This is a guide on how to create a Coffee Grinder using3d printed parts, a steel conical burr, and a high-torque motor.
This guide assumes that you are using parts that are rated for foodsafe applications.
Step 1: Gather Your Parts
Step 2: Insert the Bearings
Insert the two bearings into the 3d printed part named "bottom.stl"
Step 3: Insert the Conical Burr
- Take the axle that comes from the gearbox kit, and thread it into the cone burr.
- Add the white plastic piece that comes from the gearbox kit to the assembly, making sure the plastic tabs fit into the metal holes, and the piece seats properly.
- Insert the conical burr/axle into the piece from the previous step
Step 4: Insert the Shaft Coupler
Add the printed part named shaft_coupler_top.stl to the assembly as shown, making sure to face the rounded corners up and into the part.
Then add the internal tooth lock washer that came with the gearbox kit.
Then add and screw on the nut that came with the gearbox kit.
Step 5: Attach the Ring Burr to the Top
You will need to remove the white plastic the ring burr comes with in order to perform this step.
Insert the ring burr into the top as shown, making sure to align the flats of the ring burr with the nubs in the printed part.
Turn the ring burr 90 degrees inside the printed part.
Insert the worm/grub screws into the holes on the sides to lock the ring burr in the part.
Step 6: Prepare the Motor Adapter
Using template.stl, assemble and drill as shown.
I recommend using a drill press and to center punch the holes to keep the drill from wandering.
Step 7: Assemble Motor
- Add the motor adapter you just prepared to the motor shaft.
- Add the 5/16" SAE washer
- Add the m6 nut and tighten until the motor turns a little bit.
- Add the shaft_coupler_bottom.stl
- Add m3 washers and bolts
- Attach to bottom with either m3 lock nuts or with lock washers and nuts.
Step 8: Attach Bottom to Motor
Put the bottom assembly on to the motor assembly.
If the bottom assembly does not seat all the way, you will need to rotate the conical burr to make sure the shaft couplers engage.
The bottom of the bottom assembly should touch the top of the motor assembly.
Step 9: Optional: Add Feet
Glue the feet on to the bottom of the motor.
The grinder can get pretty noisy, and it's a good idea to use vibration dampening feet like the sorbothane feet seen here.
Step 10: Final Assembly
Screw on the adjuster (shown in blue) to the top piece (shown in yellow) as shown, taking care to line up the adjusters tabs with the nubs on the top piece.
Insert the top assembly into the bottom assembly so that it is seated fully.
Rotate the adjuster to adjust the grind.