Unstructured Blazers: Shoulder, Armscye and Sleeve Pitch

An unstructured blazer is a shell of cloth with a lightly built front and almost nothing in the shoulder. It is sold as comfort, and it is comfortable. What it is not is forgiving. A structured jacket hides a quarter inch of shoulder drift inside its canvas; a soft one puts that quarter inch on the wearer, where it reads as a collapsed shoulder long before anyone has said a word about it.

What soft construction removes

A structured jacket carries a floating layer of canvas through the chest, a shoulder pad of a quarter inch or more, and a lining. The canvas is tacked rather than fused, so it holds a curve while letting the cloth move over it. That assembly is what corrects a shoulder that slopes more on one side, or a chest that sits forward of the spine, without the wearer doing anything.

A soft jacket keeps a lightweight front, sometimes a strip of tape along the shoulder seam, and padding that runs an eighth of an inch or less. Remove the canvas and the cloth has nothing to hold a line against except the body underneath. The jacket does not drape badly. It drapes honestly, which is a different problem.

Shoulder seam placement

The seam should land on the acromion, the bony point at the top outer corner of the shoulder, or within a quarter inch of it. Soft jackets usually extend it by a quarter to half an inch to get the relaxed line the category promises. That extension works on a wearer whose shoulders are level and less well on one whose are not.

To check, measure from the center back of the neck to the acromion with the arm hanging, then compare that half-width against half the garment’s shoulder width, taken flat and seam to seam across the back. Brands differ on whether the published shoulder figure includes seam allowance, so measure the jacket rather than trust the chart. The placement of that seam matters more on a jacket with no padding, because there is nothing between the cloth and the bone to blur the edge.

Chest ease and the armpit fold

Chest ease is garment chest minus body chest. On a soft jacket it runs about 1.5 to 2 inches; a structured jacket carries 2 to 3 and spends the surplus on a clean front. Take the body measurement at the fullest point of the chest with the tape level and the arms down, then measure the jacket flat from pit to pit and double it. A jacket reading 40 inches across the chest on a 38-inch body has 2 inches of ease.

Above about 2.5 inches, an unstructured jacket has nowhere to put the surplus. It falls into a vertical fold running from the armpit toward the hem, and steaming will not remove it, because the fold is excess cloth rather than a crease. Taking in the side seam recovers most of an inch. Beyond that the armhole starts to close and the sleeve stops hanging cleanly, which trades one visible fault for another.

Armscye depth decides whether the jacket rides up

The armscye is measured from the shoulder seam straight down to the underarm seam, perpendicular to the floor, on a jacket laid flat. On a size 6 to 8 soft jacket it usually falls between 8 and 9 inches. A low armhole runs 10 to 11; a high one, about 7.5.

Depth decides how the jacket behaves once the arms leave the sides. A deep armhole feels generous in front of a mirror, because the sleeve hangs away from the body and the jacket looks roomy. Sit down and reach forward as if for a keyboard and the same sleeve pulls the side panel with it, lifting the hem. Canvas absorbs part of that travel in a structured jacket. In a soft one nothing absorbs it, which is why a low armhole is the most common reason a jacket looks right standing and wrong at a desk.

Sleeve pitch is the one you cannot buy back

Pitch is the angle at which the sleeve is set into the body, typically 5 to 8 degrees forward of a straight line, and more on a rounded upper back. Set too far back, the sleeve twists, throwing a diagonal fold from the shoulder blade toward the elbow and pulling the cuff backward. Set too far forward, the fold appears across the front of the upper arm and the cuff turns outward.

Neither fault is a length problem, so hemming does not touch it. Resetting a sleeve means removing it, recutting the armhole and rehanging the sleeve head, three to four hours of work before anything is sewn back on. Most workrooms decline the job on a finished jacket, and the ones that accept quote close to the price of the garment. This is the number to check in the fitting room, because it is the one that cannot be bought back later.

Where the advice stops working

The ranges above assume a shoulder slope within about half an inch of level and a chest that does not project far past the shoulder line. Outside that, soft jackets get difficult and the standard advice stops applying.

Very sloped shoulders need a quarter inch of pad at the seam, or the jacket collapses into a divot beside the neck. A large chest needs ease to close the front, but soft cloth folds where structured cloth would hold, so a half-canvassed jacket with a light front is the better compromise. Shoulders under about 15 inches across benefit from a shorter extension, or the jacket reads as borrowed from someone larger. A wearer who wants no padding at all is better served by a shirt-jacket or a chore coat, both of which are cut for that shape instead of fighting it.

What a tailor can still change

Sleeve length is straightforward: three quarters of an inch on a cuff with working buttonholes, up to an inch and a half on a plain one. Waist suppression runs half an inch to an inch depending on the seam allowance the maker left, and hem length is simple on an unlined jacket.

Shoulder width beyond a quarter inch, armhole depth and pitch are effectively fixed. Budget alterations on that assumption, which is the same rule that governs which alterations are worth paying for. A jacket bought a size up to fix the chest will need the shoulders rebuilt, and that is not an alteration; it is a remake with a new pattern.

Cloth and the office it is worn in

Soft construction suits cloth with surface texture: wool flannel, linen blends, cotton twill, hopsack. Texture scatters light and hides the small ripples that a smooth worsted with a sheen will show at the chest and the sleeve head. Weight matters too. A 250 to 320 gram cloth holds a lapel roll through a working day; below about 240 grams the jacket behaves like a shirt-jacket and the collar will not stand.

Lining is a climate decision rather than a quality one. Unlined for a heated office in summer, half-lined in wool for the rest of the year. If the jacket will be worn over a tee more often than over a shirt, the ease numbers shift slightly, and the tee, blazer and trouser formula sets them out. The wider comparison of construction at each price sits in how blazers differ.