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INTRODUCTION

There are many reference books on the market today, starting with Machinery’s Handbook, that provide much of the technical and reference information a machinist or engineer may ever need. It is still not easy, however, to find a book that provides practical “how to” information that can immediately be put to use to improve one’s machining skills, craftsmanship, and productivity.

The purpose of this book is to fill that void and provide concrete suggestions that can help you think and produce like an experience machinist. If that’s what you’re looking for, you’ve hit the mother lode.

This book is directed primarily toward the conventional tool room machinist working in a small shop environment. Many CNC machining suggestions are also included. By virtue of pricing and delivery competition, most small shops have to be very good at what they do. You will find that the equipment and techniques referred to in these pages are commonly seen and used in small machine shops.

Tool room machinists are the ones called upon to do prototype and low production machining. They may also be called upon to build and maintain tools such as dies, molds, and fixtures, and occasionally sweep the floor. An accomplished machinist should possess many of the skills of a mechanic, craftsman, and problem solver.

Practitioners of the trade are likely to stay quite busy as they face the daily challenges of getting things done. The trade is well suited for results-oriented people.

If you’re the type of person who frustrates easily, then you’d better stay away. If you enjoy a challenge, are mechanically inclined, and have an eye for detail, then there are a lot of good reasons to be in the trade. The following list highlights the reasons I like the trade and have stayed with it for so many years.

•You get to destroy as you create. After nearly forty years working in the trade, I still like making a big mess of chips.

•It is “real” work and you get to produce solid, tangible products you can see and feel.

•There are many different areas of the trade you can go into, depending on your preference. Some of the options are: mold making, die making, jig and fixture making, general machining, CNC machining and programming, or in some cases you may get to do all of the above. The techniques used in each of these various aspects of the trade overlap nicely and contribute to your pool of knowledge and experience that can be carried over from one job to the next.

•You’re in control. Once you become proficient at machining and producing good parts, people will usually leave you alone.

•You get a chance to use your brain once in a while. The work is not all mundane. You’ll have plenty of opportunity to use your brain, not only to solve shop math problems, but also to solve setup and planning problems. You’ll come to appreciate to some extent the schooling you suffered through as a kid.

•The job is somewhat physical, but not so much that you will be exhausted at the end of the day. In most cases, you get to move around quite a bit. For my money, it beats sitting behind a desk.

•Jobs are available and abundant. Machinists are needed in every industrialized area of the world. If you don’t like where you’re working, then you can usually find another job without much difficulty.

•Machining is something you can do even as you get older. You won’t see many seventy-year-old carpet layers, but you’ll see plenty of seventy-year-old machinists and toolmakers still working.

•The “fringe” benefits are nice. I’ve used company equipment to make hundreds of personal projects.

•The work is relatively safe. You don’t hear about many machinists being mortally wounded on the job.

•You don’t have to spend a lot of time dressing up and grooming for the job.

•The machines do a lot of the work for you. Once a cut is going, you can relax to some extent.

•You won’t have to spend a lot of money to learn to be a machinist. You will, however, need to spend money for tools.

For the many positives this trade has to offer, there are also a few negatives. The following are things I don’t like about this trade.

•Because you are producing solid, tangible parts, it is easy for others to follow your progress and criticize what you’re doing.

•The better you are, the more work you’ll get. If you are accurate and efficient, youll end up getting a lot of “hot” jobs and, believe me, there will be many of them.

•It can be difficult to erase mistakes. For example, a draftsman or engineer can hit a “delete” button or use an eraser to quickly wipe out a mistake, and then proceed from that point. If machinists drill a hole in the wrong place or cut a diameter too small, they may have to start over. There is no “delete” button for machinists. This can be costly, both financially and psychologically, depending on how many parts were made wrong, how much time was spent on each part, and how the critics react.

•Machining is very tool intensive and you can’t work efficiently without them. You are constantly looking for, changing, sharpening, buying, making, or borrowing tools. Sometimes I’m envious of the computer people who have all their tools right there on the computer screen, just a few clicks away.

•For some reason, machinists are often treated like second-class citizens. One example is air conditioning. You will often find in a company air conditioning everywhere except the machine shop.

I could list more but, all in all, I believe the positives outweigh the negatives by quite a large margin.

I suspect many trades and professions have rules, methods, and ideas that get passed along from one generation to the next. In this book, I’ll attempt to identify and correct some of the misinformation in our trade. One “myth” that comes to mind is that “You should never turn off a surface grinder once the wheel is dressed.” The fact is: you can turn the wheel on and off as much as you like without dressing the wheel, as long as the wheel is mounted tightly enough so that it doesn’t move or shift on the spindle.

No matter how hard we try to avoid making extra work for ourselves, things go wrong. Taps break, cutters break, materials warp, indicators lie, digital readouts skip, milling heads move, vise handles jam, and mikes and drawing are misread. Parts fall on the floor, disappear, or get made out of the wrong material. It’s Murphy, of course (from Murphy’s Law). I’ve spent the better part of my life trying to get one over on that guy. It’s not easy, but I’ve nailed him many thousands of times now, and it’s always very satisfying.

I’ll show you ways of sharpening taps and cutters so they won’t break, and how to remove taps, screws, and cutters that have broken. I’ll show you ways to close down oversize holes, minimize material warpage, repair threads, and plan jobs to avoid trouble.

Most of the suggestions I’ve made in this book are techniques and rules of thumb that work for me. It doesn’t mean they’ll work for you or that you’ll even agree with them. I’m always looking for better and easier ways to do things. I’m always experimenting and streamlining techniques that work for me. I suggest you do the same.

To present these suggestions in a concise, easy-to-read format, I’ve chosen simply to list them.

Some of these rules and suggestions are presented as statements; others are presented as questions followed by answers. Some of these rules stand alone, and some are followed by more complete explanations.

For those readers who already know everything, I’ve included a chapter especially for you. It’s called “Tell me something I don’t know.” In this chapter, I’ll present some little known, little understood, and in some cases not very useful information about metalworking. For example, how many of you out there know how to make a Slinky®? I mean a real Slinky, not just a curly chip. In this chapter, I’ll tell you.

In the back of the book, I’ve included an appendix with drawing of tools that I frequently use in the shop.

New to the Second Edition

Several improvements have been made to the second edition of Machine Shop Trade Secrets, including:

•Full-color design and photos. The first edition was a one-color book; here we’ve gone to full-color. The photo images are sharper and clearer because they’re in full color.

•Improved layout. The book has been redesigned so that most topics are self-contained on a page. Even more important, figures and the accompanying text are now almost always on the same page, making it easier for you to follow them.

•Tables and featured boxes have been added. These features highlight the information that might otherwise get lost in text.

•Chapter 15 on Computer Numerical Control has been thoroughly revised and updated. A lot more focus in this chapter has been placed on computer-aided design, manufacturing, programming, and CNC machines.

•Summary tables appear at the end of most chapters. These tables provide you the opportunity to easily review the suggestions within that chapter, whether to help you find specific suggestion as you approach the chapter, or to review after reading the chapter.

•The end-of-book index has been thoroughly revised and increased considerably in size and detail.

It’s been said that “metal is man’s servant.” I’ve spent many years pursing that goal — so let’s get started sharing what I’ve learned!

James Harvey Garden Grove, CA