Non-Convertible & Flat Collars
Non-convertible collars have a neckline edge that closely mirrors the curve of the body's neckline. When unfastened, they remain seated in place against the shoulder line rather than springing open into lapels.
All variations in this category, from juvenile flat Peter Pan collars to wide sailor bibs and roll-over portrait collars, are drafted directly over the joined front and back bodice patterns.
Anatomy of a Collar
Before drafting, it is essential to understand how the components and landmark edges of a collar interact:
- Neckline Edge: The inner concave seamline that stitches directly to the garment neckline. Its curvature controls the height of the stand.
- Style Edge (Collar Edge): The outer perimeter that defines the collar's visual silhouette (rounded, pointed, or square) and frames the neck and shoulders.
- Collar Stand & Roll Line: The stand is the vertical rise of fabric from the neckline seam up the neck before folding over; the roll line is the crease or fold where the stand transitions into the fall.
- Collar Fall: The portion of the collar that turns over the roll line and drapes downward toward the garment.
- Upper Collar (Top Collar): The visible outside layer when the garment is worn. It is cut slightly larger along the style edge so it can wrap around the inner layers without pulling.
- Undercollar: The facing layer that sits against the body or garment . Shaving its outer edge by 1/16" to 1/8" (1.5–3 mm) creates turn-of-cloth tension, forcing the finished seam slightly underneath so it remains completely hidden from the outside.
- Interfacing: The internal stabilizing layer applied to provide structural support, crisp roll lines, and point retention. In tailored work, interfacing is traditionally fused or pad-stitched to the undercollar to control the roll, while in soft blouses it may be fused to the upper collar. When using fusible interfacings, the seam allowances are trimmed away to eliminate edge bulk.
- Finishing & Facing: Because these collars are set into the neckline rather than enclosed by a band or stand, draft matching front and back neckline facings (or plan for a bias-bound finish) to cleanly encase the raw neckline seam allowances beneath the collar.
Never draft a non-convertible collar onto an unmodified basic sloper unless you intend for the finished neckline to sit snugly at the base of the neck.
Alter your front and back bodice pattern pieces to the desired finished neckline depth and width (including any neck drop, shoulder scoop, or ease adjustments) before overlapping the shoulder seams and tracing the collar foundation. The drafted collar inherits the exact circumference and curvature of the underlying bodice.
The 4:1 Shoulder Overlap Principle
The height of a collar stand at center back is mathematically controlled by how much curvature remains along its neckline seam.
Because the wearer's neck is narrower at the top than at the base, a flat pattern shape behaves according to a fundamental geometric rule:
- A deeply curved neckline seam matches the sloping contours of the shoulder/neck junction. When stitched, the outer style edge has extra circumference, allowing the collar to spread out horizontally and lie flat against the shoulders.
- A straighter neckline seam reduces outer edge circumference relative to the neck base. When forced around the curve of the body's neckline, the collar lacks the outer perimeter needed to lay flat across the shoulders; it is forced upward vertically into a stand before it can roll back down.
How the Ratio Works
To reduce the curve of the collar neckline without drafting from scratch, the front and back bodice slopers are placed touching at the side-neck point. The back sloper is then pivoted inward so that the outer shoulder tips overlap at the armhole.
This overlapping motion closes up the angle between the front and back shoulder seams, which progressively straightens the combined neckline arc.
Patternmakers use the standardized 4:1 Rule:
- Shoulder Tip Overlap = Desired Back Stand multiplied by 4
Every 1" (25 mm) of overlap applied at the shoulder tip reduces the outer style edge curvature enough to generate 1/4" (6 mm) of vertical rise (stand) at the center back.
Ratio Reference Table
| Desired CB Stand Height | Required Shoulder-Tip Overlap | Collar Stand Behavior | Typical Application |
|---|---|---|---|
| 1/8" (3 mm) | 1/2" (13 mm) | Flat-Roll: Lies flat against the shoulders. The 1/8 lift merely clears the neck seam allowance to prevent edge flip. | Peter Pan, Sailor, Bertha, Puritan |
| 1/4" (6 mm) | 1" (25 mm) | Shallow Partial-Roll: Sits slightly off the shoulder with a subtle, tailored lift. | Tailored blouse collars, rounded-point daywear collars, soft oval collars, shaped neckwear over jackets |
| 1/2" (13 mm) | 2" (50 mm) | Partial-Roll (Half-Roll): Climbs halfway up the cervical vertebrae before turning downward. | Half-roll sailor collars, open V-neck/stylized neck collars, classic dress collars, Eton, Choir Boy, Dutch collars |
| 3/4" (19 mm) | 3" (75 mm) | Substantial Roll: Pronounced stand that frames the back and sides of the neck closely. | High-stand Peter Pan, substantial roll collars, shaped shawlettes |
| 1" (25 mm) | 4" (100 mm) | Full-Roll: High stand hugging the nape of the neck, typical for sporty roll collars and tailored Peter Pans. | Sportswear roll, high portrait collar |
As stand height increases, the maximum practical width of the collar decreases. A wide collar with a high stand (1" / 25 mm stand combined with a 4" / 100 mm fall) tends to cup inward, bind against the neck base, and distort the shoulder line. For wide capelets, Berthas, and sailor bibs, keep the overlap at the minimum 1/2" (13 mm).
