What does “do everything” mean? Dayhikes? Work/laptop? Commuting? Travel? Gym bag? Groceries?
And how much weight are you planning on carrying?
Keep in mind, every “feature” you tack on (load lifters, sternum strap, daisy chain, trekking pole loops, stuff pocket, hip belt,Ā removable hip belt, etc.) adds to complexity and therefore cost and construction time. Be warned… you might come out of COVID with a backpack buy also a grey beard! Welcome to BPL lol!
Opinion time:
Most people have a certain weight threshold that bothers them. And then there are those people who can carry 40+ lb on their shoulders only and not complain. I call them superhuman. My shoulder’s get tired after a 30 minutes of 10-15 lb on my shoulders only.
I feel (yeah… just a personal feeling/observation) that most daypacks don’t generally have or require load lifters, unless you’re looking at a framed pack like the Osprey Kestrel, or some other big manufacturer. I love load lifters… but idk how crucial they are for day hikes. I guess it depends on your weight you’re carrying and how comfortable/tolerable it is on your neck.
If it’s a flat aluminum bar, sure. If it doesn’t bend (and stay bent, but springs back) under you just gradually forcing the two ends together in compression, should be OK. I think a 1/2-inch x 1/8-inch flat bar (like what you have) is what a few manufacturers use. Should be ok for 20+ lb easy. I’m gonna guess though that that bar is not that long. My personal opinion is that load lifters work better if they’re up a little higher. But, while I’ve never been able to find it at Home Depot, I’ve found 1/8 x 1/2 x 36 aluminum flat bar at Lowes for a few dollars. Works great.
The reason I like a sternum strap is because it’s one more layer of adjustability, allowing you to move the shoulder straps in or out depending on your preference. This is crucial for me… I hate getting chaffed pits! Might be helpful with an MYOG pack… which you wouldn’t be able to “try out” until it’s completed. I tried to mimic the shoulder straps/fit of an existing backpack I have, and while good, it’s not quite the same.
The only concept I’ve mulled over regarding the laterally adjusting shoulder straps is using webbing and sliders (triglide, perhaps?) attached to the pack body, similar to how they have sternum straps you can adjust up and down. Or… I’m sure you can figure something out with enough Velcro :) However, I’d think that’s potentially weaker than just sewing it in. It doesn’t need to adjust laterally if you construct it to fit you well. I think that’s way more important. Doesn’t matter how cool it looks if it doesn’t fit you well… you won’t want to use it.
OWF Inc. has 1/4-inch, but regardless of you find it, it usually cost’s a buttload to ship from what I’ve seen. But I guess that’s all foam. Quest’s 3/8-inch is fairly cheap for me since I’m close :)
There are a bunch of cottage manufacturers that have backpacks that are good reference for getting an idea of what you like, what you don’t, and how to construct it in a simple manner.