“Deep V” is not a measurable specification. The correct depth depends on the customer’s outer-shirt opening, torso proportions and preference when the undershirt is worn alone. Specify the finished opening for each size, then confirm that geometry on bodies under the intended shirts.
Use one datum and identify the finished edge
Lay the garment flat and relaxed without pulling the neckline into shape. Mark the left and right high shoulder points where the shoulder seam meets the finished neckline edge. Define a horizontal datum through those points in the measurement drawing. Measure front neck drop vertically from that datum to the lowest point of the finished V opening, parallel to centre front. If the garment does not lie symmetrically, record the asymmetry instead of rotating it until the number passes.
A ----------------------- B High-shoulder datum
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V Lowest finished opening pointOther methods can work, including an established brand measurement from a different reference. Do not mix a centre-back-based measurement, a diagonal tape path and a vertical high-shoulder drop in one chart. Nor should the factory measure to the attachment seam while the buyer measures to the inside opening: the band width makes those different dimensions.
Define more than the depth
| Field | What must be agreed |
|---|---|
| Front drop | Datum, vertical direction, finished endpoint and tolerance by size |
| Opening width | Named left/right endpoints, measured relaxed |
| Back drop | Its own datum and endpoint; do not substitute it for front drop |
| Band width | Finished visible width and where it is measured near the V |
| V point | Mitre or overlap construction, centre-front alignment and acceptable flatness |
| Measurement state | Before or after washing; relaxation procedure and sample condition |
Attach a photograph with the measuring tape positioned correctly. Both teams should independently measure the same reference sample before finalizing tolerances. Resolve method disagreement before changing the pattern.
Grade the opening deliberately
Use a size-by-size chart with columns for neck width, front drop, back drop and band width. Record the grade increment separately from the manufacturing tolerance. Do not apply the chest grade automatically to the neck. A larger chest does not guarantee a longer neck or a proportionally deeper outer-shirt opening.
Check the smallest, base and largest sizes on representative wearers, plus any size where the grade changes. Use the same intended collar setting, such as a specified number of open buttons on a reference shirt. Record exposed edge, gaping and pressure rather than only whether the tape measurement passes. After a change to one size, recheck the neighboring grades.
Control sewing and recovery at the point
Specify the band material, cut direction, attachment method and band-to-neckline seam-length ratio using the same seam-line convention. Excessively stretching the garment edge during attachment can distort the opening; an overly short band can pucker it. A ratio approved for one knit or size should not be assumed correct after the fabric, band width or construction changes.
Check whether the V point lies flat, whether left and right sides match and whether the band recovers after donning. Agree a repeatable extension and recovery check with the factory or laboratory, including load or extension, hold time, rest time and measurement location. Do not call an informal hand-pull check a standardized test.
Approve the washed geometry
Record neck width and front drop before laundering, then repeat after the agreed wash/dry procedure and relaxation period. Use care-label settings and a stated cycle count. If the V grows while the body remains stable, examine the band, attachment tension and seam construction. If the body also changes, investigate fabric dimensional stability before correcting only the neckline pattern.
Include width, drop, symmetry and point construction in inspection. Define size coverage explicitly in the sampling plan; an AQL reference alone does not guarantee every size will be measured. Keep the approved washed sample and current drawing with the production file.
When is a second V-depth option justified?
Offer standard and deeper versions when customer use cases support the extra stock complexity. If one depth fails only under a particular shirt, first review the garment combination with the undershirt visibility protocol. Use the development brief to coordinate neckline changes with shoulder, armhole and body-length grades. For a sample enquiry, provide the measured reference and size-by-size requirements through Knitwear Base.
