The SG-1

A good mortar and pestal will probably work better, leaves your grindings in a nice easy to scoop from/clean bowl and will give more control over fineness of grind. But if you really want to go manual just get a standard hand cranked old fashioned grinder they are still made and common on the used market, been using the same $5 Trosser grinder I got from an antique store 20 years ago, 50 years old when I got it and still works great, does everything from flour fine to just cracking the beans.