How to Sew a Metal Zip – Steps, Needle and Presser Foot

A metal zip is sewn with a zipper foot, a stronger needle (usually size 90–100 for denim and heavy fabrics) and a stitch that runs a few millimetres from the teeth without touching them. The tape is held in place with pins or basting tape and sewn from the bottom up on each side; around the slider the machine is stopped with the needle down in the fabric and the slider is moved. The metal teeth and stops are never stitched over.

How to sew a metal zip – what you need

The metal chain is stiffer and heavier than a coil chain, so it needs a little more preparation when sewing. Here is the basic equipment:

• Zipper foot – a narrow, one-sided foot that lets the needle pass close to the teeth. On industrial machines a compensating foot or an edge foot is used.
• Needle – for jeans, leather and heavy fabrics, choose a denim or leather needle of a suitable size.
• Thread – strong polyester sewing thread; on jeans, often a thicker decorative thread for the visible topstitching.
• Pins, clips or thin double-sided tape – for precise positioning.
• Tailor’s chalk or a fading marker – for marking the stitching line.

Needle by fabric

Steps for inserting a metal zip in a centred seam

This is the simplest option – the zip sits in the middle of a seam, for example on a skirt, bag or cover.

1. Sew the seam up to the end of the opening, closing the upper part where the zip will go with a long basting stitch. Press the seam allowances open.
2. Position the zip face down on the wrong side of the seam allowances, with the teeth exactly on the seam line. Secure with pins or basting tape.
3. Fit the zipper foot to the right or left of the needle, depending on the side you are sewing.
4. Sew from the bottom up about 5–7 mm from the seam line, so that the stitching is parallel to the teeth but does not touch them.
5. Around the slider, stop with the needle in the fabric, lift the foot, move the slider behind the needle and continue.
6. Across the bottom, sew a line below the bottom stop, pivoting the fabric at the corner with the needle down. Do not sew over the stop.
7. Sew the second side the same way and unpick the basting.

Inserting a metal zip in jeans

A jeans fly is more complex, because the zip sits under a fly shield (overlap). The basic sequence:

1. Sew one side of the zip to the underlap of the fly (usually the left side on men’s styles).
2. Sew the fly shield (guard) on the inside.
3. Close the zip, line up the fly flap and sew the second side of the tape to the flap only.
4. Sew the visible decorative topstitching (the J-stitch) from the right side, allowing for the width of the zip.
5. Secure the bottom end of the fly with a bartack that runs below the bottom stop, not over it.

The excess tape at the top is caught in the waistband. Only then are the metal button and the rivets attached.

Inserting a metal open-end zip in a jacket

On jackets the zip is sewn between the outer fabric and the lining or facing. The two halves are sewn separately but must match exactly.

1. Close the zip and mark with chalk on both tapes the levels of the pockets, the collar and the horizontal seams.
2. Separate the zip and sew one half to the front, right sides together, with the box exactly at hem level.
3. Close the zip, transfer the marks to the other front and sew the second half.
4. Add the facing, turn through and topstitch along the edge if the design calls for it.

Checking the marks before sewing the second side is the most important moment – a mismatch of a few millimetres is immediately visible along the pocket line.

How not to break the needle

A broken needle on a metal zip almost always means that the needle has hit a tooth or a stop. To avoid this:

• sew more slowly near the stops and the slider;
• if in doubt, turn the handwheel by hand for the last stitches;
• mark the position of the stops on the fabric in advance;
• if the zip is too long, shorten it first and fit the new stops, rather than sewing over them.

How to fit a metal zip on leather

Pins are not used on leather because they leave holes. The zip is held with basting tape or leather glue, and the stitch is longer so as not to over-perforate the leather next to the teeth. The needle is a special one with a sharp cutting point. Leather cannot be unpicked without leaving marks, so the zip position is checked carefully before sewing.

Common mistakes

• The zip is sewn in wavy because the tape was stretched while sewing.
• The fabric is too close to the teeth and the slider catches it.
• Horizontal seams and pockets do not match on both sides of the zip.
• The top ends of the tape are left loose and stick out.
• The thread is a different shade from the tape and fabric, and the stitching is uneven near the slider.
• The zip was inserted before the test wash, and afterwards the fabric shrank around it.

Metal zips and services from Polkom

Polkom is a manufacturer of metal zips in various sizes, lengths and finishes, suitable for sewing in series production and in ateliers. We also offer sewing threads in matching colours. Send an inquiry – we will prepare samples and advise you on the right zip for your product.