Bricia Lopez, in "Oaxaca: Home Cooking from the Heart of Mexico" recommends an Indian wet grinder for grinding nixtamal into masa. One grinds for 40 minutes, scraping down as needed, after adding 1/3 water by weight. This yields a too-wet masa that one corrects with masa harina; the masa still comes out much better than straight masa harina, even Masienda's. A wet grinder is easy to clean.

One can find much more information about this in a thread I started on my favorite food forum:

https://komodokamadoforum.com/topic/10767-nixtamal-masa-taco...

Masienda corn deserves the highest praise. I've tried other chef favorites such as Anson Mills. Their corn is remarkable for other uses, but doesn't come close for masa.

This weekend I bought prepared masa as a reference, from Primavera, a Mexican restaurant stand at the Ferry Plaza Farmer's Market in San Francisco. Most commercial masa found in California is generic and inferior to what one makes from Oaxacan corn from Masienda. Primavera makes their own nixtamal from their own corn sources, with exactly my aspirations, and there's an argument they serve the best Mexican food in the Bay Area.

Their masa was smoother than I get from the Indian wet grinder, but this had no impact on making tortillas. (Most general purpose home tools such as meat grinders or food processors yield masa that is too course for tortillas.)

Their masa was not as flavorful. It serves their purposes well, as they use it for everything, and it needs to be a neutral foil to many kinds of food. Masienda corn almost requires pairing like wine; every corn is different.