Selecting a Digital Caliper on Amazon.com
A digital caliper, also known as an electronic caliper, has a digital readout that displays measurements of inside dimensions, outside dimensions, and hole depth. It is a type of slide caliper with a pair of jaws attached to a beam that has a marked scale; one jaw moves along the beam to fit around the object being measured. Most digital calipers also have a depth rod that extends from the beam to measure holes. The jaw movement is electronically sensed and displayed on an LCD. Readings are shown in either inch or metric values, and many digital calipers can be switched between these units of measure. Commonly used in metalworking, mechanical engineering, machining, carpentry, and medicine, a digital caliper is particularly suited for quality control in production settings where specific diametrical or thickness measurements must be repeated frequently with precision and accuracy.
Among the features a digital caliper may offer are data hold for locking in values and relative zero for taking differential measurements. When selecting a digital caliper, the maximum measuring speed (also known as the maximum velocity or speed of displacement, slider speed, or tracking speed) is a consideration. This capability refers to how quickly the caliper can track jaw movements to register a reading, and is usually measured in inches or meters per second. The resolution and accuracy of digital calipers varies from tool to tool. Some digital calipers have an output for connecting to a computer or printer via a USB cable, an RS-232 cable, or a wireless connection to capture and record data.
Digital calipers vary in their maximum measurement capability, with 6", 8", and 12" lengths being common. Where an extended range is required, a Fowler digital caliper is available with a maximum measurement of 40". Many digital calipers have a battery-powered readout, though the Mitutoyo digital caliper Absolute series offers a number of solar-powered models. When measurements must be made in wet or dusty environments, a digital caliper that has an Ingress Protection rating may be selected.