Summary

Grinder V 4.30 E

The V 4.30 B grinder is the start of this version. You will need to make that first. For this version print two large gears, both large and small shafts, one motor gear and the motor box.
This add-on might fit on the other models this is based on like rmcht’s Double Gear Grinder and the Dual Drive system of claxly. There would be more overhang opposite the drive gear. I haven’t tried this unit on any of those.
This is a simple glue-on addition once wired. Install the switch and motor with the USB cable into the motor box first. I used a drop of crazy glue to secure the motor in place as well as the USB cable at the opening.
Glue unit in place where the motor gear meshes tightly with the small gear, apply glue to top edge against hopper and the bottom against the top of the drawer section. The motor has considerable torque for its size, glue well.
The motor box needs some file or sandpaper work around the corners.

The motor is available from AliExpress, eBay etc. for around $5. A common part number is GA12-N20. I used a 6 volt @ 300 rpm motor. They are available in numerous rpm speeds. 300 rpm spins everything fast enough. 6 Volt works with USB. After using the grinder for a while I would go with a 200 rpm motor for more torque.
https://www.aliexpress.com/premium/GA12%2525252dN20.html?spm=a2g0o.tm1000000741.1000002.0&initiative_id=SB_20230303134112&dida=y

The switch used was a 6 pin DPDT ON-OFF-ON toggle MTS-203. Two switches for $3. MTS-203 is the only switch that will fit.
https://www.aliexpress.com/premium/mts-203-toggle-switch.html?catId=0&initiative_id=SB_20230304130432&SearchText=mts+203+toggle+switch&spm=a2g0o.productlist.1000002.0

Wire the switch as shown in diagram. The two wires that crisscross on the bottom of the switch must be insulated from each other. A 3 position switch with a center OFF is easier on the motor and gears and is recommended. A 2 position DPDT switch causes bad voltage spikes that could hurt the motor from jarring it back and forth with no Off in between.
This allows the motor to turn both directions. I find that repeated 3 to 5 seconds runs in each direction makes the grinder work best.
The USB cord was salvaged from an old phone charger and was hooked up directly to the switch.

Like the handcrank versions they work best with your “material” broken up into small chunks minus the stems.
Download .pdf for all this info plus part pics.

NOTE : I have tested the unit with a few different types of buds and sometimes it will bog down and even stop requiring instant motor reversal. A simple fix for that is to use a DC-DC Boost Converter to raise the voltage up to around 7 volts from the USB's 5 Volt.
XL 6009E Boost Converter About $2 each. Set Voltage before hooking up motor.
https://www.aliexpress.com/w/wholesale-xl6009e-boost-convertor.html?catId=0&initiative_id=SB_20230322222244&SearchText=xl6009e+boost+convertor&spm=a2g0o.productlist.1000002.0
The USB wires into the IN on the converter and the output goes to the motor.
The motor is conservatively rated for 6 volts so 7 volts will not hurt it for normal use.

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