Today’s Print – Gear Bearing by emmett

Thingiverse user emmett created a very clever single-print rotating bearing, a planetary gear.

bearing5_preview_featured It’s clever for three reasons:

  1. It prints in a single print
  2. It requires no support, so removing support (which is necessary for ball-bearing rings) which can be very difficult, is not necessary at all
  3. It is a series of gears with no axles

Each gear has a middle cut (if you’re thinking of 3D modeling) which is rotated around its center making each gear tooth a V shape. These fit into each other flawlessly, but also ensure that they cannot slide out of the ring. They stay put, and rotate very nicely.

Here is my print:


Using a large Allen wrench inserted into the hex hole in the middle, I gave it a good turn and it began moving. Now it rotates easily.

It inspired me to think of other ways to make bearing rings that require no support, but will not fall apart. Rather than use spheres, I decided to use cylinders, bevelled at the top and bottom to keep them within the rings, which contour to the cylinders. Each cylinder is close enough to its sibling that it should rotate freely, but they should not bunch up causing the bearing to fail.

Here’s the model:


The pyramids at the four compass points are my logo for 3D printing, a pyramid with two bits taken out to make it an “H”.

It’s a theory. I’m about to print one and see.

Update: Sadly, mine turned out like crap. The cylinders were too short and stubby, so they acted like spheres, toppling over in their tracks. There was too much open space between them, almost enough to fit a whole other one in the ring. That made it not rotate smoothly.

Oh well… back to the drawing board.



2 thoughts on “Today’s Print – Gear Bearing by emmett

  1. I like your inline concentric bearings.
    Wouldn’t cylinders increase friction? – When two cylinders touch a line is formed instead of a point?
    What about only the outer bearings being in the shape of cylinders? What about hour glasses? Or what about staggered bearings in the outer ring?
    I would like to put this on the front wheel of my bicycle and test it out.

    • Yeah, I tried cylinders. They didn’t stay aligned. My cylinders weren’t perfectly cylindrical, but even so, a line is not going to cause much more friction than a point on two spheres. The total surface area is still negligible. But it didn’t work anyway. I’m still impressed with the sawtoothing of the Emmet gear bearing.

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