Sew fly with zipper in jeans trousers #Z02

1. This is required

Pattern pieces made from outer fabric:

• Front pieces (VH) – 1 pair
• fly facing (ZB) – 1 x
• fly underlay (ZU) – 1 x

Paper pattern pieces

• Front pieces (VH)

Tools and materials:

• the template for the slit stitching out of paper (P-SZ)
• 1 zipper (see instructions or pattern for required length)
• Pins and/or clips
• Hand shears
• Tailor’s chalk or marking pen
• Ruler

2. Produce fly underlay

I fold the bottom of the slit in half lengthwise, right sides together, and sew the slanted bottom edge (below the notch) with a seam width of 10 mm.

Then I turn the piece over and iron it in half from the outside.

3. Sew and turn fly facing

Now I overlock the front edge of the left front piece with the fly facing. First, I shorten the front edge on the left center front piece by 7 mm.

I now place the left fly facing on this edge, flush from the top, right to right, pin it in place and mark the end of the slit at the notch mark. Until then, I topstitch the pieces together with a straight stitch at a seam width of 10 mm. I secure the slit end with forward and backward stitches.

I cut the seam allowance until just before the last stitch.

Before I turn the facing, I press over the seam allowance. You can now topstitch them down on the facing side with a 2 mm gap or topstitch them in the next step using contrasting thread.

I then fold the fly facing inwards at the seam and iron it in place. The lower, loose cutting edge of the facing is placed towards the cut edge of the front piece. Depending on the design, the front edge of the slit can now be stitched with contrasting yarn.

4. Neaten the cut edges

The round raw edge of the fly facing, the crotch seams of both front pieces, the front edge of the left front piece and the open edges of the pressed fly underlap are now finished. I use my overlock machine for this.

5. Sew on zipper on the right side

The measurement of the required zipper length is noted in the instructions and on the pattern for the front piece. You can also determine it by measuring. It corresponds to the length at the front center from the clip to the upper edge minus 15 mm.

On the right front piece, I mark 8 mm from the front cutting edge and 15 mm from the top edge. I place the zipper tape right sides together at this marking (with the slider facing the right side of the fabric) and topstitch it on close to the edge.

Then I fold the zipper over so that the right side is visible. I topstitch the seam narrow-edged on the front piece.

6. Connect the front pieces

Now merge the two front pieces together. To do this, I lay the front pieces right sides together and sew the lower front seam together right up to the slit end with the seam width marked in the pattern.

I then stretch the seam allowance in the curve when ironing. The suture itself should not be stretched so much.

7. Sew on zipper on the left

On the right front piece, I now draw the center front 7 mm parallel to the zipper line.

I line up the left front edge with this line and pin it in place.

Then I turn the front pieces to the wrong side and pin the zipper to the facing. It is helpful to place a hand measure or ruler under the fly facing to avoid pinning the front piece.

I then sew on the zipper with a narrow edge distance. You can secure the ribbon with a second additional stitch.

8. Fly topstiching

Now I place the fly template on the left front piece and draw the slit.

I pin the fly facing and front piece together.

There are many options for designing the fly and the short inseam. The slit can be single or double-stitched, as can the short crotch seam below the slit. You can work with a cross or lengthwise bartack at the end of the slit. However, the latter is only done after the fly underlay has been attached.

9. Connect the fly underlay

From the inside, place the fly underlap over the fly facing and pin it to the seam allowance of the right front piece with the overlocked long edge.

From the end of the slit to the top of the waistband edge, I sew the slit facing in place.

The bottom of the slit is connected to the slit facing with a short seam or bartack on the opposite side.

10. Fly bartack

As described above, you can secure the end of the slit with a bartack. In this example, I have worked with a narrow zig-zag stitch with a stitch width of 1.5 mm and a stitch length of 0.4 mm. I tried out the stitch on a test piece before sewing it onto the pants.

11. Finished slit with zipper

And this is what the finished fly with zipper looks like.

Below you will find the link to the next step:

• Sewing yoke and back seam on jeans #HH01

If you’re not quite ready yet and perhaps want to start at the beginning, you’ll find some links here:

• Preparing the pattern for cutting
• Cutting fabrics and materials
• Sew side pocket in denim pants #TV02