Sourcing snap button rivot system -- 2

Looking for an 8mmx8mm square brass(or other hard metal, non-plastic) snap button rivot system. Will need the press machine or "dye". The dye does not need to be an automatic machine and would be preferred to be a hand tool as shown in attached pictures. The square snap can have slightly rounded edges like the one in the pictures or it can have sharp pointed edges(preferred).