How to Sew a Separating Zipper into a Jacket

A step-by-step guide to installing a professional, durable zipper closure in jackets and coats.

What You’ll Need

• Completed jacket body with finished opening edges

• Separating zipper (correct length + 1–2 inches for adjustments)

• Zipper foot for your sewing machine

• Matching thread

• Fabric markers (chalk or washable pen)

• Pins and/or sewing clips

• Measuring tape

• Iron and pressing cloth

Step-by-Step Installation Guide

Step 1: Prepare the Jacket Opening

• Finish all raw edges with serging or zigzag stitch

• For lined jackets: Baste lining and facing layers together

• Press opening edges flat

• Important: Ensure both sides are exactly the same length

Step 2: Position & Mark the Zipper

1. Lay jacket flat, right side up

2. Place closed zipper along one opening edge

3. Critical alignment points:

   • Top stop aligns with neckline seam

   • Bottom stop aligns with hemline

   • Zipper teeth align with fabric edge

4. Mark top and bottom positions with fabric marker

Step 3: Secure First Side

1. Unzip zipper completely

2. Pin right side of zipper tape to right side of jacket fabric

3. Use clips for thick fabrics like denim or canvas

4. Check alignment: Ensure zipper lies flat without pulling

Step 4: Baste for Precision

• Hand-baste or machine baste with long stitches

• Why baste? Prevents shifting during final sewing

• Remove pins/clips after basting

Step 5: Sew with Zipper Foot

1. Install zipper foot on machine

2. Stitch settings:

   • Straight stitch, length 2.5–3.0

   • Needle position adjusted close to teeth

3. Sewing technique:

   • Start ½” below top stop

   • Stitch close to teeth (approx. ⅛” away)

   • Go slow over stops – don’t hit with needle

   • Backstitch at beginning and end

Step 6: Install Opposite Side

1. Zip up to check alignment before sewing

2. Pin/baste second side, matching precisely

3. Sew using same technique

4. Test function after sewing each side

Step 7: Finish Professionally

For lined jackets:

1. Fold lining over zipper tape

2. Hand-stitch or machine topstitch

3. Press seam toward lining

For unlined jackets:

1. Fold seam allowance over tape

2. Topstitch ¼” from edge

3. Trim excess zipper tape at bottom

Zipper Selection Guide

Troubleshooting Guide

Pro Techniques

Shortening a Zipper

1. Determine needed length

2. Metal zipper: Remove teeth below cut line

3. Coil zipper: Sew across at new length

4. Add new bottom stop with pliers

Finishing Touches

• Press each seam immediately after sewing

• Add bar tacks at top/bottom for reinforcement

• Use contrasting thread for decorative topstitching

• Install pull cover for polished look

Special Fabrics

• Leather/Suede: Use leather needle, tape zipper in place

• Knits: Stabilize with fusible tape before sewing

• Waterproof: Seal seams with seam tape or glue

Quick Reference Chart

Final Quality Check

✓ Zipper opens/closes smoothly
✓ Both sides aligned perfectly
✓ No fabric caught in teeth
✓ Top stops at correct position
✓ Bottom stops even with hem
✓ All raw edges finished neatly

Practice on a sample jacket front first. Mastering separating zippers opens up possibilities for jackets, coats, vests, and sportswear!