the-art CNC machine and electronic controls for the die casting machine, the original dies from 1975 are still in use. Recently we had a chance to photograph the grille teeth manufacturing process from start to finish.
American made zinc bars arrive on pallets as you see here. They go directly into the furnace to be melted down.
DIE CAST MACHINE
This machine has a perfect name. It's an American 150-ton die cast machine. It has its own environment within the Corvette Central manufacturing facility to control heat, noise and emissions.
The die cast machine was completely rebuilt and updated to run electronic controls in 2002.
This is the original 1953-60 tooling that Corvette Central founder Jerry Kohn built in 1974.
There are five sets of inserts that are used to produce the varying length teeth found on 1953-60 Corvettes. The tools weigh about 800 lbs. total.
In this image you can see one half of the die being loaded into the machine with a forklift. Told you they were heavy!
REDUCE, REUSE, RECYCLE
Along with new zinc bars, the grille teeth that do not pass a visual inspection get turned back into molten metal. This reduces waste and additional cost.
Liquid molten metal viewed from the surface. The zinc is melted at 787.15 degrees.
After the zinc is melted, it gets transferred to this holding furnace. Molten metal is routed from here to the injection assembly.
While not clearly visible here, once the dies have been correctly positioned and aligned within the die cast machine, the molten zinc can be injected into the dies.
COOL THEM DOWN
Here Jimmy uses a mix of die lubricant and compressed air to assist in cooling the hot grille tooth before it is removed from the dies.
TOOTH REMOVAL AND CHECK
Jimmy removes a tooth after cooling. The new teeth will be visually inspected at this point to determine if any surface imperfections exist.
FRESH OFF THE LINE
Here is one of the freshly cast teeth before the gate and runner scrap have been removed.
Greg separates the teeth that have passed a visual inspection from the scrap.
Scrap metal to be remelted.
These teeth have passed inspection. They will eventually have some of the flash trimmed with a press.
The production of grille teeth continues. About 500 pieces of any die cast part will typically be produced in a given run.
Teeth are placed in this press to trim flash from the grille bar opening.
Here is one of the teeth after this process has been completed. It is starting to resemble a finished product at this point, but it needs the excess flashing removed before heading to the CNC machine.
Cartons of grille teeth are transported in this manner over to the CNC machine.
This is our Brother TC-S2A-0 CNC tapping center. It has the ability to change cutting tools on the fly. On a grille tooth, two separate operations take place: first, it faces off the back of the casting, effectively removing the flashing and gates. Second, it taps the two 1/4" threads required to mount the finished grille tooth.
CNC PART 1
Here, the milling cutter is about to machine the back face of the grille tooth as described above. The tooth is held in place with a machining fixture.
CNC PART 2
The two 1/4" threads are tapped next. After this, the tooth is ready to be sent to our chrome plating service.
Here are three of the teeth after they have returned from our chrome plating service pictured with one of the zinc metal bars. They are now ready to be installed on your C1!