Elements for the marble run toy blocksIn this article, I'll cover various elements of the marble run toy blocks.
Next, drilling out the center with an 11/32" (17.5 mm) drill. Any drill 17 mm or larger is good. Marbles are typically 16 mm, but vary in size a fair bit, so not all marbles can pass through a 16 mm (5/8") hole.
The overall piece needs to be 96 mm along the edges (three 32 mm increments). I made my blanks slightly larger than that, so that I could afterwards completely center the hole by cutting away excess from the sides. Here I'm scratching where I want to cut it with my calipers.
I also carved a slight bevel around the exit hole. Otherwise, with more than one marble in the bowl, jams happen more often.
Making the zigzag elementsFor my modular marble machine, I glued these together out of several pieces. But I figured for the toy company, it would make more sense to produce these with a CNC router. I don't have a CNC router, but I can use my pantograph to route out the shape.
A problem with my 3D pantograph is that the vertical axis is controlled by tilting the pantograph. For stuff like 3D letter carving the tilt is not noticeable, but for these tracks, I wanted all the cuts vertical...
I set it up so I was sitting in the air stream coming out of my workshop air cleaner so I wouldn't be breathing quite as much dust.
The ramps came out better as I made more of them. I don't think CNC would have cut them any faster. Guiding the router manually, I can listen to how hard the router is working and adjust my "feed rate" accordingly. Of course, a CNC machine could cut the pieces unattended, but at just a minute of cutting for each piece, I'd still be standing there watching it.
Skijump, flipflop and rocking elementsNext, the "ski jump" element, a rocking back and forth element, and the flip-flop element.
Here I'm cutting several sides for those pieces at once on the bandsaw. I had previously cut one of these from a template, and instead of printing off again, I just traced around one of the pieces I already made with a pencil.
The ramp needs to have a slight bevel near the exit to compel the marbles to roll out the exit once it stops rocking back and forth. That beveled notch should go just past the half way point across the ramp. Not too deep, or the marbles lose too much energy as they roll over it.
These elements are surprisingly good at not jamming with multiple marbles in them. Here I pre-loaded the ramps with six marbles, then put one marble in the top ramp. The cascade caused by the extra marble cleared up all but two of the marbles out of the ramps. Sometimes two marbles will jam at the exit, but the next marble will cause them to get flushed out.
After testing with the rocker in place, I cut the nail to just under 32 mm in length, and hammered it in. The head of the nail is slightly larger than the hole, so that locks it in place, with nothing sticking out either side.
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