Micrometers help you measure with extreme accuracy
If you're working on a piece of machinery and need to make a repair or adjustment, you'll likely need a micrometer. A micrometer is a lot like a caliper but more precise. Shaped like a C-clamp, a micrometer can measure down to 0.0001 inch. For reference, a human hair is 0.004 inch thick. Comprised of two measuring rods and a movable jaw, you can use them to find any dimension. To get those numbers, you use a thimble and friction screw or barrel.
When you use the micrometer, you'll put the object you're measuring between the two rods. Then you'll have to turn a friction screw or barrel so that the rods close in around the object. Here's the tricky part. Do not over screw! You only want the rods to touch the object lightly. It may look like a C-clamp, but you don't want to use it like a clamp. It's all too easy to deform or damage the object and/or the rods if you over tighten. Once you have turned the friction screw or barrel the correct amount, you need to flip the locking lever. That will hold everything in place so you can read the measurement.
As you the turned the screw or barrel, you noticed that some numbers on the sleeve were covered up or revealed. You'll get the measurement from the sleeve and thimble. Here's a super simple trick to learn how to read a micrometer. If there are four lines between each number, think of each line on the sleeve as 25 cents. On the left is a zero. So if after turning the screw you are five marks to the right of the zero, you have how much money? $1.25, right? In micrometer terms, that would actually be jotted down as 0.125. Next look at the markings on the thimble. Think of each mark on the thimble as 1 penny. If the thimble marking is at 12, then you add 12 pennies to $1.25 cents and get $1.37, or 0.137 in a micrometer measurement. If there are five lines between numbers, then you'd use 20 cents and so on.
Take care of the micrometer to make sure that you always get accurate readings. After each use, clean the contact surfaces. With such delicate equipment, just a bit of dust can make a big difference in a reading. One way to clean the surface is close the micrometer in on a piece soft paper. Lint left behind? Use a quick breath to remove it. Never use compressed air on a micrometer or any precision tool; any force can damage it. We have other tools to help you make a variety of measurements, too: laser levels, contractor calculators and measuring tool accessories. If you need it, Sears has it.