Sew fly with concealed button placket in jeans trousers #Z03

1. This is required

Pattern pieces made from outer fabric:

• Front pieces (VH) – 1 pair – with pockets already incorporated
• fly facing (ZB) – 1 x
• fly placket (ZBK) – 1 x
• fly underlay (ZU) – 1 x

Pattern pieces from interlining:

• fly placket (EZBK) – 1 x

Tools and materials:

• Template for fly stitching (P-SZ)
• Buttonhole template (P-KS)
• Pins and/or clips
• Hand shears
• Tailor’s chalk or marking pen
• Ruler
• Buttons for the fly placket
• Punch pliers and awl for eyelet buttonholes if necessary

2. Produce fly underlay

I fold the bottom of the fly in half lengthwise, right sides together, and sew the slanted bottom edge, where the side notch are, together with a 10 mm seam width.

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 at the center front by 10 mm. This cutting line is also marked in the pattern, so you can use it as a guide.

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. The slit end is secured with forward and backward stitches.

The seam allowance is cut in just up to 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. Prepare the button placket

The interlining is now ironed onto the wrong side of the button placket.

The button placket is then folded in the middle on the long side and ironed in place.

5. Overlocking the cutting edges

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

6. Work buttonholes into the placket

I now mark the buttonhole position on the fly placket. To do this, I place the template flush and transfer the front point of the buttonhole eye. I then draw the course of the buttonholes parallel to each other.

Tip

If you place the template with the printed side facing up on your pattern piece, the top/beautiful side of the buttonholes will later be on the underside of the button placket – so you can see them from the inside when you open the slit completely. If you prefer to have the upper side buttonholes on the upper side of the pattern piece, you must mirror the template.

I embroider the buttonholes with the appropriate presser foot and program on my sewing machine. I first make a sample on a test piece. If you do not have such a program on your machine, you can mark the length of the button and embroider the long bartacks with a narrow zigzag stitch. Then use a correspondingly wide zigzag stitch for the bartacks at the beginning and end.

I punch out the eye of my buttonhole with a 2 mm diameter punch. I place a piece of fabric under the strip so that I cut the fabric in the strip completely. I then carefully cut open the buttonholes so as not to cut any stitches.

7. Fly topstiching

Now I can mark the course for the fly stitching on the left front piece. To do this, I place the paper fly template so that it rests against the front turned edge and the top edge.

Then I turn the front piece, place the fly placket 2 mm away from the front edge and pin it in place.

I then stitch through the slit from the outside. For better durability, I topstitch a second seam at a distance of 5 mm from the front. This secures the concealed button placket under the front.

8. Connect the front pieces

The two front pieces are now joined together. To do this, I lay them right sides together and pin them together at the crotch seam.

The seam is now closed exactly from the slit end to the leg seam 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.

9. Sew on the underlap

I place the bottom of the slit with the serged long edge on the edge of the right front piece and pin it in place.

From the front side, I topstitch the underlap with a 10 mm seam width.

Then I turn the underlap to the right side and topstitch the seam with a 2 mm gap on the front piece.

10. Connect center front

On the right front piece, the center front is 10 mm parallel to the seam of the underlap. It is also marked with a notch on the edge of the waistband.

Place the left front edge at this position and pin in place.

11. Design of fly and inseam

Before I finish the fly and the crotch seam, I flatten the layers a little with a hammer. I use a wooden board as a base.

I cover the slit end from the outside with a piece of fabric so that my fabric is not damaged in the process.

Variants for the fly design

The crotch seam can then be overlocked. There are many options for designing the fly and the short inseam. You can single or double topstitch the slit, as well as the short crotch seam below the slit. You can work with a cross or longitudinal bartack at the end of the slit. I am showing variant 1 here.

When topstitching the crotch seam, it helps to stretch it slightly to avoid creases.

Secure slot end

I secure the end of the slit with a bartack. I chose a narrow zig-zag stitch with a stitch width of 1.5 mm and a stitch length of 0.4 mm. I also have to fix the bottom of the slit. I also placed a bartack here (above the end of the slit in the curve; not too high, so that I can still fold the strip apart easily).

If you do not want this second bartack for the underlap to be visible from the outside in the fly stitching, fold back the front piece and lock the seam allowance of the facing to the underlap from the inside.

12. Attach buttons

Last but not least, I attach the buttons. To do this, I fold the overlap to the side and mark the button position on the underlap through the eyes of the buttonholes. I can now sew my buttons on there or fasten the jeans buttons.

I attach jeans buttons and prepare the appropriate tool by inserting the holders. Then I put the button and button base inside.

I widen the fabric at the marked button positions with an awl to make it easier to push the pins of the button bottoms through the fabric.

I now push the inserted lower part through the opening from below.

Then I fold the side with the top over and hammer the button together.

13. Finished fly with button placket

And this is what the finished slit with the concealed button placket 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 your own jeans front pocket on denim trousers #TV02