When outside micrometer has a negative error, correct reading can be taken by adding the negative error in the actual reading.

The zero reading (minimum range) of the outside micrometer while measuring with a 50 to 75 mm micrometer is 50 mm.

Dial Test Indicator Tools. Also known as a dial indicator or dial gauge, a dial test indicator (DTI) is a device used in various applications where small distances need to be measured accurately, such as checking run out on brake disks or end float on a crankshaft and concentricity of the outside diameter.

Least Count of an instrument is the smallest measurement that can be taken using an instrument. In other words, it is the smallest change an instrument can measure.