Calipers, calipers, calipers. This simple little tool comes in more varieties than you might think. There are many different types of calipers available depending on the precision measurement job you are trying to accomplish. Today we are going to give you a tour of the various caliper types. We hope that this will increase your level of expertise in precision measurement tools and help you prepare for your next precision measurement task.
In general, calipers are tools used to measure the distance between two spots on a part or object. The caliper is adjustable to be placed with its tips, or jaws, on the two corresponding points of measurement, and the distance can be read from the caliper readout or by comparing the distance of the jaws against a measurement reference. Calipers are simple in concept, but undeniably useful in a number of fields like metrology, mechanical engineering, woodworking, medicine, metalworking, and science. There are 8 different types of caliper available today. These include: inside caliper, outside caliper, divider caliper, oddleg caliper, micrometer caliper, Vernier caliper, dial caliper, and digital caliper.
Inside calipers are used, as the name implies, to measure the interior of a part. When using an inside caliper, the jaws are placed in the interior walls or areas of the part being measured and adjusted so that they are snug, but not causing damage. Oppositely, outside calipers are used to measure the exterior of a part. The jaws are placed along the outside surface for measurement, and these calipers have a great capacity to measure very large outside distances. A divider caliper may more commonly be known as a compass. The points on each jaw of a divider caliper are sharpened in order to act as scribes to mark out particular locations on a part. These are often used to measure distances on maps or blueprints. Outside calipers are sometimes call oddleg jennys or hermaphrodite calipers and are used mainly to mark out a particular spot a certain distance from one side of a part. A bent leg rests along the edge of a work piece while a straight leg’s scribe marks the required location. The micrometer caliper is very simply a micrometer. Micrometer caliper is just the full name for the tool.
Vernier, dial, and digital calipers are all very similar in build and function, but vary mainly in the way in which the final measurement readout is displayed. Each of these calipers provides a direct measurement reading as opposed to the calipers listed above which require comparison against another measurement reference. The standard Vernier, dial, or digital caliper comes with jaws for inside or outside measurements, as well as a depth probe for conducting measurements of depth. The Vernier caliper is set apart because of its Vernier scale. A Vernier scale is a visual scale with different gradation marks that allows for very accurate interpolation. Reading a Vernier scale requires practice and skill. Dial calipers utilizes a dial readout system, which typically may be rotated to allow for differential measurements. A digital caliper is a more modern version of the dial caliper and provides a measurement readout on a display screen that is digitally calculated. A major benefit of the digital caliper is that it can sometimes be connected to a computer for data collection and storage.
Calipers are handy little tools that allow for reliable and precise measurement of distances along a part or object. They come in a range of designs. Depending on the complexity of your needs, you might want just a simple one-purpose caliper, like an outside caliper. Alternatively, you might want a more all-in-one tool and choose a Vernier caliper. The choice is up to you, and there are plenty of caliper types to suit your precision measurement needs.