# How many Uncertainty Measurements for Micrometers and Calipers?

#### garyf2017

##### Involved In Discussions
Hi, I've done some uncertainty measurement for caliper and micrometer but do I need to do uncertainty for every points for example 0-1 inches- I need to do uncertainy for each points? 0 - .5 - .75 etc...

or just the maximum?

TIA.

#### Richard Wilde

##### Registered
Hi there,

Uncertainty of measurement is the error you get when you repeat the measurement and is applied to all the readings.

So, if your measuring at .5 then the uncertainty to measurement will be the same if you are measuring to .75 and across the board.

Does this make sense?

Thanks.

#### dwperron

Trusted Information Resource
Hi there,

Uncertainty of measurement is the error you get when you repeat the measurement and is applied to all the readings.

So, if your measuring at .5 then the uncertainty to measurement will be the same if you are measuring to .75 and across the board.

Does this make sense?

Thanks.

I'm afraid you are dishing out some bad information here.

Repeatability, not measurement uncertainty, is the error when you repeat measurements. It is just one of the components that must be taken into account when you are calculating measurement uncertainty.

Linearity of the tool is another factor in calculating the measurement uncertainty, which is why the uncertainty at 0.5 and 0.75 may not be the same.

In answer to the original poster, you can report the worst case measurement uncertainty for the range of the tool, or you can report the measurement uncertainty of the actual measurement you are making (which is usually smaller).

#### Charles Wathen

##### Involved - Posts
You should have Type A and Type B. Below is what would be used for a micrometer.
Type A would be repeated measurements - micrometer repeatability using 10 measurements.
Type B would include:
Gage block specifications
Coefficient of Thermal Expansion of Gage Block
Micrometer Resolution

G How many Uncertainty Divisors are there for the GUM Application? Measurement Uncertainty (MU) 3
How many nonconformances have you received on average during IATF audits? General Auditing Discussions 24
Too many customer complaints Customer Complaints 16
How many gauges in a Go/No Go Gauge? General Measurement Device and Calibration Topics 7
How Many Processes should be created for each Department? Process Maps, Process Mapping and Turtle Diagrams 5
How Many Notified Bodies are "Enough" Already? EU Medical Device Regulations 23
How many mandays required for the below mentioned standards IEC 27001 - Information Security Management Systems (ISMS) 3
MDR review process by notified body - How many steps exist in the review process EU Medical Device Regulations 0
How many signatures do we need on calibration certificates? ISO 17025 related Discussions 8
Informational From RAPS – Operating System Vulnerabilities in Many Medical Devices, Germany’s BfArM and Device Firms Warn Medical Device and FDA Regulations and Standards News 0
Validation of Medical Device Hardware containing Software - How many to Validate ISO 13485:2016 - Medical Device Quality Management Systems 1
How Many Samples to send for Chemistry Testing Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 3
N MDSAP Participants 2019 - How many companies are participating YTD? ISO 13485:2016 - Medical Device Quality Management Systems 20
S How many of you are using Robotic process automation for calibration lab management? ISO 17025 related Discussions 0
Measuring customer parts on a CMM - How many decimals to report to the customer? ISO 17025 related Discussions 28
J Supplier choice limitation - Many of them dont have PSCR, VDA or even ISO 9001 VDA Standards - Germany's Automotive Standards 0
Clean room performance qualification (pq) - How many times can I do each test? Manufacturing and Related Processes 8
How many samples you require to test during PQ for validation of a equipment? ISO 13485:2016 - Medical Device Quality Management Systems 1
D IATF 16949: Do we have too many processes? Are they all the same? Registrars and Notified Bodies 7
D QMS Performance Based on how many NCRs were generated month to month Nonconformance and Corrective Action 8
S How many QMS processes and procedures? ISO 13485:2016 - Medical Device Quality Management Systems 2
How many of you are Certified to IATF 16949 IATF 16949 - Automotive Quality Systems Standard 12
How many Corrective Action Request can be Issued by DCMA for a single issue? Nonconformance and Corrective Action 2
A Training Program Help - Old docs, new docs, so many docs... ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 6
How many Pieces to Test - Sterility Testing USP EU Medical Device Regulations 2
P Are we an outlier for so many variations of Change Management? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
M SPC with many data points from one dimension Statistical Analysis Tools, Techniques and SPC 16
S How many times do you have the term 'Requirements' in your Quality Manual? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 8
L How many working hours to required to implement ISO 14001 ? ISO 14001:2015 Specific Discussions 6
ISO/TS16949 Internal Auditing - How many auditors? Internal Auditing 4
R Training Production Employees When We Have SOOO Many SOPs Training - Internal, External, Online and Distance Learning 9
Scope Extension Audit - How many days? Do I audit all AS9100 requirements? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 2
J How can I manage Occurence Rates in FMEA efficiently when I have many processes? FMEA and Control Plans 9
How many times the quality agreement has been invoked? ISO 13485:2016 - Medical Device Quality Management Systems 3
C How to document many document control systems with one Document Control Procedure? Document Control Systems, Procedures, Forms and Templates 6
How many laboratories are accredited to ISO 17025 in the USA? ISO 17025 related Discussions 5
R Is it possible to randomly select samples from 1 column to many column Using Minitab Software 2
L How many ISO Standards are there and time allowed for Closing NCs? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 2
How many mandays are required for QMS audit? Internal Auditing 5
FDA - "We Moved Forward on Many Fronts This Year" - Margaret A. Hamburg, M.D. US Food and Drug Administration (FDA) 1
F AS9100 - How many times can the same auditor audit your system AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 1
J APQP Project Management in Excel - Many projects APQP and PPAP 8
S How many production runs will it take for SPC monitoring to stop? Statistical Analysis Tools, Techniques and SPC 10
M How many documents total do you currently have? Document Control Systems, Procedures, Forms and Templates 6
How to Fix this Problem that is caused by so many different issues... Quality Tools, Improvement and Analysis 20
GHTF Releases many documents on Nov 5, 2012 ASQ, ANAB, UKAS, IAF, IRCA, Exemplar Global and Related Organizations 8
How many complaints, defects and non-conformances are typical? Customer Complaints 5
A How many processes for an FDA Quality System (QSR)? 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 7
B How many days after an interview should I follow up on the status of the interview? Career and Occupation Discussions 10
How many trials at least ... Brain Teasers and Puzzles 1