I love my Patagonia computer backpack which is over 10 years old. Patagonia is great about repairing things and when I lost the one of the sternum strap sides 5 years ago, they sent me a free set. When I lost another one recently, customer service again was very helpful and ordered a replacement for me. Unfortunately, Patagonia no longer stocks that part and so I created my own replacement.
The clip slides onto a section of the shoulder strap and has ¾" polypropylene webbing (light or regular strength - NOT heavy duty) that connects to the the regular male and female clips. Consider using one of the other clips that you don't use like the belt strap. I have designed a compatible 3d printable male clip in PETG and am working on the design for the female clip.
The part is designed in 2 pieces to optimize the print for strength and ease of printing. The slide clip has notches and ridges to keep it together without glue. You will need a decent bit of force to assemble the slide clip. I recommend using channel lock pliers to assemble (see photos above)
Use a sewing machine to duplicate the way the other male clips are attached.
I've used my replaced sternum strap for over two weeks and it has worked perfectly!
The author marked this model as their own original creation.