Day Two of the Guitar Program at Minnesota SE Technical College.
Day One of Tools Class had us first etching the tools with our initials, then on to lapping flat the soles of our block planes, plane iron, and chisel backs. A cutting edge occurs at the intersection of two flat, precise planes, so all of our cutting tools need to start life with perfectly flat backs and soles.
While the majority of my classmates purchased the Veritas block plane, I had the pleasure of reconditioning a Stanley 9 1/2 adjustable-mouth plane, with a Hock iron. It flattened out nicely, and will perform about as well as the modern superhero handplanes. To polish the backs of our irons and chisels, we adhered a very fine adhesive-backed sandpaper to our thick glass plates, then employed the flat, abrasive surface to annihilate all nicks and machine marks. What is left is a flat, mirrored finish.