When we lived in the Southwest US we saw both Indians and Mexicans in rural areas who still grind grains using a dished out stone bowl and a stone mortar. I've tried it and I'm glad that I'm able to buy mine already ground.
http://en.wikipedia.org/wiki/MetateIt certainly is hard work, but those who still use them are generally used to hard work. Like anything, when you do this often, you get real good at it.
