Hems, returns, locks and seams
What hems, returns, locks and seams are for, the three hems FlashDraft draws and the limits that decide whether a hem can be made, worked hem allowances and seam choices, and how to inspect hems and seams and diagnose their common defects.
4 lessons · about 37 min · 11 diagrams · 4 videos
Version 1.1.0
Builds on these modules
Lessons
0 of 4 complete
Lesson 1 · 10 min · 11 slides · 8 questions
Hems, returns, locks and seams: principles and terminology
What hems and locks are for, the three hems FlashDraft draws and which face they fold to, the seam families that join sheets, and the hazards at the edge.
You will be able to: Define hem, return, lock and seam, name the three AFS hems and the main seam families, and state where the safety limits are.
Not startedStart →Lesson 2 · 10 min · 11 slides · 8 questions
Hems, returns, locks and seams: materials, standards and design constraints
The AFS limits that decide whether a hem can be made, the copper seam rules in the CDA details, and why painted coil has its own bend rating.
You will be able to: Apply AFS's hem limits by material and thickness, the CDA copper seam rules, and a coil maker's bend rating, each to the work it belongs to.
Not startedStart →Lesson 3 · 9 min · 12 slides · 6 questions
Hems, returns, locks and seams: methods and worked application
The general two-step hem, the path from FlashDraft to a finished hem, and worked examples: hem allowances, limit checks by material, a short return and seam movement.
You will be able to: Describe how a hem is formed, then check a hemmed profile against AFS's limits, work out its hem allowance and choose between a rigid and a loose seam.
Not startedStart →Lesson 4 · 8 min · 10 slides · 6 questions
Hems, returns, locks and seams: defects, verification and case study
What to check on every hem and seam, the defects that recur and their causes, and a copper seam case worked from finding to decision.
You will be able to: Inspect hems and seams against the order and the sources, diagnose the common defects, and document the evidence and the fix for review.
Not startedStart →
Practical task
Prepare a job packet for a hemmed profile and one seam detail: decide and justify the hems and the seam, check them against AFS's limits and the cited sources, and inspect a formed sample (or, without a shop, a drawn one).
Hand in
- A decision rationale: hem type, return length, hem face and painted side, and the seam type, each with its source
- A marked-up sketch or FlashDraft drawing showing legs, hems, the hem face and the lock or seam
- Material and measurement assumptions: material and thickness from the AFS register, hem allowances worked out, girth, and the FlashDraft status
- A quality checklist completed for the piece: return, gap, face, coating, lock engagement and seam uniformity
- A defect analysis for one defect found or seeded: what it was, the rule and source it breaks, the fix and the check that proved it
Rubric
| Criterion | Meets the standard when |
|---|---|
| Sources | Every value names its owner: an AFS register, the CDA (copper only), the coil maker, or MCA. |
| Limits | The return, thickness rule and girth with hem allowances are checked and the FlashDraft status is stated correctly. |
| Allowance | Hem allowances are worked out by AFS's rule for the hem type, with units, and called a quoting allowance. |
| Hem face | The sketch shows which face each hem folds to and where the painted face ends up. |
| Seam choice | The seam choice accounts for watertightness, movement, metal and slope, with the sources that apply. |
| Defect analysis | The defect is documented with evidence, the rule it breaks, the fix and the verification. |
| Safety | The packet notes hand protection for cut edges and that hands stayed clear of the point of operation. |