A printable dial counter, like the old style odometers. Arbitrary number of digits possible in theory though slop in the parts may create a practical limit.

Tools required:

A set of needle files (and maybe one normal file for more aggressive material removal) and/or sandpaper. These parts are designed to be assembled without glue or fasteners and how well they fit will depend on your printer's abilities. You will probably need to at least remove burrs and strings for good fit. Hopefully that are just a hair too tight and you can file them down.

Instructions:

Determine the number of digits you will want. We will call this N.

Print N of:

1. Number Wheel

Print N-1 of:

1. Axle Plate
2. Geneva Wheel
3. Pinion

Print 1 each of:

1. First digit cap
2. Last Digit cap

Alternate: You may also use an additional axle plate(s) instead of the cap(s) on either end. I made the caps to save material and reduce print time.

Once everything is printed, tidy them up and assemble! Refer to the rendering to see how it all goes together. This assembly has small features and might not turn out so well for larger nozzles or less-tuned machines... but please share your success/failure stories!

Video in action:

http://youtu.be/tbzUhtlWPW0