Gauge thickness and material weights
What 24 ga, 0.040, 16 oz and 0.7 mm each mean, why a gauge number is not a thickness until a table is named, and how to turn an order line into a decimal thickness and a piece weight. Then how to check delivered sheet and keep the record.
4 lessons · about 37 min · 11 diagrams · 3 videos
Version 1.0.0
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Lessons
0 of 4 complete
Lesson 1 · 9 min · 10 slides · 7 questions
Gauge thickness and material weights: principles and terminology
What "24 ga", ".040", "16 oz" and "0.7 mm" each mean, why gauge runs backwards, where the gauge system came from, and why a decimal thickness belongs on every order.
You will be able to: Explain why a gauge number is not a thickness until a table is named, define gauge, weight gauge, nominal and decimal thickness, and name the four units AFS uses for sheet.
Not startedStart →Lesson 2 · 11 min · 12 slides · 8 questions
Gauge thickness and material weights: materials, standards and design constraints
The three steel gauge tables side by side, why the galvanized table is heavier, how aluminum, copper and zinc are sized, which standards sit behind the numbers, and the AFS limits that depend on thickness.
You will be able to: Read thickness and weight for galvanized and stainless steel, aluminum, copper and zinc from the right table or unit, and state which AFS limits depend on thickness.
Not startedStart →Lesson 3 · 9 min · 10 slides · 6 questions
Gauge thickness and material weights: methods and worked application
An eight-step method from the order line to a recorded weight, worked examples with every input shown, and a micrometer check of delivered stock against its band.
You will be able to: Work from an order line to a documented decimal thickness and piece weight, record the units and the weight basis, and check delivered stock against a tolerance band.
Not startedStart →Lesson 4 · 8 min · 10 slides · 6 questions
Gauge thickness and material weights: defects, verification and case study
The common thickness and weight mistakes, how big each one is, a worked case of delivered sheet that is thinner than its tag, and the record a reviewer needs.
You will be able to: Spot a wrong table, a mislabelled or thin sheet, a missing unit or an unstated weight basis, size the error it causes, and record the evidence for a review.
Not startedStart →
Practical task
Build a thickness and weight sheet for a coping cover order: 18 in girth, 40 ft long, quoted in 24 gauge galvanized, 16 oz copper and 0.040 in aluminum. Then run a receiving check on two delivered coils of the galvanized sheet, using the readings supplied below.
Hand in
- A thickness table: for each of the three materials, the order unit, the decimal thickness in inches, and the table or register it came from
- A weight sheet: area, weight per square foot, piece weight for a 10 ft piece and run weight for 40 ft, each with units and the weight basis stated
- One cross-check by density for the galvanized weight, with the percentage difference from the table weight and one sentence saying which you would quote and why
- A receiving check record for the two coils: coil A readings 0.0265, 0.0268 and 0.0266 in; coil B readings 0.0229, 0.0231 and 0.0230 in; each mean, the band, the decision and the next step
Rubric
| Criterion | Meets the standard when |
|---|---|
| Tables and units | Every thickness is decimal inches with its unit, the table is named, and 24 gauge galvanized is read from the galvanized table, not the U.S. Standard or sheet-steel table. |
| Weights | The 40 ft run areas are 60 sq ft, and the run weights are 69.36 lb galvanized, 60.00 lb copper and 34.08 lb aluminum, with 4 pieces of 10 ft stock for the run, each with the basis written. |
| Cross-check | The density figure for 24 gauge galvanized is about 2.6 per cent below the 1.156 lb table weight, and the sheet states that the table weight is used first. |
| Receiving check | Coil A averages about 0.0266 in with every reading inside the 0.0236 to 0.0316 in band, so it is accepted; coil B averages 0.0230 in with every reading below the minimum, so it is held and reported, the three-reading routine used in this course is stated as a teaching convention and the order or mill certificate as the governing tolerance, and the 26 gauge band is noted without guessing the gauge. |