Quick Answer
Dial gauge calibration uses a NABL-calibrated micrometer head or gauge block set to apply known displacements and compares the dial gauge reading against the reference at multiple points across its range. Calibration per ISO 463 covers: repeatability, hysteresis, and 5-point linearity.
Key Takeaways
- Dial gauge calibration per ISO 463 (plunger type) and ISO 9793 (lever/back-plunger type).
- Reference standard: calibrated micrometer head (0.001 mm resolution) or gauge blocks on surface plate.
- Calibration checks: repeatability (3 cycles), zero setting error, and linearity across the range.
- Calibration range: typically 0–10 mm or 0–25 mm with 0.001 mm (1 µm) resolution.
- Prism calibrates Mitutoyo, Mahr, Starrett, Baker, and all major dial indicator brands.
Dial Indicators Calibrated at Prism
- Plunger-type dial indicators (standard face, 0.001 mm and 0.01 mm graduation)
- Lever-type (test) dial indicators (0.001 mm, small angular displacement sensing)
- Digital dial indicators / digital indicators (0.001 mm and 0.0001 mm resolution)
- Long-travel dial indicators (0–50 mm, 0–100 mm range)
- Comparator dial stands (TESA, Mahr) as system calibration
Dial Gauge Calibration Procedure
Mounting on Surface Plate
Mount dial gauge in stand. Bring plunger into contact with reference flat surface. Zero the indicator.
Progressive Displacement
Using calibrated micrometer head or gauge blocks, apply displacement in 0.2 mm increments. Record indicator reading vs. actual displacement.
Hysteresis Check
Return plunger to each displacement point from the reverse direction. Record hysteresis (difference between advancing and retracting readings).
Repeatability
Apply same displacement 5 times. Standard deviation of readings must be < 0.002 mm for Class 0 dial gauges.
Certificate
Issue NABL certificate with error at each calibration point, hysteresis, repeatability, and expanded uncertainty.
Frequently Asked Questions
What is the NABL uncertainty for dial gauge calibration?
Prism achieves expanded uncertainty of ±0.002–0.003 mm (k=2) for 0.001 mm graduation dial gauges, depending on the range being calibrated.
How often should dial gauges be calibrated?
Annual calibration is standard. Dial gauges used in high-cycle production inspection (gauge stands used 100,000+ times per year) should be calibrated every 6 months.
Can Prism calibrate dial gauges with 0.0001 mm (0.1 µm) resolution?
Yes. Prism calibrates digital indicators with 0.0001 mm (100 nm) resolution using Grade 00 gauge blocks and precision measurement equipment.
What is the difference between dial gauge calibration and dial gauge adjustment?
Calibration measures the gauge's error without making any changes. Adjustment (not possible on most dial gauges) would correct the error. Most dial gauges with errors are used with correction factors or replaced. The NABL certificate records the as-found error for user reference.
Does Prism calibrate lever-type (test) indicators?
Yes. Lever-type (or 'test') indicators have a ball-ended plunger that can measure displacement at an angle. Prism calibrates them using a precision sine bar and gauge blocks to apply known angular displacement.
Written by
Er. Parthiv Kinariwala
Managing Director · Prism Calibration Centre · NABL CC-2480 · Ahmedabad
Er. Parthiv Kinariwala founded Prism Calibration Centre in 2004 and has over 20 years of hands-on experience in calibration engineering, NABL accreditation, and industrial compliance. His team performs 10,000+ calibrations annually from the Vatva GIDC laboratory, serving 5000+ industries across Gujarat.
Prism Calibration Centre — Vatva GIDC, Ahmedabad
Prism Calibration Centre
F-101, Rudraksh Complex 2, Phase 3, GIDC Vatva, Near Jasoda Nagar Cross Road, Ahmedabad — 382445, Gujarat, India
Phone: +91 98245 26444
Email: info@prismcalibration.com
NABL: CC-2480 · ISO/IEC 17025:2017
Hours: Mon–Sat, 9:00 AM – 7:00 PM