15:1 Low Profile Cycloidal Drive Gearbox for NEMA 17

This is my 2nd cycloidal drive, which has a few more non-printed parts but in exchange is much more robust and reliable long term. It is optimized for having minimal parts for ease of assembly and maximum reliability. This drive also has, in my opinion, a much better assembly guide.

All parts are designed with partially bridged counterbore holes to be printed without supports, the prearranged parts file has all of the parts in the correct orientation.

Basically any filament should be fine for printing the parts.

The clearances are a bit loose by default to try and make it work efficiently without modification on as many printers as possible, but if you want to try and tune the clearances for your printer to get lower backlash, the individual CAD files are available for easy modification. 

Hardware needed: 

3x M4x8mm heat set inserts (shorter is fine)

4x M3x5mm screws

4x M4x18mm screws (a bit longer or shorter is fine)

6x M4x16mm steel dowels (a bit longer or shorter is fine, but it must be =>12mm and <=18mm)

Assembly Instructions: 

Step 1 (Heat Set Inserts): 

First, grab the output plate piece and insert the flanged ends of the heat-set inserts to the holes on the plate as shown in the image below. 

Next, use a soldering iron with a heat-set insert tip to insert the heat-set inserts. 

After you finish, the plate should look like this: 

Step 2 (Assembly): 

First, place the housing onto the NEMA 17 motor and secure it on using the 4 M3x5mm screws as shown below. 

Then, insert the eccentric1 piece onto the motor shaft, and place one of the cycloidal disks onto the eccentric piece as shown. Now you can also optionally apply lubricant to the lobes of the disk and the eccentric piece. 

Now, place the eccentric2 piece onto the shaft. It should look like it is offset 180 degrees from the eccentric1 piece. Next, place the 2nd cycloidal disk onto the eccentric2 piece. It is critical that you align the 2nd cycloidal disk correctly with the 1st disk, otherwise the output pins will not fit into the 2 disks correctly. The first and second disk holes should overlap enough for the output pins to fit through all of them. Ensure your disks look like the 1st picture and not the 2nd. You can also add lubricant to the lobes of the 2nd disk and the 2nd eccentric piece now if you wish. 

Now, add the 6 M4x16mm steel pins to the output piece as shown:

Insert the output piece with the pins into the 2 disks. The output plate should lie on top of the 2nd disk as shown, if the pins struggle to fit in check the alignment of the 2nd disk with the 1st. 

Place the output holder onto the drive and screw it in with 4 M4x18mm screws. 

That's it, you're good to go now!