Although it has been around for a long time, the caliper is still an extremely versatile and useful tool for making a wide range of distance measurements (both ODs and IDs). While micrometers are more accurate, they have a limited measurement range (typically several inches). The caliper; on the other hand, can span from 2in to 4ft depending on the length of the scale. External measurements are made by closing the jaws over the piece to be measured, while internal measurements are made by opening up the inside diameter contacts.
PMI falls as manufacturers feel the squeeze
17 months or two and a half years - which is it?