"If it ain't broke, don't fix it," goes the hoary bromide. But what if the time comes - and it most surely will - that in fact it is broke? Do you fix it or replace it? And when does gearbox maintenance and repair arrive at a point of diminishing returns and buying new is the answer?
Highly loaded gears are usually casehardened to fulfill the high demands on
the load-carrying capacity. Several factors, such as material, heat treatment, or macro and micro geometry, can influence the load-carrying capacity. Furthermore, the residual stress condition also significantly
influences load-carrying capacity. The residual stress state results from heat treatment and can be further modified by manufacturing processes post heat treatment, e.g. grinding or shot peening.
Most of us would agree that the idea of a perfect world is absurd. Just for starters, who gets to decide what perfect means? "The Perfectionists" by Simon Winchester explores this theme as it relates to engineering.