Measurement

Micrometer Digital Micrometer The micrometer is used for where accurate measurement (to 1000th of a mm) is required. Micrometer

Micrometer Parts Anvil Glass hard and optically flat Spindle Moves ½ mm for every full rotation of the Sleeve Spindle Lock Locks spindle in place Barrel & Sleeve Used to obtain measurements Ratchet Prevents over tightening (and thus damaging) micrometer

Reading a Micrometer When reading a Micrometer it is important to remember that one turn of the spindle represents ½ mm.

Vernier Calipers Named after its inventor the Vernier scale is incorporated in many measuring instruments, the most commonly used of which is the sliding calliper gauge as shown above. These gauges can be used for both internal and external measurement.

Using Vernier Calipers External Measurement Vernier Calipers can be used to measure both internal and external dimensions Internal Measurement

Reading Vernier Calipers Imperial Scale Metric Scale In the illustration above you first read this scale This reads 2.4cm Then you look along the this scale and find where two lines line up This adds a further 0.062mm Add these two figures together to give 2.4 + 0.062 = 2.462cm

Depth Gauge As shown in the diagram on the left the Depth Gauge can be used to measure the depth of holes

Calipers Internal Calipers External Calipers Calipers can be used to gauge the size of an object. As Calipers have no in built scale all dimensions must be set with a rule (as shown). This makes Calipers less accurate than both the Micrometer and Vernier Calipers Setting Calipers

The End