Gacha/Surprise Ball Machine

Print this machine from my wife who is a schoolteacher. She used it as a reward system in her room. It uses standard 45 mm balls that you can find on Amazon.

This is my first ever ground up design. It was very challenging with very large pieces. Took quite a bit of filament to dial it in.

You will need a piece of 220mm X 130mm plexiglass and 4" spring.

Edit/V2:

• Changed some of the parts for easer assembly.
• Added instructions on assembly.

Knob Assembly

All the parts needed for the knob assembly.

Glue knob shaft to knob.

Insert knob in small hole with slot side up.

Take the above gear(above) and move it in to position (below).

Align the slot on the shaft and the tab on the gear and push all of the way in.  

Glue on shaft end cap.

Glue on the direction restrictor. 

Bottom Gear Box Assembly  

Insert top gear as shown.

Flip top over.

Push gear on shaft. It goes on tight so make sure it loose enough to spin freely. 

Glue gear to shaft.

Top Gear Box Assembly 

Glue shaft to spindle top.

Insert spindle into big gear. 

Place big gear on gear box bottom plate. 

Flip over gear box bottom. Glue spindle retainer in place.

Place bottom gear box in place. 

Note: This is a very tight fit and may take some trimming. I do not glue this part because it fits so tight.

Glue gear box top into place.

Glue spring post into place.

Install 4" spring.

Glue plexiglass in place.