Even a "flat" collar requires a minimum 1/2" (13 mm) overlap at the shoulder. This creates a tiny 1/8" (3 mm) roll that provides clearance for the seam allowances underneath, preventing the outer edge of the collar from "kicking up" away from the body.
Peter Pan Collar Sample Garment (1/2 scale)
Peter Pan Collar Foundation
The Peter Pan collar is the foundation for all round and pointed flat collars.
Step 1: Bodice Preparation and Setup
- Align the front and back bodice slopers so their side-neck intersection points touch.
- Pivot the back sloper inward over the front shoulder line until the outer shoulder tips overlap by the chosen stand amount. (See the table above for overlap values.)
- If the design features a front button placket, extend the center front (CF) for a standard button extension (typically the button width).
Step 2: Drafting the Collar
- Trace the Neckline: Trace the neckline curve from center back (CB) to center front (CF).
- True the Shoulder Point: Overlapping the shoulders creates a minor angle at the shoulder seam. Smooth and blend this with a curve, removing no more than 1/16" to 1/8" (1.5–3 mm).
- Establish Depth: Measure out from the new neckline curve at right angles:
- Measure desired depth at CB (typically 2"-3" / 50–75 mm).
- Measure equal depth along the shoulder line and towards the front.
- Style the Front Edge:
- Rounded (Classic): Curve smoothly from the outer style line back into the CF neckline intersection.
- Pointed: Draw a straight edge extending from the outer edge to CF.
- Trace the finished collar piece off the slopers.
Sailor & Deep Open-Neckline Collars
Sailor and open-neckline collars utilize an altered base neckline before the collar is drafted.
Step 1: Stylize the Bodice Neckline
- Lower the front bodice neckline along CF to the desired break depth (e.g., 4" to 6" / 100–150 mm below the pit of the neck).
- Draw a straight or gently concave V-neckline line from the side-neck point to the new CF depth.
Step 2: Overlap and Draft
- Place front and back bodices together, touching at the side-neck point.
- Overlap the shoulder tips 1/2" (13 mm) for a standard flat fall.
- Draft the Back Bib: Square a line across CB from the neckline, extending out to the shoulder width or slightly beyond (typically 7" to 9" / 180–230 mm).
- Square downward to the desired depth on the back (typically 8" to 10" / 200–255 mm from CB neck).
- Connect Front Lapels: Draw a straight line from the outer back bib corner across the shoulder to the CF V-point.
- Square off the points at CF by 1/2" (13 mm) to avoid needle fraying during corner turning.
The Undercollar Draft
Because the upper collar must roll around the outer perimeter of the undercollar, making both pattern pieces identical will cause the collar edge to buckle upward and expose the seamline.
- Upper Collar Pattern: Use the master draft above. Cut 1 on fold (or 1 pair if split at CF/CB).
- Undercollar Pattern:
- Trace the master upper collar.
- Keep the neckline edge identical so it fits the garment neck seam without stretching.
- Shave 1/16" (1.5 mm) for lightweight silks and lawns, or 1/8" (3 mm) for woolens and medium-weight woven fabrics, off the outer style edge, tapering to 0 at the CF point.
- Grainline:
- Upper collar: Lengthwise grain on CB fold.
- Undercollar: Can be cut on the straight fold or on a 45° true bias with a center-back seam for heavier tailoring materials.
Drafting Neckline Facings
Because non-convertible collars lack an enclosing collar stand, separate front and back neckline facings are drafted to cleanly sandwich the collar and encase raw neckline seam allowances.
- Trace from the Adjusted Bodice: Always trace the facing directly from the modified front and back bodice neckline patterns, never from the raw sloper or the drafted collar.
- Establish Facing Width: Mark a parallel curve 1.5″ to 2″ (38–50 mm) down from the neckline seam on both front and back bodice pieces.
- True the Shoulder Seams: Ensure the front and back facing shoulder seam lengths match identically.
- Layout Placement: It may be possible to include the front and back facing on one pattern. If not, a shoulder seam is required. Which center is cut on the fold depends on where the neckline opening will be, front or back.
The facing must always finish narrower than the collar fall so its outer edge and anchoring stitches remain hidden beneath the collar shadow.
Verification & Assembly Checklist
- Walk the Seam: Measure the collar's neckline seam against the bodice neckline (Front Neck + Back Neck) to verify a 1:1 match.
- Notches: Place matching notches at CB, the shoulder seam intersection, and CF.
- Corner Truing: Confirm that the neckline seam and outer style edge meet the CB fold at strict 90° right angles to prevent center-back points or dips.
- Interfacing: Cut the interfacing using the undercollar pattern, trimming seam allowances if using fusible fleece or canvas to minimize edge bulk.
- Facing Alignment: Confirm the front and back facing neckline curves match the bodice neckline 1:1, and that the facing width does not extend beyond the collar edge.