Check out these milling machine components images:
Evolution
Image by Bushman.K
Two buttons produced in distinct times with slightly various logos. Produced by Allen-Bradley (presently, part of Rockwell Automation). Logo on the left still has decorative element – curved line with underscore, that goes from horizontal dash in "A", like in original 1924 logo. Stop button appears more modern day, but letters nevertheless have serifs, although later logo, employed prior to acquisition by Rockwell, functions sans-serif font.
Grinding mill, 1637
Image by Marcel Douwe Dekker
Supply: Song Yingxing (1637) Tiangong Kaiwu, part three on agriculture and milling processes