DIY Ultralight Backpack: My Search for a Perfect Pack

It’s the frame Seek Outside sells with all their packs.  Not separately listed on their site.  Not sure how keen they’ll be if Luke unleashes the floodgates of aftermarket requests. ;)

Thanks Dave, I figured as much.
I definitely like the looks of yours and Luke’s rather than the bolted flat bar that I found while searching.

Luke it might be helpful if you listed where your sourced you materials.

Luke, this article is great–thank you for all the detail of your thought process. Do you have any tips for measuring the torso length on this kind of build (to know where to sew on the upper shoulder strap attachments), since the hip belt is floating and the hip belt grommets make it somewhat adjustable? Are you measuring your torso length starting from the bottom seam, minus the seam allowance, up to between the fixed shoulder strap attachment webbing, or do you start at some point higher than that on the bottom? Or lining up the frame on the back panel pieces as best you can before they’re sewn, pulling the hip belt up to simulate the weight load on the frame and then measuring up from the center of the hip belt to determine where the center of the upper shoulder strap attachment should go?  I’m trying to figure out a way to do it that’s a little more exacting than just pure guessing/ trial and error. Thanks!