Trouser Alterations I: Hem, Taper, and Inseam

Trouser Alterations I: Hem, Taper, and Inseam

Altering woven trousers is one of the most common tasks a custom tailor handles. Three operations appear on almost every ticket: hemming, tapering the leg, and adjusting the inseam length. Doing all three cleanly—and finishing within ¼ inch of the target measurement—marks the difference between journeyman work and professional work.

Safety First

Before touching any machine, review the following:

• Needle hazard. Keep fingers at least 2 inches from the needle path. Never sew over pins; remove each pin before it reaches the presser foot.
• Iron and steam burns. Set the iron to the correct heat for the fabric (wool, cotton, synthetic—check the label). Never leave a hot iron face-down. Keep the steam jet pointed away from your body and other students.
• Serger guards. The serger blade removes fabric as it sews. Keep the guard in place. Reach behind the presser foot to position fabric; never guide material from the front while the machine is running.
• Machine lockout. If you need to change a needle, clear a jam, or oil a machine, turn off the power and wait for all motion to stop before opening any panel.
• Beeswax. Non-toxic, but store it away from the iron plate—melted wax damages equipment and fabric.

Breaking Down the Original Hem

The first step is always to understand how the original hem was constructed before you remove it. Inspect the inside of the trouser leg:

• Is the hem turned up once or twice?
• Was it sewn by machine, blind hem foot, or hand slip-stitch?
• Is there a horsehair braid, twill tape, or interfacing strip?
• Is the crease pressed all the way to the hem fold, or does it stop above it?

Record your observations. Your finished hem must match the original construction details.

Use a seam ripper to release the hem stitches. Work slowly to avoid dragging the point across the face fabric and leaving a snag. Press the released hem allowance flat on the sleeve board, then press out any fold line from the old hem. Re-mark the new hem length with chalk, measuring from the floor or from the specified finished length on the ticket.

Pressing the Crease

On dress trousers, the front crease runs from the waistband to the hem along the center of the front trouser leg. Restore or re-align the crease before you sew the new hem:

1. Lay the trouser leg flat on the pressing surface so the inseam and outseam line up.

2. Press from the knee downward, using a damp press cloth on wool to avoid shine.

3. Use the trouser-specific pressing ham for the upper thigh curve.

4. Allow the fabric to cool and dry before moving it—wet fabric stretches easily.

Sewing the Hem

Machine option (casual/sturdy fabrics): Fold and press the hem allowance to the inside at the marked line. Topstitch from the right side at the specified distance from the fold, or use a blind-hem foot set to catch only one or two threads of the face fabric per stitch.

Hand slip-stitch (dress trousers): Thread a hand needle with a single strand of matching thread; run it through beeswax and press with your fingers to prevent tangling and reduce drag through fabric. Work from left to right. Take a tiny stitch in the face fabric—catching only one or two threads—then a longer stitch through the hem allowance. The hem stitch must be invisible on the face side. Knot off and clip the thread tail inside the hem allowance.

Trim the hem allowance to the width specified on the ticket (commonly 1 to 1½ inches on dress trousers). Finish the raw edge with the serger before turning the hem up if the fabric ravels.

Tapering the Trouser Leg

A taper removes width from the leg, typically from the knee to the hem on both the inseam and the outseam. The taper must be gradual—no abrupt angle—or the finished leg will twist.

1. Try the trousers on the client or dress form. Mark the desired width at the hem and at the knee with chalk.

2. Remove the trousers. Draw a straight tapered line from the knee mark to the hem mark on both the inseam and the outseam.

3. Sew along your marked line. Begin right at the knee chalk mark and sew continuously to the hem. Backstitch at both ends.

4. Trim the seam allowance to 5/8 inch from the stitching line.

5. Finish the raw edges with the serger.

6. Press the seam open, or press it toward the back of the leg, to match original construction.

Check the taper by turning the trouser right-side out and comparing left and right legs side by side.

Adjusting the Inseam Length

The inseam runs from the crotch point down to the hem. Lengthening requires seam allowance in reserve; shortening requires the extra length to be removed and re-hemmed.

To shorten: Measure the amount to remove. Mark the new seamline. Sew, trim to 5/8 inch, serge, and press. Re-hemstitch.

To lengthen: Rip the inseam from just below the crotch curve to the hem area. Press the old seamline flat. Re-sew at a narrower seam allowance to add the required amount. Do not alter the crotch curve itself unless specified—changing the crotch curve changes the fit through the seat.

After any inseam adjustment, put the trousers on the dress form and confirm that the crotch curve lies flat with no drag lines before final pressing.

Final Press and Quality Check

Press every seam as you sew it—press before you move to the next step. On wool, use a damp press cloth and lift-and-press motion rather than sliding the iron, which can stretch bias areas. Allow every pressed seam to cool fully on the sleeve board before folding or bagging the garment.