This was originally part of the full garment tutorial, which got too long. Decided I'd split that and give the pocket its own post here.
This is how to add piping to a lined patch pocket which can then be folded over to create a faux flap.
You will need two pieces of fabric the size of your pocket - one for the outside of the pocket and the other for the lining*. You will also need piping. The seam allowance of the fabric pieces should match the seam allowance of the piping (usually about 3/8").
*In a three-layered pocket (like an inset pocket), we call this backing layer "the "facing. For this two-layered patch pocket, we'll stick to calling this "the lining".
Begin with one of the fabric pieces, right side up. This will be the outer layer. Use a regular zipper foot with the needle aligned to the leftmost position.
Line up the seam allowance of the piping with the seam allowance of one side of the fabric piece. The piping cord should face lie away from the edge of the fabric. Begin about half an inch from the end of the piping,
hug the piping cord with the edge of the zipper foot, and begin to sew as close to the cord as possible.
When you reach a corner, stop with the needle in the down position and raise the foot.
Snip the seam allowance of the piping to about 2mm from the piping cord. Shift the piping to align it with the next edge of the fabric to be sewn. The snip you made will allow the piping to "turn the corner" neatly. Lower the foot and continue sewing all around the perimeter of the fabric piece.
Overlap the ends of the piping when you reach the place where you began stitching. That half-inch you left unsewn at the start in Step 1 will help you do this neatly. See this tutorial for how to overlap the ends.
Lay the other fabric piece (the lining), right side down, on the first piece. Pin in place. Using the zipper foot to hug the piping cord underneath, sew all around the perimeter of the fabric piece, leaving an opening for turning out. Sew as close to the piping cord as possible- you will not be able to see the cord but you can feel it underneath the fabric layer. In the photo below, the seam allowance is all irregular because I didn't bother to cut it precisely. Yours should look much better!
Notch all the corners of the seam allowance.
Turn right side out through the opening. Turn out the corners as sharply as you can, and press.
Fold a portion of the top over to form the flap. Remember to keep the layer with the hole (the lining) as the back of the pocket. Top stitch the flap down.
Note: This pocket was cut on the bias (i.e. stretchy in all directions as a result), so it got a little asymmetrical during the sewing process. A light fusible interfacing would have helped stabilize it.
Top-stitch the sides of the pocket to the garment. Because of the flap, you will not be able to sew all the way to the top edge of the pocket,
meaning that the top corners will pull away from the garment.
Stitch-in-the-ditch between the piping and the fabric in just that upper corner to secure it to the garment. The presser foot has been removed for clarity in this picture.
Now the top corners are securely attached to the garment.
and you can sew on a button if you wish. Note that the button is sewn only to the pocket, and not to the garment as well. If you had wanted a buttonhole, it should have been sewn before Step 6.
Here is a variation of the same pocket, with two differences:
1 The lining and outer fabrics are different, adding contrast when the flap is folded down.
2 The pocket is rounded and has no corners.
Store-bought piping is cut on the bias, so it hugs curves easily without your having to snip the seam allowance. If you make your own, and if it isn't cut on the bias, then snip every 1/4" along the seam allowance so it fans out as you sew it.
Here is another lined patch pocket made to impersonate an inset slash pocket. Only the edge of the opening is piped:
Attach the piping to just one edge, then stitch both layers of the pocket together, right sides touching. Leave open and unfinished, the sides that will get tucked into garment seams later.
Turn right side out and press.
Top-stitch along the edge of the pocket opening.
Then pin the pocket in place on the garment and top-stitch all around to attach.
Continue to assemble the garment, concealing the unfinished edges of the pockets within seams.
This tutorial has also been added to the pocket series here.