Dail gauge indicator is a type of mechanical comparator which is used to check variation in tolerances of the manufactured part.

Dial gauge indicator - construction and working | The Mechanical post

Principle of working

The dail indicator works on the principle of converting linear motion of the plunger into the angular movement of the indicator, by using mechanical means. Now-a-days, digital gague indicators are used. 

Construction of dail gauge indicator

The dail gauge indicator consists of:
  • coil spring, 
  • rack guide, 
  • plunger, pinions (P1,P2,P3), 
  • gears (G1,G2,G3), rack, 
  • hair coil spring and an indicating needle.
The assembly of the dial gauge indicator is shown below:


Working of the dail gauge indicator

  • When something is placed under the dail gauge, plunger moves up with rack, pinion P1 rotates and the linear movement of plunger is caonverted into angular movement of pointer. 
  • As pinion P1 rotates, the gear G1 also rotates as it on the same shaft as of pinion P1.
  • Now the gear G1 rotates along with pinion P2, as both are in mesh with each other.
  • As pinion P2 rotates, the gear G2 also rotates as it on the same shaft as of pinion P2.
  • This gear G2 then rotates the pinion P3, upon which the indicating needle is placed. This gives us the reading.
  • While rotating the pinion P3 tends to compress the hair spring which is mounted on the gear G3. This arrengement ensures that the all the dail gague parts come back to their original position; when the objest is removed.

Advantages of dial gauge indicators

  • Easy to read.
  • No need of power supply.
  • Unskilled labours can also use it.
  • Least count up to 1 micro metre is available.
  • Robust design.
  • Gauge wear and such problems are not present.

Limitation of dail gauge indicators

  • Backlash and lagged response may problematic.
  • Play in gears may generate errors.
  • Effect of looseness of measuring spindle guide may give variation.
  • Gear location errors may lead to errors.

Applications dial gauge

  • It is used in dial test indicators.
  • Used as dial caliper gauges.
  • Used in pocket thickness gauge.
  • Used in dial pocket pipe gauge.
  • Used in dial vernier unit.
  • Used as comparator in mass production.
  • Used for sine bar in angle measurement.
  • Used in inspection and setting of job.
  • Used for alignment tests of various tools.
  • Used in Parkinson's great tester.
If you like this post or have any suggestions do let us know in the comments we would love to hear it from you. Do follow The Mechanical post on instagram, facebook and twitter.

Also share this post with friends and family with the social links provided below.