1. Establish that this is the most excellent instrument you have available for the exact measurement. Do not use basically because it is handy.
2. In detail clean both the part and the caliper. (Make it a practice to repeatedly make sure all contact surfaces of the part and the apparatus for burrs or other obstructions.)
3. Release the clamping screws on both the changeable jaw and the nut carrier.
4. Place movable jaw slightly bigger than feature to be measured.
5. Fasten nut carrier to the beam. Snug up but do not lock the clamping screw on the changeable jaw.
6. Position the fixed jaw in get in touch with with the reference point of the part feature.

7. Assemble in a line the beam of the caliper to be as practically parallel to the line of measurement as possible–in both planes.
8. Revolve the adjusting nut so that the changeable jaw just contacts the part. Constrict clamp screw on the changeable jaw exclusive of distressing the feel between the caliper and the part.
9. Read in place without disturbing part of the caliper, if possible, if not, remove the caliper.
10. Record the reading on scratch paper; chalk on part, or on part drawing. Do no rely memory.
11. Duplicate the measurement steps a adequate number of times to rule out any apparently inaccurate readings and regular the others for the preferred measurement.
12. Release both clamps, slide movable jaw open, and take out work, if your finish.
13. Clean, lubricate and restore instrument in its box.
14. Ask yourself, what errors may remain in your measurement