Jetted/ Welt pockets are a tailoring staple. There are 2 places you are most likely to see a jetted pocket.
On the back of trousers/ shorts and on jackets (normally with a flap incorporated into the sewing).
Next time you make a pair of trousers or pants, incorporate a jetted pocket in the back and take your sewing from homemade to handmade.
Below is the technique that we use in the shop for easy jetted pockets, we have tried other ways, but this is the easiest way we have found.
1. Mark where you are going to place the pocket is going to be. Normally we would place the middle of the pocket at the base of the dart at the back of the trousers. This is theoretically the center point for that leg, so the pocket should sit nicely.
2. Decide how big the pocket is going to be, I am making a 5 inch wide pocket opening today. Using tailors chalk draw a straight line that is 6 inches long, with the middle on the base of the sewn dart.
3. Cut pipping strips, 1 inch wide and 7 inches long
4. Lay one of the strips next to the marked line.
5. Select a locking stitch and sew a 1/4″ seam along the marked line. Start and finish precisely from the marked lines.
6. Repeat for the remaining stip.
7. Turn to the wrong side and mark a line about 2cm from the ends of the stitching and then mark a straight line as shown. Then mark from the middle line to the end of the sewn seam.
8. Clip the middle line, then clip the diagonal line to the end of the seam.
9. Pull one of the piping strips through and press flat.
10. Fold the piping strip so that it fills half of the hole, and press.
11. Repeat for the remaining piping strip.
12. Stitch in the ditch, along both piping strips to secure the piping.
13. Lay a pocket piece across the lower piping strip and stitch in the ditch to attach the pocket piece.
14. Work the buttonhole on the lower portion of the pocket.
15. Lay the remaining pocket piece across the upper piping strip and ditch stitch to attach the pocket piece.
16. Join the 2 pocket pieces.
17. Lay the piece face up and fold back the top layer of fabric to the start of the piping.
You should see a small triangle of fabric, from where we clipped the pocket. Sew this to the 2 piping strips.