I’ve been thinking about another way to connect the framing structure in open-source framing systems.
There are, to my knowledge, two main systems, Contraptor, which uses L-section aluminium framing, and which has lots of holes for nuts and bolts, and MakerBeam, which is mini T-slot aluminium extrusion.
MakerBeam differs from commercially-available T-slot in being a 10mm square section. In the UK we have, for instance, ValuFrame, which comes in 20mm, 30mm, and 40mm versions. In the US they have 8020, which comes in about every shape and size you can imagine (and then some!)
What is mostly used in the world of RepRap is threaded steel rods with printed plastic joiners held in place by lots of nuts and washers.
What I haven’t seen used that much, and which is freely available as standard extrusions, are aluminium rods, both circular and square cross section, and aluminium tubes, also square and circular cross section.
What I have in mind is a system of plastic-printed vertices that will push fit onto any of these readily-available systems.
These vertices can be male (for systems where the struts are tubes) or female, for both tubes and rods. For something like T-slot, they could be a combination.
I call these “No-Nuts Contraptor” or “Push-Fit Contraptor” although, in truth, I think this idea is less appropriate to Contraptor than to any of the other systems.
I got the idea for the name from Vik Olliver’s article on the RepRap blog, Getting Rid of Mendel’s Nuts, last June, where he is using what I would call female vertices.
As an example of male vertices, there is a readily-available system for square-section aluminium, although I think the prices for the connectors are ludicrous. (And thanks to Johan de Stigter of Utrecht, who pointed me at this Dutch company. Check the prices, and divide by the quantities!) Some interesting ideas. As someone who can’t cut a straight line to save his life, this looks both useful and printable.
Vertices can be made in a wide variety of configurations. (Thanks to my friend, John Cosier, for the Sketchup file, which can be downloaded here.) This Sketchup file shows all the vertices in 0, 90, 180 degree angles, but they could be produced to any angle required. This would have the advantage that, when assembling a frame, all of the angles are pre-constructed by the vertices.
If joints are left “unfixed” then a structure can be taken apart, which makes the system much quicker. When you’re happy with a structure it can be made more permanent with super glue or Plastex.
Just as soon as I have my first 3D printer up and running, I shall start to produce the first experimental versions.
No Nuts Contraptor by James Hardiman is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.