in the gemara r’yosef said that grinding even with a windmill is assur.
ther is a bi machlokes b/t the rama and everyone else whether we have to be choshesh for those who interpret r’ yosef to be going even according to beis hillel.
lchoira i do not really understand what the issur would be acc. to beis hillel.if you say cuz of b’zayon shabbos then a washing machine hid away down in the basement should be mutar