Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/142883
As that force is applied, the contracting prong things are pushed out of the body of the cleco and simultaneously away from a set of spreader bars, which causes them to contract so that they can fit through holes in a couple of pieces of metal. Once the cleco is in place and the plunger is released, the step-cut locks expand and withdraw into the body, pulling and securing the two metal parts together. This not only joins the pieces temporarily but keeps the holes lined up perfectly, which is crucial when it comes to drilling additional holes, attaching other parts, etc. While they hold very securely, removing them is, if anything, even simpler than installing them, involving just another squeeze with the purpose-built cleco pliers. Because clecos are thankfully reusable, there's no way of knowing how many times one is installed and then removed on a given project, but the number must be well into the thousands. These little things are ingeniously clever in their design and utterly indispensable on a build like ours, but they're so ubiquitous that we absolutely take them for granted. I know I did, that is, until a friend of mine off-handedly asked, "What did they use when they built airplanes before clecos?" and I realized I didn't know. I didn't even know within a decade when they were invented, which meant I had no idea if people were even building sheet metal airplanes before they could use clecos to make it easier. Because I a) hate unanswered questions and b) had too much time on my hands, I started searching and found U.S. Patent No. 2,136,875, which I believe to be the first U.S. patent issued for what we now know as a cleco. The patent was originally filed on March 16, 1936, by a Frenchman named Jean J. Blanc, who had filed the same patent in France in May 1935. (I also found a British patent for a somewhat similar device from 1934, but my emphasis there is on the "somewhat.") With this information, the patent had answered one of my questions. With the following introductory text, it answered another: plate securing and locating device which is applied to or removed from the work from only one side thereof, thus eliminating the assistance of another workman from the opposite side of the work." So, before clecos, people used nuts and bolts, which, in retrospect, seems stupefyingly obvious. What wasn't as obvious, however, was the fact that this process frequently required two people (with all appreciation for the Rosie the Riveters in the world back then and my female friends and colleagues now, I won't say "workmen"), which differs profoundly from the way we do it now. The other important bit is that using clecos only requires access to one side of the work. Looking back on our CH 750 project thus far, the idea of forcing a second person in behind every part to tighten a nut would have been, in most cases, preposterous, and in some cases, a felony. So here's to Monsieur Blanc; my simple research has told me next to nothing about him, except for the fact that he made building metal airplanes (and whatever else you might build, but we all know that airplanes are the most important) one heck of a lot easier. Another tool that's been one of my unsung heroes of this project is the spring-loaded center punch. This is a metal gadget about the size of a pen that can be used to put a small dimple in a piece of metal (or a somewhat larger one in a careless finger, but that's a story for another day). It couldn't be easier to use—you just put the pointy end where you want a dimple and then push. There's a spring inside that connects to an internal hammer, and as you push, the spring builds up energy until the hammer reaches a certain (adjustable) point; then it releases with a pop. The pointy bit, which is actually the punch, strikes the metal and makes a small, neat depression. As for why "Heretofore, it has been found in practice that before plates or the like could be riveted together, it was necessary for the workman to first secure the plates together by screws or bolts, which were inserted in the holes provided to receive the rivets. This long and expensive operation was necessary not only to secure the plates together but also to assure a perfect coaxial alignment of the rivet holes. In a great number of cases, this operation necessitated two workmen, one on one side of the work for inserting and holding the bolt in place, and the other on the other side of the work for screwing and tightening the nut on the bolt. It is therefore an object of this invention to produce a Photography by Jennifer Bowen EAA Experimenter 43