Oval Track puzzle (a.k.a. Topspin)

This is modelled on the TopSpin puzzle from Binary Arts. The puzzle is no longer being manufactured and Binary Arts no longer exists as a company. This puzzle is an absolute gem, and I use it as a teaching aid in the classroom. Rather than handing out the expensive ones I've procured on ebay, I wanted to make my own so I could hand them out to students without fear of them disappearing. I'm quite pleased how this model turned out.

This puzzle consists of 20 numbered circular disks in one long looped track. You can slide all the pieces around the loop, or use the turntable which can rotate any four adjacent pieces so that they will be in reverse order. The goal is to mix up the ordering of the disks, and then place them back in numerical order. If you enjoy puzzles like the 15-puzzle or Rubik's cube then you've got to try this one.

I've printed quite a few copies, on various colours of PLA, and the results are excellent. The movement of the pieces is very smooth. It is so smooth that I haven't even felt the need to use lubricant.

Note: to ensure smooth movement of the pieces I've found that using an exacto knife to angle the rails where they meet the turntable is helpful. This is shown in one of the images. There are 4 rails to trim at an angle. Applying a bit of sanding (400 grit) to this area will help with the disks catching as they move in-and-out of the turntable. 

This is a relatively quick print, about 2.5 hours total. The numbers take about 45 minutes, the main body 1 hour and 15 minutes, and the turntable is about 30 minutes.