YASTRONICS LABORATORY FOR TESTING AND CALIBRATION
STANDARD OPERATING PROCEDURE YCL/SOP-11
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TITLE: Bore Gauge
STANDARD REFERENCE: JIS B 7533
MASTER AND REFERENCE STANDARD REQUIRED: ULM – Universal Length Machine & Digital Indicator
SCOPE OF CALIBRATION:
Check Repeatability and accuracy over full range.
PRELIMINARY CLEANING AND INSPECTION
Clean the bore gauge using suitable cleaning agent and wipe the gauge using suitable cloth, check for
any damages and report the same
ENVIROMENT CONDITION:
Soak the gauge minimum period of 1 hour at the temperature of 20±1˚C and relative humidity 40 to
60% RH.
PRATICE BEFORE CALIBRATION:
Check the tip of the plunger and check the movement from the start to the end of the entire range,
Record the range and least count of the gauge.
RECOMMENDED METHOD OF CALIBRATION:
1. Fix the bore gauge holder on the ULM bed using Allen key and make sure it not moving and the tight the
ULM free floating screws.
2. Insert the reference standard digital indicator to the UUM and makes sure it is inserted up to the range
of gauge’s moveable anvil and fix it firmly.
3. Place the plunger dial gauge inside the hole of the holder and tight the gauge steam with the screw
given on the side of the holder.
4. Make sure the bore gauge head is straight to the spindle of the ULM (i.e. the moveable anvil should be
straight to the spindle).
5. Fix the flat anvil of diameter 20mm on the spindle and apply 4.5N load on the spindle the spindle should
move from left to right
6. Open the ULM’s display DRO, using fine movement of the spindle touch the anvil face to the tip of the
bore gauge anvil.
7. Apply pressure with flat anvil to bore gauge anvil and make digital indicator to zero, and also preset the
ULM’s DRO to ‘Zero’.
8. Set the least count of ULM for 0.1 µm, using the load applied on the ULM’s Spindle the fine movement is
made through the adjustment knob.
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9. For every graduation the reading is noted in deviation from the difference of nominal value and
measured value (i.e. displayed on the ULM’s DRO).
10. Readings are recorder according the record sheet
11. Take 10 repeated readings for calculating uncertainty using the same procedure.
12. Record the readings on the record Sheet.
PRATICE AFTER CALIBRATION:
1. After the calibration replace standard equipment used for calibration in the appropriate place to avoid
any damage or misplacement.
2. Affix the calibration sticker to the UUM (Unit Under Measurement).
3. Store the calibrated instrument in an orderly manner.
ESTIMATION OF UNCERTANITY:
Uncertainty of measurement is calculated as per NABL 141
REPORTING:
Calibration certificate is prepared as per standard format
