The Valley Woodworker: The Keystone Railroad tool grinder
The Keystone. The smaller Hoppe. The Keystone has a much thicker work surface capacity. Shown installed on a 2X4 top, roughly 1-1/2 in thick. The smaller Hoppe had to be mounted on a thinner board, nominal 3/4 in this pic. The small Hoppe has a pinkish wheel, which has acquired a rounded profile on its face.