Thread cutting nuts or Palnuts: https://www.huyett.com/all-products...ading-nuts/self-threading-palnut-stamped-nuts
Auveco is a stones throw from my home . No counter sales available . The parts house I buy from is a distributor for Auveco , it takes 3-4 weeks to fill the order . Auveco = Auto Vehicle Parts Company
Palnut Capped Washer Type Lock Nut is the official name...but you can probably find them using some other terms mentioned above
How many do you need? I used to get them a few at a time at our local auto parts stores, I found them on Ebay, or Amazon in larger quantities a few years back.