Tiny Ivory Cog Puzzle

Tiny Ivory Cog Puzzle - 26 April 07

My first mistake was trying to use some recycled ivory piano keys. Turns out my design was going to be smaller than anticipated. A digital micrometer comes in handy when the cogs are 3.6mm in diameter!!!

Here you can see the front and back of the puzzle. The aim being to move the sliders until black dots on the cogs line up with the holes on the front of the puzzle.

This is the tricky bit. The first item is the sliders. These are small square blocks which are attached to tiny discs on the front of the puzzle. They fit into three 0.6mm wide grooves cut into the front of the puzzle. I drilled the holes sligntly smaller than the 0.5mm wire I was using and sanded both ends once they were fitted either side of the back plate through the grooves.

Cog mounts, or thin strips which sit between the grooves to stop the slider blocks from rotating were glued into position. Holes were drilled for placement of the cogs.

Now I made three cogs with varying numbers of teeth. The idea is that moving one of the sliders will effect the position of one or two cogs. To achieve this two sets of tiny teeth are required. 1) teeth on the sliders to catch the cogs. The back of these need to be sloped so the cog will simply slide over them in the reverse direction. 2) lock teeth on the cog mountings. These were required to provide positive lock when the cog was moved into position (e.g. to stop the gently sloping slider teeth from accidentlly moving the cog even when in reverse).

This particular configuration takes over 20 moves when shuffled as far away from the solution as possible. With the front and back on, it's a bit of a challenge! Check out the video below to see what happens inside the puzzle when you move the sliders.