FLIP-20 Springfield edition · build manual

A little purple split-flap telly that runs on elbow grease. The yellow crank flips through 20 Simpsons pictures, one click each, and the yellow knob waves the rabbit ears. Every part is printed: no screws, glue, wires or batteries.

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Reference

The 20 pictures

In flip order, 10 × 14 pixels of 4 mm each. Every picture is split across two flaps: its top half on the front of one flap, its bottom half on the back of the flap before it. Tap one to crank the TV round to it.

Reference

How it works

Everything moves by hand. Two small mechanisms do the work, and both are printed.

Crank to pictures ratchet

The crank's hex peg goes through the cabinet's side, across the side bay and into the axle. The axle runs through the divider wall, with its tip in the spool. A 20-tooth ratchet wheel on the axle passes a flexing pawl in the bracket: it clicks once per picture going forward and stops the spool going backwards, where the flaps would jam on the stop fingers.

20 teeth18° per pictureturn anticlockwise (top forward)

Knob to antenna Scotch yoke

The knob sits on a printed shaft that ends in an off-centre disc just under the roof. The antenna's shaft comes down through the cap and ends in a fork that straddles that disc. As the knob turns, the disc's centre moves side to side and the fork follows it, so the ears swing one way, back, the other way and back on every turn.

3.5 mm off-centre±24° swingturns either way
Reference

What you need

Tick things off as you gather them. The ticks are saved in this browser only.

No screws, glue, wires or batteries. Everything presses, clicks or slides together, so the TV comes apart again the same way.

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Fits and clearances

Measured on the 3D model with the knob turned all the way round (every 15°), the crank all the way round and the chassis sliding in: nothing collides. Parts that aren't meant to touch are at least 1.2 mm apart. Parts that turn, slide or press together use the fits in the second table.

Reference

Not tested yet

The model says these work, but none has been printed. If one is off, say what and by how much, and the part gets adjusted.

  • How the pawl clicks and how strong it is (a 1.0 mm PLA flexure).
  • The bracket's pegs in the divider's holes. If they're loose or crack, two M3 × 8 screws in the same holes replace them.
  • The axle's tip in the spool, and the crank's hex in the axle.
  • The yellow knob on the printed shaft's D tip, and the cap's crush ribs in the roof window.
  • The two tall, thin shafts printing cleanly (53 and 49 mm, standing).
  • New on this cabinet: the splayed legs and the thinner 5 mm front.