Standard Calibration Procedure
Doc. No. Call/SCP/006 Rev. 00 May 01, 2015
Micrometer
STANDARD CALIBRATION PROCEDURE
MICROMETER
Prepared by
Muhammad Ajlan Signature Date : 01.05.2015
Reviewed by
Muhammad Sarwar Signature Date : 01.05.2015
Approved by
Qaswar Mehmood Signature Date : 01.05.2015
Controlled Copy No. Uncontrolled Copy
Issued to :
Page 1 of 4
Standard Calibration Procedure
Doc. No. Call/SCP/006 Rev. 00 May 01, 2015
Micrometer
This document is the property of Qstar Engineering, and is issued only for persons or entity as
written on this document. It is not to be retransmitted, printed or copied without prior written
permission of company.
Table of Contents
Sr. No. Title Page No(s).
1.0 Scope 03
2.0 Standard Equipment 03
3.0 Preliminary Operations 03
4.0 Calibration Procedure 03~04
5.0 Related Documents 04
Page 2 of 4
Standard Calibration Procedure
Doc. No. Call/SCP/006 Rev. 00 May 01, 2015
Micrometer
1.0 Scope
This procedure provides guidelines for calibration of Micrometer.
2.0 Standard Equipment
2.1 Gauge Block Set with a valid certificate of calibration either traceable to international or
national standard laboratory in accordance with an industrial code or regulation shall be
used as a standard for calibration.
2.2 The standards for calibration shall be kept under controlled environmental conditions e.g.
dust free environment and Lab temperature 22°C ± 3°C.Lab Humidity 60%RH ± 20%RH.
3.0 Preliminary Operations
3.1 The details of micrometer received for calibration shall be entered in the Calibration Job
Form (Form: Call/001).
3.2 It shall be ensured that the micrometer measuring surfaces are free of dirt, nicks and
burrs. The micrometer can be adjusted through its entire range with no signs of sticking
or binding.
4.0 Calibration Procedure
4.1 The measuring rods of depth micrometers shall be checked for bends by hand rolling on
the surface plate
4.2 To ensure uniformity in the calibration of the ratchet type micrometers,, it shall be placed
to the reference plane of the standard, holding it firmly in place with one hand. utilizing a
slight rocking motion on the frame of the micrometer. Simultaneously the micrometer
ratchet shall be closed until there is no more rocking motion indicating that the axis of the
micrometer is perpendicular to the reference plane.
4.3 The zero reading of the micrometer shall be adjusted by bringing spindle and anvil
together or by inserting an appropriate gauge block stack between the spindle and anvil.
Adjustment shall be made as near to zero as possible. The zero reading must not
exceed ±1 division.
Page 3 of 4
Standard Calibration Procedure
Doc. No. Call/SCP/006 Rev. 00 May 01, 2015
Micrometer
4.4 The zero reading of the depth micrometer shall be adjusted by bringing the micrometer
base in contact with a known flat surface (gauge block face). And adjustment shall be
made as near to zero as possible. The zero reading must not exceed ±1 division.
4.5 Linearity Calibration
The micrometer shall be inspected and marked () in relevant block of equipment’s
primary inspection section of Calibration Data Sheet (Form: Call/013).
The micrometer to be calibrated shall be maintained at same place of Standard
(Gauge block set) for 24 hours minimum.
The micrometer shall be checked with appropriate size gauge block or blocks, at
approximately 20, 40, 60, and 80% of full range.
The gauge blocks shall be placed on working surface with both ends or working
surfaces exposed.
The inside of the micrometer anvil and spindle shall be placed over the ends or
working surfaces of gauge block making a rough setting and tighten with ratchet if
applicable.
The readings of micrometer shall be recorded in observed value column against the
standard readings in set value column of Calibration Data Sheet (Form: Call/013).
Write the action taken in relevant block of operation involved section of Calibration
Data Sheet (Form: Call/013).
The inside micrometer calibration is similar to the out side micrometer except the
anvil and spindle of micrometer are set to the inside of the Gauge block caliper jaws
and the measurements or readings should be the total length of gauge blocks
between the caliper jaws.
Parallel check of anvil and spindle shall be performed by closing them and checking
for light wedge.
The micrometer shall be adjusted to zero / minimum reading position and the
equipment shall be secured.
The micrometer shall be cleaned and lubricated if required.
Calibration Certificate (Form: Call/002 shall be issued for calibrated micrometer as
per Calibration Data Sheet (Form: Call/013).
A Calibration Sticker (Form: Call/003) containing following information shall be
affixed on the calibrated micrometer.
a) Item code
b) Calibrated on
c) Next calibration date
5.0 Related Documents
All the latest formats are documented in Master List of Document / Record and placed in CQF
file for reference.
All the latest Standard Calibration Procedures (SCP) are controlled and issued to concerned
Calibration Engineers.
Page 4 of 4
