My son wears a Medtronic 522 insulin pump, and to fit that pump I make a pocket that is about 4.5 in tall and 3.5 in wide. I sew the pocket onto the back of an undershirt because he was only 1 when he started on the pump and I did not want him to push any buttons. He is now 4 and we still use this method because it works well for us. Sometimes he wears his pump in his pants pocket, but having it in his shirt is still easier because he doesn’t get tangled in the tubing.
I don’t have step by step photos right now, but the next time I sew some pump pockets I will update with more photos.
1. Cut two rectangles: one 6 in x 4 in and one 5 in x 4 in.
2. Place the rectangles on top of one another lining up one of the short sides. They are the same width so those sides line up, but since they are different lengths only one of the short sides will line up.
3. Using a 1/2 ” seam allowance, sew along the matched short side, leaving an opening for turning in the middle. In other words, sew from the outside edges toward the center, but do not stitch the center closed. I usually leave about 1 in open in the center.
4. Align the other short sides. This will make a bubble because the rectangles are different lengths. Flatten the fabric so that the short side seam is not at the edge of the rectangle anymore. The large rectangle now folds over and the seam connecting the two is about an inch from the edge. Sew the other 3 sides closed.
5. Turn the pocket right side out through the opening you left in the first seam.
6. Sew a piece of hook and loop tape (Velcro) to the pocket between the short folded edge and the first seam.
7. Decide where you want the pocket on the shirt and sew the other piece of hook and loop tape to the shirt. I have found that if the top of the pocket is at about the bottom of the arm holes it works best. Placing the pocket too low on the shirt makes it pull and stretch more.
8. Stick the pocket to the shirt with the hook and loop tape. Topstitch the pocket in place, again with about a 1/4 in seam allowance. Begin and end the stitching about 2/3 of the way down the hook and loop tape. If you stitch the pocket all the way to the top on the long sides it is hard to get the pump in and out. The hook and loop tape will hold the pocket closed so the topstitching is not needed at the very top.