This is modeled after the upcoming NFC disk found in this video, https://www.youtube.com/watch?v=BsxUzpH0VIw&lc=

Niche Zero is making this available to current owners for the cost of shipping and it will undoubtedly be much nicer than a 3D print. When available I'll be posting a link to the part and recommend getting it, I know I will be. For now I'm incredibly impatient and this disk is amazing and I had to have one ASAP.

I've tested it and it works just as well as the one in the video. Some small pieces, like chaff, may still popcorn out but just like in the video is significantly reduced. If the mess this can build up over time bothers you check out my hopper cap, https://www.thingiverse.com/thing:3985970. You will need to dial in your grind again. I had to go about 4 marks finer.

1/19/20
I tightened up the tolerances so the disk sits center more easily. This let me extend the walls out a bit more so less small pieces have a chance of popcorning out. This wasn't really an issue with the v1 design but it happened sometimes. I've also added a sloped walls similar to thing:4105203. After some testing I found that the sloped walls keep the beans jumping around as much.

3/12/20
Added v1.2 with a slightly larger opening similar to the official design. I've had some beans that got stuck using the smaller opening.

Also added an alternate version that is basically the same design as the official NFC disk.