[starbox] The magazine is celebrating its 30th anniversary this year and many special features will be published about technological breakthroughs that occurred during that time. I’ve been a subscriber from the first issue and look forward to having my memory jogged with the next few issues. One of my favorite features in the early years was the sequence of Leonardo Da Vinci sketches on the cover. The artist/engineer/inventor was way ahead of his time in many areas and has inspired several books, movies, and television shows. (Indeed, if Hollywood, Cable TV and the New York Times Best Seller List are any indication, he’s hotter than ever.) Only now can some of his inventions be made operational. Research into gear technology at the turn of the previous century revealed that all of the manufacturing methods we currently enjoy were already in use. The machines were slower and less accurate. The tooling was softer and less capable. Even slide rules weren’t readily available until the 1880s. Yes, they were grinding gears in 1900 — by several different methods, too. The logo of the Citroen automobile company is a reflection of the herringbone gear type the firm pioneered. As mentioned here in previous blogs, there were many different tooth forms in use. It was a time of great experimentation in all forms of mechanics. Not everything worked, of course. The tools and materials were often not up to the task. We see this most frequently today in measuring instruments, but our predecessors had little need to measure in microns when the process capability was in thousandths. The Auburn-Cord-Duesenberg Museum in Auburn, Indiana has preserved a 1930s design studio complete with clay models and an analog coordinate measuring machine (CMM) that was used to develop full-scale car bodies. Beautiful boat tail speedsters were sketched, modeled in clay, and scaled up to full size using a device made from scraps of wood and sections of dowels. It functioned like a modern CMM, but required someone to write down the results and proportion them to “full size” — a clever, low-tech solution to a problem that vexed designers for years. A friend used a homemade version of the device to scale up a model car; he had a commission to construct a version large enough to mount on an adult go-kart and the 1930s technology did not let him down. I fully expect to see more of Leonardo’s inventions brought to life in the years ahead. Great ideas are timeless. Some are only awaiting our ability to implement them.