This is a funnel device for attaching to a multi-stage hand grinder. It allows you to easily regulate, and control the direction of flow of material out of the grinder. This particular design was made with the Sharpstone 2.2" herb grinder in mind: http://www.sharpstonegrinders.com/sharpstone-clear-top-4-piece-grinder-2-2-silver/

I have had some success scaling it to fit grinders of slightly different brand/size. Let me know if you are able to make it work for other grinders.

If you have the same size grinder as me then you don't need any scaling and should be able to print directly and start with step 1. If it is a different size scale it using 53.3mm as the base size of mine.

1. Print out the piece. I like the ABS ones I've printed more but the PLA ones work fine too.
2. I print mine with a raft, so the next step is to remove the raft. I use a Dremel.
3. Depending on how good your printer is at doing overhangs/bridges, the thread ring may be a little wonky. If it is just take a Dremel or other rotary sanding device to it to even things out.
4. Test for fit on your grinder and make any necessary changes.
5. Enjoy improved control on your hand grinder.