This grindstone machine has a foot pedals to control the speed of the stone to sharpen metal to the point of perfection. Coloma California gindstone,sutters mill. Read More. Antique Sit And Pedal Treadle Gridstone. For sale is a Vintage Grinding stone wheel for sharping tools and axs. It works well and has a old metal seat and you pedal it like a bike to turn. Frame is in good ...