Vernier caliper parts

All vernier calipers contain the same basic parts whether they are inch or metric reading. Larger verniers, which have a single set of jaws used for both O.D. and I.D. measurements, have a scale for outside measurement on one side of the bar and a scale for inside measurement on the other.
The basic parts are:
�?The frame is L-shaped. The long portion os the bar and the short portion is the fixed jaw.
�?The bar contains the main scale and is graduated with outside measurements on one edge and inside on the other.
�?The movable jaw consists of a vernier scale for either inch or metric measurement.
�?Clamp screws lock the movable jaw.
�?An adjustment nut is used for fine adjustments.
Some vernier calipers are available in both inch and metric graduations, with an inch scale on one edge and a metric scale on the other.