Measurement tools and calibration
The tape, caliper, micrometer, protractor, square and level and how to read each one; the exact inch; what limits a reading, from tape accuracy and temperature to traceability and certificates; the daily tool check; and the defects that spoil a measurement.
4 lessons · about 52 min · 16 diagrams · 5 videos
Version 1.0.0
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Lessons
0 of 4 complete
Lesson 1 · 12 min · 12 slides · 9 questions
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.
Not startedStart →Lesson 2 · 15 min · 12 slides · 11 questions
Measurement tools and calibration: materials, standards and design constraints
Tape accuracy in NIST Handbook 44 and OIML R 35-1, the 20 °C reference temperature and heat on a 10 ft piece, why a gauge number is not a thickness, traceability and certificates, calibration intervals, and the resolution AFS hems ask for.
You will be able to: State what limits a reading: the accuracy benchmarks for tapes, the 20 °C reference temperature, the effect of heat and of gauge systems on a thickness, the traceability chain and calibration certificates, and the step size AFS sizes demand.
Not startedStart →Lesson 3 · 13 min · 12 slides · 9 questions
Measurement tools and calibration: methods and worked application
The daily tool check; zero first; micrometer, caliper and protractor readings worked step by step; metric readings; rounding to 1/16 in; square and level checks; and the field measurement checklist.
You will be able to: Run a documented tool check, read a micrometer, vernier caliper and vernier protractor and record the result with its unit, convert and round the way AFS does, check a square and a level, and measure in the field against AFS's checklist.
Not startedStart →Lesson 4 · 12 min · 11 slides · 10 questions
Measurement tools and calibration: defects, verification and case study
A bent hook, parallax, Abbe error, force and heat, the wrong tool or unit; a tape checked against a reference; what to do when a tool is out; a corner that is not square; and the record that goes with a reading.
You will be able to: Diagnose the common ways a reading goes wrong, work a tape-against-reference case, choose between re-zeroing, removal and calibration, and write a measurement record someone else can trust.
Not startedStart →
Practical task
Build a measurement job packet for one piece of flashing of your own choosing (or a job you have worked on): choose the tools, check them, read the piece, convert and round the numbers, and record everything so a second person could repeat it.
Hand in
- A decision rationale: for each dimension (leg, run, thickness, hem gap, angle) the tool you chose and the step it shows, with a line on why a finer or coarser tool was or was not needed
- A sketch of the piece with each leg labelled A, B, C, the run length, each bend angle and the painted side marked, and the edge each angle was measured from
- An assumptions sheet with units: every reading written with its unit in inches and millimetres (using exactly 25.4 mm per inch), each labelled as measured, converted or assumed, and the rounding rule you applied
- A tool-check checklist: for each tool, how you cleaned it, checked its zero, checked it against a reference, and what you would do if it were out
- A defect analysis for one reading that went wrong (a drifted zero, a bent hook, an eye off the line, a tilted caliper, heat or a mixed unit): what you saw, the cause, the corrective action and how you re-checked
Rubric
| Criterion | Meets the standard when |
|---|---|
| Tool choice | Each tool is matched to the size it must check, and its step is clearly finer than that size. |
| Readings and units | Every reading is added up from its scale parts, carries its unit, and converts with exactly 25.4 mm per inch. |
| Rounding | Inputs are rounded to the nearest 1/16 in and any sheet allowance down, and the packet says which rule it used and why. |
| Tool checks | Zero, cleanliness and temperature are checked before measuring, and a tool that is out is re-checked, tagged out or sent for calibration, never just re-zeroed and called calibrated. |
| Record | The record names the tool, its zero check, the reading with its unit, the edge measured from, who measured and when, and a second person could repeat it. |
| Safety | Parts are measured off the machine, and hand protection is chosen for sharp edges and jaws. |