Measurement tools and calibration · Lesson 1 of 4

Measurement tools and calibration: principles and terminology

Why every AFS order starts with a reading; the exact inch; the tape, caliper, micrometer, protractor, square and level; resolution, accuracy, calibration, adjustment and verification; and where to stand when you measure.

You will be able to: Name each measuring tool and what it is for, convert between fractions, decimals and millimetres using the exact inch, separate resolution from accuracy and calibration from adjustment, and state the safety boundaries of measuring.

12 min · 12 slides · 9 questions

All lessons in this module

Slide 1 of 12

Every order is numbers

An AFS order is a list of numbers: leg lengths, run length, bend angles and thickness.

AFS's contractor field app keeps every inch a contractor types to the nearest 1/16 in.

A wrong reading is built into the part, so the first measurement is the one that matters most.

Sources

AFS contractor field app inch entry (1/16 in steps) and the FlashDraft sheet allowance - Architectural Flashing Supply

Videos for this lesson

What this video shows: Mitutoyo's own product demonstration of how to use a digital micrometer. Checked against the video's description.

Video: How To Use A Digital Micrometer From Mitutoyo by Mitutoyo America Corporation, on YouTube. Chosen from the video's published description.

What this video shows: Mitutoyo's own product demonstration of how to read a dial caliper. This is a dial type: it shows caliper use, but the dial is read differently from the vernier scale taught in this lesson. Checked against the video's description.

Video: How To Read A Mitutoyo Dial Caliper by Mitutoyo America Corporation, on YouTube. Chosen from the video's published description.

Glossary

Resolution: The smallest step a measuring tool shows, such as 1/16 in on a tape or .001 in on a micrometer thimble. A fine resolution does not guarantee an accurate reading.
Accuracy: How close a reading is to the true value. A tool can have a very fine resolution and still be inaccurate, for example when its zero has drifted.
Calibration: Comparing a measuring tool with standards of known value under stated conditions and recording the relationship between them (international vocabulary of metrology, VIM). The VIM says it should not be confused with adjustment, nor with verification of calibration.
Adjustment: Setting a measuring tool so that it reads as intended, for example re-zeroing it (the VIM lists zero adjustment among the types). The VIM says calibration should not be confused with adjustment.
Verification: Objective evidence that an item, such as a tool or a process, meets stated requirements (VIM). The VIM says verification should not be confused with calibration.
Vernier scale: A short second scale in which n divisions are the same length as n minus 1 divisions on the main scale, so the line that lines up gives the extra digits (Mitutoyo).
Zero: What a tool reads with nothing between its measuring faces (jaws closed, anvils closed). Confirm it before measuring.