Rock Tumbler / Ball Mill

Simple rock tumbler built around cheap alliexpress motor ZYTD520 I found home.

You will need:

  - 6x M3 x 10 screws (to secure the motor)

  - 1x M5 thread insert and 1x screw M5x15mm for securing the motor shaft.

  - 3x M4 thread insert and 3x M4x15mm for tightening the lid

  - 1 x motor ZYTD520,  12V, 5000 RPM with gearbox to 15 RPM
    https://www.aliexpress.com/item/32587420240.html?spm=a2g0o.order_list.order_list_main.30.40f61802ZrCVZL

  - 26 x 6mm Airsoft BB's for the bearing

  - 1x 5mm power connector (8mm outer diameter)

The assembly:

1. Print all the pieces (I used 5 perimeters to make the parts stronger), the sealing is supposed to be printed from flexible filament.  Melt in the thread inserts into the tumbler-can part (3xM4 to hold the lid, 1xM5 for securing the motor shaft).
2. Solder the motor and power connector. Secure the motor into the tumbler-MotorMount part by using 6xM3 screws and the power connector to tumbler-MotorCap and connect these two parts together (should hold together just by friction, but feel free to glue these if you don't plan to dissassemble these parts anymore)
3. Insert the airsoft balls into the groove on part tumbler-MotorMount, to form a bearing and secure them in place by inserting the part tumbler-Can over it.
4. Secure the lid using 3xM4 screws, optionally attach some nice screw caps. (I used these: https://www.thingiverse.com/thing:2186175 )

Known issues:

• heavy
• noisy
• not water tight
• problematic cleaning (the bearing gets dissassembled when removing the can)
• the legs don't feel stable if loaded with heavy content.
• no long term testing performed yet
• if running for long time the lid screws get loose

Tumbler in action: