A dial indicator could be mounted eir by back or by stem. Back mounting of dial indicator provides more positive clamping. It is preferred where fixture design mount permits adjustment and space is limited.

Or advantages of dial gauges over conventional gauges are that it is not subjected to gauge wear and re is no effect of temperature variation on instrument. It is a versatile and economic instrument.

To take up backlash, a hair spring is fitted to dial gauge gear trains by a gear and pinion meshing. The gears are precision cut and movement assembly resembles that of high-grade watch to prevent gear from backlash.

Internal dial gauges is a comparison gauge and used to check bore diameters by comparative method. The instrument consists of a hollow tube body which contained a lever pivoted.

The housing of test indicator opens at front only. Single piece construction of side panels and also of bottom surface. The housing encloses totally movement. It provides maximum protection against shock and damages.

The internal dial gauge instrument has three contacts which are spaced equally along circumference of head. Out of three contacts, one is movable and or two are fixed or non-movable type.

A detent is present in passmeter which is used for retracting movable anvil while taking measurement. The spring which is present at back of movable anvil exerts a contact pressure of about 700 ± 200 grammes.

The dial gauge instrument is used in such a way that plunger move sharply in eir direction. So instrument should be made so that by such movement, it will not be damaged and its accuracy and setting will not be spoiled. A knob or finger lever is provided for raising plunger.

Tolerance pointers can be attached to dial face for rapid checking of parts. These pointers can be used to clearly indicate any tolerance, wher bilateral or unilateral, on dial gauge.

The lever and gear movement are used for magnification purposes in a passmeter. It is an indicator gauge and even much more accurate than dial indicator instrument.