NOTE! As this is one of my first ever builds using a 3d printer, there will probably be a few bumps along the journey of making this, or better ways to do something - so if you find anything concerning or have any advice, please comment it! Thank you :)

For this build, you will need: 

1. A 3D-Printer
2. 1/8in shaft (approximately 4 9/16in and 3 3/8in)
3. Superglue
4. Possibly a drill with bits to widen holes

To prepare your parts, first check that your spacers can fit on your shaft and gears slide freely. If not, drill out your holes until it reaches the desired fit. After checking this, superglue your black shells to each of the counters, whilst making sure they do not overlap onto the gears. These will be important as they represent a 0.

To assemble, insert your shafts to the corresponding holes on the taller base. Then, stack from the knurled bottom to the top. While doing this, make sure the gears are engaged and line up the black and white line with the next counter. Once finished, put your end base cap on (superglue if you need to, but should be a tight fit) and enjoy!
 

Here are some photos to help you if you are stuck: