A Child's Bodice Block That Shrank
A first-year student drafts a bodice block for a six-year-old girl with chest 60 cm, waist 56 cm, shoulder 9 cm, back neck to waist 26 cm and sleeve length 30 cm. She adds 2 cm ease at the chest and 1 cm at the waist, and 1 cm seam allowance on all seams. She cuts the pattern exactly on the block line at the neckline and armhole, uses a 100% cotton fabric that shrinks 4% in length and 3% in width, and does not pre-shrink it. She sews the side seams at 1 cm with 8 stitches per inch using a 90/14 needle. After the first wash, the chest is tight, the back neck-to-waist measures 25 cm, the armhole seam edge is frayed and the side seam puckers. The teacher must explain the faults and correct the pattern before the garment is graded.
1. Calculate the finished chest and waist length after shrinkage, and explain why the garment is tight even though ease was added.
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The cut chest circumference is 60 + 2 = 62 cm. After 3% width shrinkage, it becomes 62 × 0.97 = 60.14 cm. The child's chest is 60 cm, so only 0.14 cm of ease remains-effectively skin-tight. The 1 cm seam allowances do not add to the finished chest because they are folded inside the seam; they are consumed when the garment is sewn.
The back neck-to-waist length is cut at 26 cm. After 4% length shrinkage, it becomes 26 × 0.96 = 24.96 cm, which rounds to 25 cm, exactly the measured result. The garment is short by about 1 cm.
Two separate faults combine: the original 2 cm chest ease was already low for a woven child's bodice, where about 4–6 cm is usual, and the fabric was not pre-shrunk, so shrinkage removed nearly all remaining ease. Cutting exactly on the block line at the neckline and armhole also means those edges have no seam allowance, which explains the fraying.
2. Recalculate the cut dimensions needed for a finished chest of 64 cm and a finished back neck-to-waist of 26 cm, allowing for the same shrinkage, and state whether pre-shrinking or shrinkage allowance is the better solution.
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Required finished chest = 64 cm. Cut chest = 64 ÷ 0.97 = 65.98 cm, so cut about 66 cm before seam allowance. Required finished back neck-to-waist = 26 cm. Cut length = 26 ÷ 0.96 = 27.08 cm, so cut about 27.1 cm plus any seam allowance at the waist.
The ease should be decided first-64 cm gives 4 cm ease over the 60 cm chest-and the shrinkage allowance should be added outside that, with seam allowance added last. Pre-shrinking the cotton before cutting is the better solution because it stabilises the fabric and removes most residual shrinkage; relying on a calculated allowance is risky if the actual shrinkage differs across the width and length. If pre-shrinking is not possible, cut a test square, wash and measure it, then use the measured shrinkage rather than the nominal 3% and 4%.
3. Recommend seam types and stitch settings for the side seam, armhole and neckline of this cotton garment, and explain the cause of the puckering.
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For the straight side seam, a French seam is suitable for lightweight cotton and encloses the raw edges; allow about 1.2–1.5 cm total, for example 0.6 cm plus 0.6 cm. A flat-fell seam is an alternative for a stronger, sportier finish. For the armhole, a French seam is difficult on the curve; use a 1 cm seam with overlocking or a bias-bound finish. For the neckline, use a bias facing or a bound edge so that the curve lies flat.
Stitch at 12–14 stitches per inch, use a 70/10 or 80/12 needle and a fine polyester–cotton thread, and check the tension on a scrap. The puckering is explained by the 8 stitches per inch, which is too long for lightweight cotton, and the 90/14 needle, which is too heavy and can push the fibres apart. The missing seam allowance at the armhole and neckline also causes fraying and a weak edge. Correcting needle size, stitch density and seam allowance should remove the puckering.