DIY grinder

#1: Post by **gania13** » January 14th, 2021, 9:28 am

Hi everyone, recently I got my first "real" coffee machine - Elektra Microcasa a Leva, and quickly started looking to upgrade my grinder (Ascaso i mini).
In this search I've encountered many interesting options, both electric and manual, and seeing all the different options left me with more questions than answers(burr type/size/taste profile/rpm/single dosing or not etc.)

Now, most likely I'll get a Niche Zero, but being a mechanical engineer, and loving to tinker with things, I've started toying with the idea of making something by myself.
I realize I'm in the beginning of research, but I'd like to hear opinions on what would be cool to make, with the potential of actually being able to produce good coffee.
The direction is probably a single doser, and I'm contemplating/questioning the following subjects:
1. Should it use conical or flat burrs?
2. What should the burr size be? (actually the idea started when I looked at the HG-1 and thought "why not buy the 83mm connical Mazzer Robur burrs and do it myself?")
3. Preferred shape for minimum retention? EK43 type or NZ type (or something else?)
4. What RPM? do I need variable RPM?
5. Where can I find the required torque to grind coffee/dedicated for a specific burr?
6. Which type of motor should I use? (Commercial grinders use AC motors, NZ uses a 240v DC motor with a gearbox, EG-1 uses brushless DC motor)

I realize these are pretty newbie questions, but I'll appreciate any input

#2: Post by **Jeff** » January 14th, 2021, 10:49 am

"Newbie" and "basic" can be entirely different things. Newbie questions tend to have obvious answers.

You have asked basic questions, one that anyone would need answered to proceed. They are also questions that mainly have no generally agreed answers.

The advice I'd give is build your own because you want a project, not a grinder.

Conicals are likely a lot easier to deal with using a home machine shop. The current "modern flat" grinders are striving for alignment and concentricity in the 10 micron range.

January 14th, 2021, 11:41 am

I'm going to be doing a grinder project soon, where I will be motorizing a Kinu M47. I want a portable grinder that I can also use at home with electricity.

From my research, most people who have built DIY grinders, do them with conical and not flat burrs. The builds just seem more straightforward, with less complex machining and grinds path with conical burrs.

I don't think variable RPM is needed with conical burrs, unless you don't get the RPM right with your initial motor and gearing setup. With conicals, if RPM is too slow, it will take forever to grind. If it is too fast, the beans popcorn more and have trouble feeding, again extending grind time. I believe the monolith conical operates at 200 RPM. The Wug-2 motor kit for the HG-1 operates up to 170 RPM. Both of those use large mazzer burrs, so around there should work fine.

January 14th, 2021, 2:45 pm

Jeff wrote: The advice I'd give is build your own because you want a project, not a grinder.

That's actually a good advice, I want a grinder, but these two don't have to be separate.
I might build something even if I get a grinder.

If I go the manual grinder route for initial experience, what is the importance of burr size? would it be only speed, or taste profile?

#5: Post by MB » January 14th, 2021, 2:47 pm

I've done two DIY grinders. Check out the latest here (and the previous one linked in the first post).

Grinder Project - Update

These both work very well. You could engineer it even more to make something really slick.