As you may know, some coffees from the Middle-East / Mediterranean have cardamom ground into the coffee, which is super-fine and prepared in a copper/metal pot.
Is it safe for me to experiment with whole cardamom pods put inside hand-grinders like the Kingrinder K6?
Would it clog up the grinder because these pods contain more moisture and fibrous material?
Plenty of people say they grind spices in a coffee grinder without issue. A coffee site writer even says they grind parmesan - wild. If you do, you might consider putting some rice through the grinder afterward, to pull out some of the oils and residue.
That said, I wouldn’t recommend it with any reasonably expensive grinder - like the one you named. It feels like using a race car to tow a trailer - it may work, but it’s just not the tool for the job. And from a quality stance, the best grind size for the cardamom is likely different from the coffee.
The right tool is a molcajete or a mortar and pestle. They’re fast, affordable, easy to clean, don’t risk cross contamination, and allow easy experimenting with grind size.
(Edit: Will update with sources when able)
I think it should be ok to put cardamom pods inside the coffee grinder. I don't have a hand grinder but I've done it successfully with electric blade grinders.
The burrs in my Ascaso burr grinder are carbide, hard enough to chew nails. Really. Carbide is used to machine hardened tool steel. I run cinnamon sticks through the Ascaso as well as coffee beans.
I can't think of any biological material that would match carbide for hardness, even tooth enamel. Diamond has a hardness rating of 10 on the Mohs scale, carbide 9.5
