Regular calibration intervals help ensure micrometer accuracy.

The inventor of the modern micrometer, Jean Laurent Palmer, introduced the basic principles of magnification based on screw threads. His design is based on a 1-millimeter, single-pitch open screw thread. One rotation, or 1 millimeter, was divided into 20 equal parts, bringing the smallest resolution to 0.05 millimeter. His design was so advanced and complete, that nothing has been added to or subtracted from his original concept in terms of the principles of operation.