Where it all started
Years before Dennis started Raytech, he worked for a small job shop in northern Iowa. A customer approached him and asked for a “workbench” that would have a pin on a bearing, connected to an encoder, and would be able to measure sheet metal blanks. And that’s just what the client got.
Dennis found a thick butcher-board, had it planed down to be flat, routed a slot in it for the pin to come through, mounted a bearing and encoder to the underside with wood screws, and delivered the workbench. Upon delivery, the client asked, “Well, how accurate is it?” Turns out, Dennis never thought to check. After all, he was using an encoder that was supposed to be +/-0.0004″, how far off could the machine be? Oh, about thirty thousandths of an inch (or 1/32 for the tape-measure types). Needless to say, the implementation needed some work.
Make it metal
In hindsight, it seems obvious, but one of the big issues with the original design was the stability of the wood as a base for a measurement system. The initial solution to the first model was to get a piece of flat steel stock and mount the bearing and encoder to that. This way, at least the relationship between the bearing and encoder could be more stable and the accuracy of the machine did improve. Still, it wasn’t ideal and soon the next step was taken.
At the time, the tables were pretty much built by hand using simple hand tools like drills and hand taps. This led to using aluminum tooling plate as a table top material. We could easily drill and tap it using a hand drill. With a threaded insert, we didn’t have to worry about stripping threads. The material was parallel top and bottom, which meant that when we flattened the top using our leveling bolts, we knew that the bottom surface where the bearing and encoder mounted were also flat. The aluminum was obviously heavier than the wood, but not so heavy that the plates were unmanageable. We found that 1 1/2″ square structural steel tubing made a solid-enough frame to support the table top and make the machines better than they were.
Make mine bigger
Eventually, customers kept asking if we could build longer and wider machines. As we started stretching out, we ran into an issue. The aluminum plates we were using weren’t available in lengths longer than ten feet. This required us to use multiple plates to cover the extra length, which meant a seam in the middle and potential problems when getting the tops flat. Not to mention the unfortunate circumstance if one of your mounting holes for a bearing or scale happened to land on that seam.
It was at this point that we started using ground structural steel plates instead of the aluminum plates. Of course, this represented another jump in weight which required we build the frames out of 3″ square structural steel tubing, and in some cases we use a mix of 3″ and 4″ depending on how long and wide the machine is. This was also the point where we started using magnetic base drills instead of the hand drills to make the holes in the tops.
Back to the beginning
Today, we have one of the original wood top tables. It’s over twenty years old, yet if we wanted to, we could hook up an encoder cable and the machine would function. I’m not sure how accurate it would be as it sits now, but I have little doubt that with a little effort, we could return it to its original working condition.
Imagine how long the machines we currently build will last.