How to Use a Dial Caliper

Hey everyone, it’s Nick here at Higher Precision and today we’re going to be talking about how to read a dial caliper.

A dial caliper is one of the most commonly used precision measurement tools in the manufacturing industry today. With me I have a Fowler 0-4″ dial caliper. 6″ and 12″ dial calipers are probably the most common but some manufacturers do make these gauges up to 24 inches in length.

Before we do start measuring, the first thing you want to do is to clean the measuring faces. With a soft cloth, you want to quickly wipe down the ID and OD jaws to ensure that they are free of dust, coolant, and dirt. Once the ID and OD jaws are wiped down we’re almost ready to start measuring but first let’s take a closer look at the different parts of a caliper. So the different parts of a dial caliper: first we have the OD jaws for outside measurement, the step measurement, ID jaws for inside measurement, the bezel, the carriage locking screw, the depth rod, as well as the thumb wheel.

Now before we start measuring the first thing we need to do is a zero point confirmation. To achieve that, we’re going to shut the jaws on the caliper and make sure that the needle is pointing to zero. If for any reason the needle is not pointing to zero when the jaws are shut, the operator can easily rotate the bezel on the dial until the needle is pointing to zero with the jaws shut. Once you’ve achieved the zero point confirmation, the gauge is ready to start taking measurements.

Now that we have gone over the different parts of the dial caliper as well as the zero point confirmation, we’re ready to start taking measurements. So as you can see on the dial caliper here does have a main graduated beam that is clearly broken up into one inch increments and the one inch increments are also broken up within a tenth of an inch. So the first part of our measurement will be read directly off the main graduated beam and the second and third decimal point will be read directly off the dial.

So let’s try taking an OD measurement to start here. I put down this setting ring and I’m going to take an OD measurement on it. I’m going to have the measuring faces come in on outside part of the workpiece here. I can see that I am clearly past the one-inch mark. I’m clearly past the 2-inch mark. I’m not quite at the three inch mark there but I am past the .900 nches so I know the beginning part of this measurement will be 2.9 something-something inches and to complete the measurement I’m going to take a look at the dial. I can see the dial is pointing to “08” which would make the complete measurement 2.908 inches or 2 inches 908 thou.

The same principles can be applied for an ID measurement with the inside jaws. To achieve this I’ll flip the setting ring up on its side insert the inside jaws into the workpiece and open them up all the way. I can see that I’m past the 1 inch mark I’m not quite at the 2 inch mark but I am past the point 6 inches so the beginning part of my measurement will be 1 point 6 something-something inches. Taking a look at the dial I can see the dial is pointing to 0 for a complete measurement of 1.600 inches or one inch 600 thou. We’re right on the money as we’re looking at a 1.600 inch setting ring. Well that wraps up how do you use a dial caliper. I would recommend to grab a set of gauge blocks with your dial caliper and get out and spend some time practicing to make sure that you are reading your gauge correctly. If you do have further questions feel free to reach out to us at Higher Precision .com and until next time we’ll see you again.