Dial calipers, digital calipers, and digital micrometers are used to measure the dimensional characteristics of all metals. This article will discuss how to use calipers for measuring metal rod, sheet and plate, how to read calipers, and explain the differences and uses of each.
Dial calipers are used for measuring diameters, thicknesses, and lengths of small items. To measure an object, open the dial caliper to fit around its sides, and then close down the caliper until it touches both sides. Reading the caliper scale at 7 and the round dial at 56 means that the object is 756/1000 inches in width or diameter.
Digital calipers are used for measuring diameters, thicknesses, and lengths up to six inches. The readout is in inches and thousandths of an inch in decimals. The advantage of a digital readout is for accuracy and repeatability, because the operator is not required to interpret off of a scale. To use the digital calipers, turn them on, make sure it is zeroed out, and then open the calipers to fit around the object. Hold the wheel firmly to tighten both jaws of the caliper against the metal, and read out the measurement on the digital display.
The 0-1” digital micrometer is used to measure diameters or thicknesses up to one inch in diameter, with an accuracy of 0.0001”. To use it, open the micrometer to greater than the thickness to be measured, place the anvils on both sides of the object, and then tighten the spindle to so that the anvils touch both sides of the object. The thickness can be read from the display in thousandths of an inch.
At Industrial Metal Supply, the frequency of inspection for calibration of calipers and micrometers is annual. Visit www.industrialmetalsupply.com for all your metal and metalworking needs.