Manual Burr grinder to Mechanized

So, I bought a hand-cranked coffee grinder years ago.  It's a chore, but seems to make pretty good grinds. For a while, two days, to be frank, I used it as intended, then I got bored and started using my Dewalt drill, inelegant and an utter pain to be honest. So, how do you mechanize a hand grinder? Well, 3d printing of course. 

The main issue is that small motors don't have the torque to drive a coffee grinder, so I drew up a multistage planetary gearbox to give me an approximately 27-1 gear ratio. Also, the main drive on this coffee grinder has a pentagonal shaft? Why… just why. 

The whole thing is a prototype made on a whim. But it works.

Parts list… There's a lot. 

Motor https://a.co/d/7EkjVUq is what I used, any 550 sized motor should work. 

Coffee Grinder https://a.co/d/7BGug3f I haven't tried with other models. Who knows. 

Bearings X 15 https://a.co/d/8XyFeVY 

Grease for gears https://a.co/d/02A52UW This stuff is good, food safe, you do you though.

Power supply 12-24V with 2000ma of output

Speed controller https://a.co/d/bgiBFLq 

Hot glue or something similar

https://a.co/d/h7fsQzW You need some wire to make some internal connections. I used 22AWG solid. 

https://a.co/d/6qPSTtJ 4.8mm blade connectors because I didn't want to solder the motor connections.

https://a.co/d/9e8SbhW female power jack I had some of these lying around pretty sure they're all the same size? Not confirmed fit from this listing. 

Machine screws

M3x8 X16 (clearances are loose enough that you can get away with M3x12s if you want)

M3x16 X2

M4x8 X7

M4x12 X4

M4x16 X9

M4 heat set inserts I used M4x6, revision probably coming later to the part that needs these. 

Printed parts

Mostly you need 1 of each component. Exceptions are:

Planet Gears x12

Sun Gear x2

Gear carrier X2

C clips x15

Instructions

First, print all the gearbox components. Most everything is intended for no supports. Exceptions being the sun gears, maybe I'll come up with a design later that is supportless. 

Start with the planet and sun gears, insert bearings, and get the C clips in their valleys. Attach gears to the gear carriers as shown with M3 screws as shown in the picture. Insert the sun gear in to ensure everything is in sync.  Lube them up with some grease. Ensure the screws are pointing up. Shove them into the ring gear, carefully insert the next assembled carrier, ensuring that the sun gear drive shaft inserts properly into the second carrier. Then finally do the motor side gear carrier. 

Attach the motor to the motor side cap with the M3x16 screws, then press the Motor to sun gear adapter into place.  This one is fairly tight, you might need to chamfer the corners to it inserts slightly easier, potential revision for later.  Sit the cap on the ring gear.  Attach the motor housing cap from underneath using (6) M4x16 this will make the ring gear, motor cap, and motor housing one piece.

Wire up the electrical bits as shown. It's all pretty easy stuff positive to positive and wot not. Add a dab of hot glue to keep the jack well secured, dab on the switch for good measure. And the complicated bits are assembled. Attach to the motor housing with M4x16s.

Put the M4 heat set inserts into the grinder clamp. 

Insert the coffee grinder into the planetary-to-coffee grinder adapter. Attach the planetary assembly to the base using M4x16. Insert the planetary to coffee adapter into the planetary assembly, because the mounting has a pentagonal inset it only goes in one way. Then apply a piece of masking tape to the coffee grinder(the tape is effectively a shim anything thin should work), then attach the clamp to the grinder body with m4x12 screws. 

Plug it in and get to grinding I suppose.