Vernier Caliper with Upper Lock 

The caliper has a dual vernier scale, with both upper and lower scale measuring in millimeters. The scales are raised to slide easily and protect the graduation markings. A thumbwheel permits fast and easy measuring. A clamping screw on the upper scale rotates to control scale movement and locks to hold the sliding jaw’s position. It has two-way measurement capability; knife-shaped upper jaws ensure easy OD measurements and rounded lower jaw measuring faces allow accurate ID measurements. The caliper is made of hardened, corrosion-resistant stainless steel with a satin chrome finish that helps reduce glare. The caliper meets Federal Accuracy Specifications GGG-C-111B.

Calipers measure the distance between two opposing sides of an object. They make inside, outside, depth, or step measurements, according to their type. Calipers are commonly used in architecture, metalworking, mechanical engineering, and machining. The simplest calipers have two legs to mark the two points and require a ruler to take the measurement. More complex calipers use two sets of jaws instead of legs and have up to two graduated scales. Vernier, dial, and digital calipers give direct and accurate readings and are functionally identical, having a calibrated scale with a fixed jaw, and another jaw with a movable pointer that slides along the scale. The vernier caliper has a scale sliding parallel to the main scale for an additional, fractional reading to improve measurement precision. The dial caliper has a circular dial with a pointer on a toothed gear rack replacing the second vernier scale. As with the vernier, this second measurement is added to the reading from the main scale to obtain the result. The digital caliper takes a differential by zeroing the display at any point along the slide, with an LCD that displays a single value in English and/or metric units.