Improve rigidity for standard EMT you know.... wood. A 3\4" dowel, sanded if necessary, would for. Rout a groove for wires if necessary. If no one has tried it, I'm your huckleberry

[kubark42 (Kenn Sebesta)]

Regarding Goddard, Wright Bros, Yeager, and all those others pushing the understanding of fluid dynamics, they were working on the cutting edge of very complex systems. We’re just trying to keep a stick from bending.

If my bet at trillion-to-one wasn’t tempting enough, would you take quadrillion-to-one odds?

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I dunno know if you saw these two threads:

Modular XZ block (from 1/2" EMT to 1.25" tube)

Received the printed parts: [20200416_125538] Unfortunately, the incorrect configuration got printed, so I will have to wait on some new clamps. But the upside is that the middle span doesn’t need to be swapped out, so the printing effort is low. Score one for modularity! One thing to report is that the center span is super stiff. I think it might take some engineering to get the overall assembly to be equally stiff, but it might not actually matter. Once the first model is together, I’ll se…

Adjustable bearing block (from 1/2" EMT to 1.25" plain tube)

Final version: [Screen Shot 2020-04-16 at 12.49.07] Note that I got rid of the recess. That was because ultimately the distance of the tube from the plate is driven by the need to allow clearance for the Y belt. It would take a further redesign to get this sorted out, and it’s likely a major change since it involves new belt geometries, and not just an optimized block. Note in the assembly how the bearings are retained by zip ties, but the zip ties are non-load bearing. The two screws at th…

The idea was to allow people to use up to 1.25" tube. That’s about 2x the rigidity for 25% more weight. A lot less swearing involved than shoving a wood dowel slathered with epoxy into a metal tube. (I’ve been there, I hated it. It amazed me how a thin layer of epoxy maked for an impossibly tight fit!)

When the local unis shut down this spring I lost access to the 3D printers and so stuff on my end is stalled until they open back up. If you had an inclination to experiment with these larger diameter steel tubes, I’d be really happy to support it and draw up any new parts you might need. BTW, 1" EMT is also supported by this modular system, and it’s a lot easier and cheaper to come by than 1.25" tube stock.