We have devoted this year to going over fundamentals of gear and gearbox design and manufacture. Before we move on to other topics, I would like to consider the effect of emerging technology on these fundamentals. While I have always found the “buzz” about 3D printing somewhat annoying, something I saw on the October 3, 2018 episode of Wheeler Dealers amazed me. If you are not familiar with this automotive “fix it” show imported from the United Kingdom, the lead “presenter” is a used car dealer. He finds a neglected car or truck and has his “mate” break out the “spanners” to restore it to “tip top” shape “on the cheap.” Production values have improved over the years; they no longer have the “mate” repainting the car with spray cans, but their devotion to economical and quick fixes appeals to me. I once re-painted my 1963 VW Microbus with a brush and a roller after doing rust repair in my parents’ driveway using aluminum sheet and a pop rivet gun. From twenty feet away the results were breathtaking. Typical American auto repair shows are heavy on product placement; engines and transmissions are replaced with new sponsor-supplied bits. Paint jobs only begin after hundreds of hours of block sanding. New wheels and tires cost thousands of dollars. The Wheeler Dealer project cars tend to have little aftermarket support, so the “mate” has to actually fix the old parts. [Sound familiar, gearbox repair shops?]  For this particular episode, there were no parts available for the Capri’s sun roof mechanism. Our frugal presenter took the broken bits to a shop offering custom 3D-printed plastic parts. They performed a 3D scan of the bracket, corrected the resulting file for the damage, and printed a replacement on the spot for $125. Skeptical me assumes that is a “promotional rate,” but the part worked without further modification. Its complexity would have made machining a replacement very time consuming, provided you could even measure it accurately enough. No drawing or sketch was made during the procedure. It was scan, tweak the file, and print the part. If this technology can work on larger parts, the most valuable machine tool in a rebuild shop may soon be a 3D scanner. (Photo courtesy of GE Additive, www.ge.com/additive)