Jay Leno has a lot of old cars with a lot of obsolete parts. When he needs to replace these parts, he skips the error-prone machinist and goes to his rapid prototyping 3D printer. Simply scan, print and repeat.
By Jay Leno
Photographs by John Lamm Published in the July 2009 issue.
It’s an amazing way to fabricate parts. The 3D scanner next to Jay creates a digital model of this flanged nut from Jay’s EcoJet supercar. The nut takes 20 minutes to scan and reverse model and 3 hours to print in plastic.
One of the hardships of owning an old car is rebuilding rare parts when there are simply no replacements available. My 1907 White Steamer has a feedwater heater, a part that bolts onto the cylinders. It’s made of aluminum, and over the 100-plus years it’s been in use, the metal has become so porous you can see steam and oil seeping through. I thought we could just weld it up. But it’s badly impregnated with oil and can’t be repaired. If we tried, the metal would just come apart.
So, rather than have a machinist try to copy the heater and then build it, we decided to redesign the original using our NextEngine 3D scanner and Dimension 3D printer. These incredible devices allow you to make the form you need to create almost any part. The scanner can measure about 50,000 points per second at a density of 160,000 dots per inch (dpi) to create a highly detailed digital model. The 3D printer makes an exact copy of a part in plastic, which we then send out to create a mold. Some machines can even make a replacement part in cobalt-chrome with the direct laser sintering process. Just feed a plastic wire for a steel part you use metal wire into the appropriate laser cutter.
Inside the printer, the print head goes back and forth, back and forth, putting on layer after layer of plastic to form a 3D part. If there are any irregularities in the originals, you can remove them using software. Once the model is finished, any excess support material between moving parts is dissolved in a water-based solution. Complexity doesn’t matter, but the size of the object does determine the length of the process. Making a little part might take 5 hours. The White’s feedwater heater required 33 hours.
Any antique car part can be reproduced with these machines pieces of trim, elaborately etched and even scrolled door handles. If you have an original, you can copy it. Or you can design a replacement on the computer, and the 3D printer makes it for you.
People say, “Why not just give the part to your machinist to make?” Well, if the machinist makes it wrong, you still have to pay for it. The scanner allows you to make an exact copy in plastic, fit it and see that it’s correct. Even when you take plans to a machinist, it can be tricky. Say the part must be 3 mm thick here and 5 mm there. You get it back and then, “Oh no, it doesn’t fit; it’s too thick,” or “It’s too thin.” My setup lets you create the perfect part. And you could press the button again and again and keep making the part twice the size, half-size, whatever you need. If you have a part that’s worn away, or has lost a big chunk of metal, you can fill in that missing link on the computer. Then you make the part in plastic and have a machinist make a copy based on that example. Or you can do what we do input that program into a Fadal CNC machine; it reads the dimensions and replicates an exact metal copy.
Some guys are so used to working in the traditional ways. They’re old-school. So they’ve never seen this new technology in use in fact, they’re not even aware it exists. When you work on old cars, you tend to work with old machinery like lathes, milling machines or English wheels. When someone tells you that you can take a crescent wrench, for example, scan it, then press a button, copy it, and make a new wrench, these guys say, “Well, that’s not possible. You can’t make the little wheel that moves the claw in and out. You’d have to make it in two sections.”
But they’re wrong. You can duplicate the whole tool.
They stand in front of the machine and watch a wrench being made, and they still don’t believe it. It’s like The Jetsons. George Jetson would say, “I want a steak dinner.” He’d press a button and the meal would come out of the machine, with the roasted potatoes and everything, all on one plate. We may not have the instant steak dinner yet—but my NextEngine system is like the car-guy equivalent.