The crank is put through a process called carburization (sp), which diffuses carbon molecules into the steel at high temps for greater hardness of the steel. The problem is if you shave past this then the crank will be "soft" and you'll have bearing problems, not to mention you might not be able to run Honda bearings. This process costs alot so when weighing the costs it is always better to just buy another crank that is good to begin with.