Rancilio Rocky Stepless mod

After trying to implement some mods that I found on Reddit and forums, and not being satisfied, I decided to develop my version using gears.

Printed with 0.2 mm height, in PLA, 5 walls, 100% infill (I think you can reduce the infill, but I didn't test).

* Fixing_4 was the wrong version, with only 2 holes. I uploaded the Fixing_5 with three holes now and a new 3mf file with the correct component. Apologies for any inconvenience and thanks @MustafaOzbak_3514055 for flagging the mistake on my YouTube video.

Assembling video:

Assembling instructions:

1 - First, fix the small gear to the support (that was named as "fixing") using a screw M4 x 15mm. This one shall be tight because it will hold the burrs in position. 

2 - To install, after removing the hopper, you need to remove the button that holds the burr in position, as well as the pin and spring.

3 - Then, you need to remove a screw in order to fix the support to the grinder (it is aligned to the other hole of this support). Use the same screw to fix this support, it's a M4 x 12 mm.

4 - Install the knob (you can print with text by changing manually the filament in the last two layers or use the version without text) with a screw M3 x 20 mm, connected to the small gear. For a better finish, you can add the knob cap.

5 - Put the large gear in position.

6 - Reinstall the hopper with the original screws (I recommend to fully close the burrs and align the 3 screws so that the zero is aligned to the mark in the front).

7 - If you want, you can add the bellow, inclined base with funnel and anti-popcorn for single dose, and also the open shute.

Despite the video from  jkim_akes (https://www.thingiverse.com/thing:4768923), the retention was much higher because the new coffee was pushing the old coffee, giving the impression that it was a low retention. I measured and in reality, it's not 0.1-0.3 g, but maybe something around 1.5-2g, which is still very good for a cheap grinder. I just recommend spraying some water in the beans (search for RDT if you don't know this technique) to reduce the static and the mess.

For a complete modification, stepless, single dose and low retention, I recommend also these models:

Inclined base:

https://www.printables.com/model/1297436-rancilio-rocky-doserless-inclined-base-for-models

Bellow:

https://www.printables.com/model/1297460-bellow-for-rancilio-rocky

Shute: https://www.printables.com/model/1297474-shute-with-seal-for-rancilio-rocky-doserless