The holes in the pinion gears of Climax locomotive CN 1551 are in need of being
bored to make the holes straight and true, to allow us to make the gear shafts
that they are to be mounted upon may fit properly. Why are the holes in such bad
condition, taper-wise? Several factors may apply: 1) age of machine upon which
it/ they were machined (totally worn, crapped-out lathe or boring mill), 2)
quality of cutting tools used in their machining (carbon steel or high-speed
tool steel, definitely not carbides) 3) quality of castings (Hard inclusions,
such as foundry sand or slag, imbedded in the casting that will dull cutting
tools and thusly cause diameter changes). The oval condition may have been
caused by the installation of a key that was way too tall for the available
keyway dimensions, and the gear was forced out-of-round as it cooled during the
sweating-on process.
