Using tips for digital calipers

In order to ensure accuracy for measurements, digital calipers should be checked frequently. They are easier to damage than other tools.You should calibrate the inside jaws and the outside jaws, as well as the depth rod and the step measurement. You need to clean and close the jaws for wear.Then hold them up to the light and if they're worn you'll see light shining through the gaps. If the the surfaces are unworn and you can continue to use it. However, you'll have to send the calipers for servicing for total reliability. Then the surfaces can be ground flat again.

You can use a set of ring gages to calibrate the inside jaws, but you may also set a calibrated .0001" micrometer to 1" (and higher, if possible) and then use the inside jaws to measure this distance.You'll get an accurate reading since the micrometer has a discrimination ten times that of the calipers.It's a simple matter of inserting a series of gage blocks between them and recording the caliper readings for the outside jaws. They must not deviate by more than one graduation (.001") over the first 4" of range. From 4" to 8" the error may be .0015" (one and one-half graduation) while from 8" to 12" the error can be .002". Accuracy may be different from models and the manufacturer's specs should be consulted for this information. Take readings at 1-inch intervals. Three gage blocks of 1", 2" and 3" sizes will be all you need.
Repeatability means the dial hand or digital readout returns to the same reading on different attempts to measure the same gage block. If this does not work, then you'll have to have the calipers serviced.