69 - Bench Top Storage System, страница 34
TOOL CHEST Body features scales in millimeters and inches. Small jaws used to take inside measurements Dial displays decimal (0.01") and fractional (1/m") measurements. (One rotation equals 1".) Large jaws used to take . outside measurements General Dial Caliper Bezel can be rotated to "zero out" the dial of the caliper Knurled thumbscrew provides gear-driven movement of caliper head Back of caliper features fractional equivalents for Vu" dial readings plastic dial caliper made by General (you can see it above). I use this caliper just about every day in my shop. You might be asking yourself what makes the General so different? One simple reason — the measuring scale on the dial. Dial Readings - If you look closely at the dial, you can see two separate sets of markings. The first set (green ring) is graduated in hundredths of an inch (0.01"). I know, that's sdll not woodworker friendly. But just inside that is a second ring with graduations in Via" increments. If you look at the jaws above that are measuring the width of the tide of this article, it's easy to read the measurement — 228/m". Not good at reducing fractions? Simply flip the caliper over and check the handy chart on the back to "convert" the measurement to 27/i6n (see inset photo at upper right). Making an "outside" measurement like this is what I use my dial caliper for most often. As a matter of fact, my dial caliper is a constant companion when I'm working at my planer. I use it to double-check the thickness of a freshly planed work-piece, as in photo A. Plus, a dial caliper works great for checking the size of router bits and drill bits — especially the small ones that don't have the size stamped on them. Inside - In a similar manner, you can use the smaller jaws on the opposite side of the dial caliper. As you can see, the measuring edges face outward. This makes it easy to measure material that's "missing," like the width of a dado or groove, as shown in photo B. Step Measurements - I often need to make a measurement where I don't have two "sides" to rest the jaw against, like the width or depth of a rabbet. Making this "step" measurement is easy because of the unique design of the jaws. The smaller rear jaw on the inside of the dial caliper can be set against the edge of the rabbet, like you see in photo C. Then slide the head of the caliper against the inside step to make the measurement. Depth Measurements - One last thing. Measuring the depth of small openings can be a real challenge — but not with the General. As you extend the head of the caliper, a slender rod projects out from die opposite end. This rod makes it easy to measure the depth in places the jaws won't fit, like the mortise shown in photo D. Cost - My General dial caliper (Model No. 142) cost around $27 — a small price to pay for taking accurate measurements in a variety of ways. For me it's the key to building a great project. To order a General dial caliper, check the sources listed in the margin on the opposite page. Improve your woodworking with an inexpensive dial caliper. I've owned an expensive, metal dial caliper for years. Unfortunately, it sits in a drawer in the box it came in and doesn't tend to get a lot of use. The problem is it reads in thousandths of an inch (0.001"). Sure, it's accurate. But it's not a very useful measuring scale for woodworking where you're always dealing with fractions — and having to convert the measurement in thousandths to a fraction is a hassle. But that all changed a few years ago when I ran across an inexpensive 34 ShopNotes No. 69 |
