Any measuring equipment can turn defective due to a variety of reasons. Dial gauges are such tools that may show faulty readings due to incorrect settings or slipped teeth.
How does dial gauge work?
The Dial Indicators’ working principle is that the movement of the spindle multiplied with the reading of the main scale due to the indication of the needle. A dial gauge or indicator is basically used to estimate the distance between two plates. The best way to rectify the wrong readings and get accurate figures is to calibrate the indicator.
How to calibrate dial gauge?
To calibrate Dial Gauge, you need a gauge stand, a surface plate, and appropriately sized gauge blocks. The dial indicator needs to be mounted on a gage stand on the surface plate. In the next step, zero is set on the dial, then gage blocks are inserted, and dial indicator reading is taken to determine that it is functioning properly. For calibrating a dial gauge, you need to do a little maneuvering with its plunger while keeping an eye on the readings given by the indicator.
Given below are the detailed steps of the plunger dial gauge calibration procedure:
- Firstly, clean off the dirt and debris from the gauge blocks, surface plate, and the plunger’s tip.
- Then, lock the indicator in its place on the stand in such a way that it rests adequately high to let the plunger move to its complete length and yet also stays in a position to touch the surface plate.
- Place the plunger’s tip on the dial’s surface plate. Thereafter, spin the indicator’s face till the ‘0’ marking lines up with the dial.
- Lift the plunger and then slide the 0.020-inch gauge block beneath it.
- Keep the plunger on the gauge block’s surface. And ensure that the indicator displays the reading as ‘0.020-inch’. Check twice that the gauge shows the same reading simultaneously by lifting and placing the plunger repeatedly.
- Now, repeat the same with 1-inch, 0.400-inch, 0.250-inch, 0.100-inch, 0.050-inch, and 0.025-inch blocks. Examine every block at least three times for the indicator’s reading.
In case the gauge’s plunger is at a 2-inch depth, pile up the blocks to verify the indicator’s reading at 2-inch, 1.400-inch, 1.250-inch, 1.100-inch, 1.050-inch, and 1.025-inch increments too.
If the readings deviate by an increment of over ‘1’ across the initial 2-1/3 dial revolutions, you need to reject the indicator. Thereon, shift the reading by one increment for every complete rotation of the dial. Besides, you need to adjust the relevant offset value by mental calculations while taking the readings.
Note:
The dial gauge needs to be calibrated daily if you seldom use the device. If you are using a dial gauge at your workplace, you may follow the standard tooling procedures available at the facility.