Operation & Calibration of Screw Gauge (Micrometer)

-

🔧 STANDARD OPERATING PROCEDURE (SOP)

Operation & Calibration of Screw Gauge (Micrometer)

🎯 1. Purpose

To establish a standardized procedure for the calibration and correct operation of a screw gauge to ensure accurate, reliable, and traceable measurements in accordance with good laboratory and regulatory practices.


📌 2. Scope

  • Educational laboratories
  • Physics & engineering practicals
  • Quality control and inspection labs
  • Routine dimensional measurements

📚 3. Regulatory & Reference Guidelines

  • ISO/IEC 17025 – Calibration & measurement accuracy
  • ASTM measurement practices
  • NABL / GLP laboratory guidelines
  • Manufacturer’s instruction manuals

🧰 4. Equipment Required

  • Micrometer Screw Gauge
  • Calibration standard / gauge block (if available)
  • Clean lint-free cloth
  • Sample object (wire, sheet, component)

⚙️ 5. Parts of Screw Gauge

  • Anvil – Fixed measuring face
  • Spindle – Movable measuring face
  • Sleeve – Main scale
  • Thimble – Circular scale
  • Ratchet Stop – Uniform pressure
  • Lock Nut – Fixes the reading

⚠️ 6. Safety & Handling Precautions

  • Always use the ratchet knob for final tightening
  • Do not overtighten the spindle
  • Ensure measuring surfaces are clean
  • Avoid dropping or exposing to moisture
  • Store in protective case after use

🧪 7. Calibration Procedure (Zero Error)

  1. Clean the anvil and spindle surfaces
  2. Close the gauge gently using the ratchet stop
  3. Observe zero alignment on circular scale
  4. If zero coincides → No zero error
    If zero is below reference line → Positive zero error
    If zero is above reference line → Negative zero error
  5. Record zero error and apply zero correction

📏 8. Least Count

Least Count = Pitch of Screw ÷ Number of divisions on circular scale

Example: Pitch = 1 mm, Divisions = 100
Least Count = 0.01 mm


📐 9. Measurement Procedure

  1. Place object between anvil and spindle
  2. Rotate thimble gently until contact is made
  3. Use ratchet stop for uniform pressure
  4. Note Main Scale Reading (MSR)
  5. Note Circular Scale Reading (CSR)
  6. Observed Reading = MSR + (CSR × Least Count)
  7. Final Reading = Observed Reading ± Zero Correction

📝 10. Observation & Documentation

  • Take minimum three readings
  • Record values clearly in tabular form
  • Calculate mean value
  • Mention calibration status

🧹 11. Post-Operation Care

  • Clean measuring faces after use
  • Release spindle pressure
  • Store in dry, padded case

❌ 12. Common Errors

  • Ignoring zero correction
  • Applying excessive pressure
  • Dirty measuring surfaces
  • Improper alignment of object

✅ 13. Conclusion

Adhering to this SOP ensures accurate measurements, compliance with laboratory regulatory practices, and prolonged instrument life.

© 2026 sopnest.blogspot.com. All rights reserved. This content is independently written and intended for educational purposes. References to regulatory guidelines are for compliance guidance only.

Comments

Post a Comment

Popular posts from this blog

-
⚠️SOP for Risk Management and Risk Assessment (FMEA, RPN, HAZOP, SWOT) This Standard Operating Procedure (SOP) describes a comprehensive risk management and risk assessment framework using FMEA, RPN, HAZOP, and SWOT methodologies. It supports pharmaceutical quality systems in accordance with ICH Q9 and ISO 31000 for effective identification, evaluation, mitigation, and monitoring of risks. 1. Introduction Risk Management is a structured approach to identify, assess, mitigate, and monitor risks in laboratory, R&D, QC, manufacturing, and quality systems. This SOP provides step-by-step instructions for multiple risk assessment techniques, including FMEA, RPN, HAZOP, and SWOT analysis, ensuring robust evaluation, prioritization, and mitigation of risks. 2. Purpose To establish a standardized framework for risk identification, analysis, evaluation, mitigation, monitoring, and continuous improvement using multiple validated risk assessment techniques, ens...
Read more

SOP for Operation and Calibration of UV-Visible Spectrophotometer

-
SOP for UV-Visible Spectrophotometer Operation & Calibration SOP for UV-Visible Spectrophotometer Operation & Calibration SOP Code: [Assign Code] Version: 1.0 Effective Date: [Insert Date] Review Date: [Insert Date] Prepared by: [Name / Designation] Approved by: [Name / Designation] 1. Purpose To provide detailed instructions for safe operation, calibration, and verification of UV-Visible spectrophotometers in compliance with IP, USP, BP, and EP standards to ensure accurate and reliable analytical results. 2. Scope This SOP applies to all analysts and QC personnel performing routine or validation analysis using UV-Visible spectrophotometers. 3. Responsibilities Role Responsibility Analyst / Technician Operate the instrument, prepare standards, perform calibration, and record results. QC / QA Officer Review and approve calibration logs, ensure compliance with pharmacopeial requirements. Maintenance Personnel Perform preventiv...
Read more

Operation and Calibration of Tap Density Apparatus

-
Operation and Calibration of Tap Density Apparatus 1. Purpose To establish a standardized and detailed procedure for the operation, calibration, and maintenance of the Tap Density Apparatus used for determination of bulk density and tapped density of powders, granules, and solid materials in accordance with pharmacopeial and GMP requirements. 2. Scope Quality Control laboratories Research and Development laboratories Production and in-process testing laboratories Any department performing bulk and tap density analysis 3. Definitions Bulk Density: Mass of powder divided by its untapped volume. Tapped Density: Mass of powder divided by the volume after mechanical tapping. Tap Density Apparatus: Instrument that mechanically taps a graduated cylinder to obtain reproducible tapped volume. Carr’s Index: Measure of compressibility calculated from bulk and tapped density. Hausner Ratio: Ratio of tapped density to bulk density. ...
Read more