We are watching as steam locomotive specialist Jason machines a 2-8-0's main driver so that it is no longer out of round. Notice the shiny upper part of the rim; this signifies that about half has been properly finished. When in use on the locomotive itself, that main pin will be subjected to thousands of pounds of thrust. This type of work I find completely amazing. Here is a piece of cast steel, weighing hundreds of pounds, being shaped to the tolerances of a few thousandths of an inch by a huge machine and a tiny carbide tip. I feel so privileged as a steam fan for finally witnessing such precise machining with my own eyes. A close-up HERE.
