Print Your Own Vertices For Quick Structural Skeletons

3D printing is great for a lot of things: prototyping complex designs, replacing broken parts, and creating unique pencil holders to show your coworkers how zany you are. Unfortunately, 3D printing is pretty awful for creating large objects – it’s simply too inefficient. Not to mention, the small size of most consumer 3D printers is very limiting (even if you were willing to run a single print for days). The standard solution to this problem is to use off-the-shelf material, with only specialized parts being printed. But, for simple structures, designing those specialized parts is an unnecessary time sink. [Nurgak] has created a solution for this with a clever “Universal Vertex Module,” designed to mate off-the-shelf rods at the 90-degree angles that most people use.


The ingenuity of the design is in its simplicity: one side fits over the structural material (dowels, aluminum extrusions, etc.), and the other side is a four-sided pyramid. The pyramid shape allows two vertices to mate at 90-degree angles, and holes allow them to be held together with the zip ties that already litter the bottom of your toolbox.

[Nurgak’s] design is parametric, so it can be easily configured for your needs. The size of the vertices can be scaled for your particular project, and the opening can be adjusted to fit whatever material you’re using. It should work just as well for drinking straws as it does for aluminum extrusions.

25 thoughts on “Print Your Own Vertices For Quick Structural Skeletons

  1. It looks like it might be kind of wobbly, zip ties and all, why not just design a variety of connectors that can fit inside and/or outside round and square tubing. A fixed 90 degree connector could be less wobbly than two pyramids zip tied together (I think).

      1. Good luck building an extrusion frame from that. The picture you posted is from Lowe’s, and is a USP 8-in G90 Galvanized Finish Corner Brace. It’s meant to be nailed into wood, specifically 2×4’s. Rather large and not terribly useful for small aluminum extrusions. And it’s listed at $4.64 each, which isn’t what most would call pennies a pop either.

        The other brackets and braces are generally quite expensive as well. I tend to minimize their use because even counting my time, it’s cheaper to make something from scratch.

        1. That wasn’t the point. These things come in all shapes and sizes, and there’s no reason why you couldn’t use something meant for wood to fix a piece of aluminium extrusion – just drill and tap a hole in the aluminium for a screw, or use a pop-rivet etc. etc.

          1. True. But you’re going to have to put your shop in order to work with metal (if you don’t have a dedicated area/tools for that). Drill and tap the extrusions. Enlarge the nail holes in the brace/bracket to accommodate the size screw you need, or make new holes if the existing pattern is unusable. And clean up when you’re done.

            At that point, it only takes a little more time to make your own connector. Taking something you paid hardware store prices for and *still* have to modify to be suitable, rarely feels advantageous. I’d rather break out the steel and snips, or do some proper wood joinery, like you mentioned.

          1. And, if you have any kind of saw which you use to cut dowels to length, you can use that to make a finger joint at the end. Looks much nicer. Wooden pegs in holes also works…

    1. The comparison would be apt if we had no indoor plumbing.

      In which case it wouldn’t really matter whether you sit on a throne or squat over a hole – you have to shovel shit anyways.

    2. They are called out-houses. In the previously mentioned countries.

      You are thinking of Suzhou China
      And a super high end office park with a building with a amazing exterior.
      Dormroom/Office Warehouse sweatshop.

      Actually you might find said squat holes in Hungarian areas as they are descendants from the Huns and have the foot mechanics to match.

      1. yea I was going to comment squatting isn’t incompatible with indoor plumbing. Thing is most US citizens have never had take a dump outdoors even on a irregular basis and the activity is foreign to them. Has also said everyone is born with the foot structure to squat easily. One of those use it or loose it things. I knew a man who could squat like a toddler can well into his 50’s like a toddler does.

    1. Right. With this design each vertex is made of 3 pieces printed in the same orientation. The thinner section fitting around the rod ends runs perpendicular to the XY plane, so it should resist lateral stress. The top section is much thicker, which improves the bond between the lower layers and the holes for the zip ties.

      This would be pretty tough if printed in nylon though. The inter-layer adhesion on nylon is very good if done properly.

      1. Or instead of running to some other material, you could just try designing correctly toward whatever technology you’re planning to use.

        I recently wanted some interior braces for extrusions because I wanted the outside to be clear to mount panels, so I made these:

        The way I print them is actually rotated sitting on the *hypotenuse*. They still come out quite accurate, strong, and don’t require supports.

  2. I agree that 3D printers allow for designers to generate what they see in their imagination into a prototype product, but until the material used for 3D printing and the fusing process in 3D printing produces a product of equal strength to a machined device, it isn’t the super magic manufacturing technology the hype would have you believe.

    I prefer my CNC machine. There are times I wish I had access to the multi-axis models, but when I’m done with the product it is battle ready.

    1. As always, the right tool for the job. Even if I had a fancy mill, I would probably still go to the 3d printer for things like small jigs and project cases. The setup time is almost nothing for a 3d printer, the material is cheap, you don’t need to keep a close eye on it, and there’s no mess to clean up afterwards.

    2. A fractional strength device prototyped out of plastic is better than no device at all.

      CNC machines have been around a very long time. If they were that awesome, none of this would be happening, ever.

      CNC machines are not pleasant to actually own. That’s problem #1.

      That would be OK if you could just get someone else to make your stuff for you. But that’s problem #2:

      The people who traditionally own and operate with CNC machines are a royal pain to work with.

      Given the spectrum of choices — owning a CNC machine, having to deal with someone who owns one, or just buying a 3d printer — yes, absolutely, 3d printer all the way, 100% of the time I’d choose that every time. Even if I didn’t own one, getting someone to print me parts is typically about 100,000 times easier than getting someone with a CNC machine to essentially do the same thing.

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