Me ha parecido interesante y ahi lo dejo por si alguien dispone de media hora libre
"This thing is amazing! It is a Foley Automatic Filer Model 61 from 1954-1958 made by the Foley Manufacturing Co. of Minneapolis, MN. It has the capability to sharpen and joint hand saws, band saws, and circular saws. These sold for around $250 USD in 1954, which is equivalent to $2300 USD in 2019. They were marketed as the all-in-one sharpening solution for running your own sharpening business. "