Machine Shop Trade Secrets. James Harvey
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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
As machinists, how often are we asked to produce hardware that was needed “yesterday?” The answer is “quite often” because shop personnel try to keep squeaky wheels greased. Squeaky wheels come at us from all sides, including:
•Production workers count on machinists to keep lines going.
•Research and development employees count on machinists to keep new product programs on track.
•Maintenance specialists count on machinists for repair parts.
The bottom line is this: when people want parts, they want parts. They don’t want excuses or anything else. That’s one of the beauties of being a machinist. Your responsibilities are clear and simple. If you can get people their blessed parts, they’ll go away.
Most people, including myself, don’t want to work any harder or faster than necessary. At times, though, when the crisis monkey is on us, we have to get the lead out and get going. Crisis machining can actually be fun once in a while. Generally speaking, any glory to be had usually comes from helping someone through a crisis. If nothing else, it can be a nice change of pace. The hours tend to go by quickly when you’re working on a “hot” job.
1.Turn man-time into machine time.
This philosophy is popular for saving time. It goes with the idea that you should never hold back on technology. From a business standpoint, the philosophy makes sense. You can also turn man-time into machine time with thoughtful planning. This is easier said than done. The fast paced environment many of us work in today often doesn’t allow for proper planing.
2.Have lots of tools.
An easy ways to improve speed is to have lots of tools. I like to have and use my own tools—even if the shop is well stocked. Shop tools are never put back in exactly the same place and you’ll never know what condition they’ll be in when you find them.
If you’re just starting out in the trade, I recommend buying a set of tools from a retired machinist. This way, you’ll hit the ground running and you’ll immediately be worth more to your company. Machinist’s tools hold their value well, so be prepared to pay a fair price. You can upgrade later as you see fit.
Avoid borrowing tools over and over. If you use a tool often enough, then either buy one or make one!
Don’t waste your time making easily purchased tools like 1-2-3 blocks and V-blocks. Instead, make custom tools and fixtures that aren’t easily purchased; you can tailor these tools to the machines you use and the type of work you do.
3.Use dedicated tools.
This business of having one tool that does everything isn’t very efficient. You often see these kinds of tools advertised in the back of the mechanic’s magazines or on television infomercials. For the most part, each tool you have—whether it is a hand tool or a power tool—should serve just one purpose. You want the tool to be ready when you need it.
I suppose you could get carried away with this type of thinking. I wouldn’t go so far as to buy a handle