I made pauloblank's Math Spinner Enhanced (fast print, no support) for my cousins to play with at a party, they looked it over and said "this should ratchet."
Many hours of design later I've created a ratcheting math spinner. I've made the spinners thinner to print faster, and squeeze more into a reasonable total height. I added more operators and digits for more complex math. I also had to make a central core for the ratcheting mechanism, no more pvc pipe and reprinting to get the diameter right.
Step 1: Download Files
Step 2: Slice files (normal settings, no support)
Step 3: Print Parts (6 numbers, 1 core, 1 endcap, 2 operators, 1 equals)
Step 4: Lubricate the core so that the ratcheting mechanism works more smoothly
Step 5: Slide all the spinners on, arrange however you'd like.
Step 6: Slide the endcap onto the core. Use a countersunk screw to hold everything together. #6 through #10 should work. You may need to add a washer between the core and endcap if it's to tight. This is because when printing this many seperate parts the excess height of parts adds up to a considerable amount. This will be different for everyone
Step 7: Start spinning each spinner to wear them in
Step 8: Enjoy your new math toy!