An Obsession with Flatness – Part 3

Prototyping ain’t easy, but it’s necessary

As the saying goes, everyone has a plan until they get punched in the mouth. The same goes for taking a design and turning it into a physical object. You may not have the tools or material you need, you may realize that in reality, things don’t operate the way that you want, or the way you designed something just isn’t feasible to build. The other side of the coin is that maybe you come up with a better design while you build.

Building the DIY Repeat-O-Meter, most of the above happened. This doesn’t lead to a pretty finished product. Extra holes drilled throughout the part to try one one idea or another. Slots roughly cut, then a design change halfway through. It’s not the best work I’ve ever done. But I’ve built enough prototypes at this point, that I at least expect this sort of thing to happen.

Bottom of repeat-o-meter
Excellent machining! Good job centering that slot. Nice Extra holes on the side of the base. The two holes on the back of the arm by the foot are where the arm connects to the base via two screws, and one was re-drilled for some reason? (I think I was going to originally try and put the ball for the foot in the very back?)

The most difficult part was determining how much of a slot, and how thin of a web to leave on the arm to get reliable flexing, that would not lead to permanent deformation, but be “soft” enough to provide good readings. It took a bit of experimentation, but I finally arrived at something that seemed like it would work.

flexure hinge
The Flexure. She ain’t pretty, but she works. It took a bit of trial and error to get the right amount of flex. And once again, an extra hole from the original design.

Next up: Finally Finished.