Users of tools seldom know or understand how or why a tool is designed a certain way. They are so concerned with the result of the work, that they don't consider the process itself. In this primer all of the American makers of gunsmithing reamers, gauges and other tools have come together to answer the questions that every gunsmith should know the answer to. Understanding tools will increase your efficiency and the quality of your work. Making you more money and making clients happy with the end product. Damaging tools or guns because of the lack of some basic knowledge is wasteful as well as unnecessary. Consider this the FAQ (Frequently Asked Question) book for tools and thier correct use. Professionals are seldom taught this information in school. In stead they opperate on wives tales and mysteries that one guy shares with the next. Hobby gunsmiths have it even worse as they seldom receive any formal training at all. These tools are not black magic. They are fabricated with tried and true design principals. If this subject interests you, the benefits of this information will make your life much easier. Tools life, will be better, saving you lots of money over time. Instead of taking a lifetime to pick this information up, one tid-bit at a time, read this primer and jumpstart your knowledge base by many years.