Useless Machines

I want to build my own useless machine, but with an articulated finger which snakes out to switch itself off. I'll start with a backscratcher

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1. Long term goal, build a cool Useless Machine like

Girlfriend: "Can't you make something more useful?"

2. So first, build a backscratcher made of my new 3d printed articulated finger design.
See the original Fusion 360 Design at: and the STL at Video at

3. Useless Machine!!

Ain't it beautiful?!  Ok, there's something slightly of-the-squids-from-the-Matrix about it, but I think I've designed a fascinating mechanism to transmit rotation from one end to the other via the structure.  This hopefully allows a servo at one end to drive the whole finger to flex.

Now these fingers can be used to build both a back scratcher and the Useless Machine...


Standard Tesselated Geometry - 586.70 kB - 02/01/2019 at 06:56



Standard Tesselated Geometry - 571.37 kB - 02/01/2019 at 06:56


v3 standalone.png

Portable Network Graphics (PNG) - 311.42 kB - 02/01/2019 at 06:56



Standard Tesselated Geometry - 1.02 MB - 02/01/2019 at 06:56



Standard Tesselated Geometry - 441.68 kB - 02/01/2019 at 06:56


View all 6 files

  • 1 × Motor 37-1216 RVFM Right Angled Motor and Gearbox 1:220
  • 1 × RVFM SP5-72GL140-A V4 Microswitch 37.5mm Lever
  • 1 × SCI TA202A1 3A DPDT Miniature Toggle Switch On-on
  • 1 × Battery pack from: flexbatterAAAx3.stl
  • 1 × various small screws (4)

View all 6 components

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Mike Szczys wrote 02/04/2019 at 19:55 point

I love it! Any reimagining of the most useless machine is worth a test build! Also, for some reason this mechanism reminds me of the linkage robots Neal Stephenson talks about in his book Seveneves.

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