Does You Machining Work Require Close Tolerances? Here are a Few Facts You Need to Know. Posted on December 29, 2013Author Shares PostPosted in Business Does You Machining Work Require Close Tolerances? Here are a Few Facts You Need to Know. Reference links. Helpful info also found here. Keywords: Precision cutting tools, Precision cutting tools, Cat 40 tool holders, Threaded shanks, End mills for aluminum, Aluminum cutters.