Good Bye Spreader Bars (and plug for the new D4 Portaledge)

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Moof

Big Wall climber
Orygun
Apr 9, 2017 - 07:08pm PT
These corners were originally made for carbon fiber tubes, and I was paranoid about the ends splintering/crushing after abuse, so the recepticle is a full 1.5" deep, about 1/8" wall thickness. It should provide some of the rigidity Duece is getting from his curved corners. I have my corners on the end tubes instead of the side tubes, cuz I always have to learn the hard way... We'll see how that works out shortly, but it is how my carbon ledge is set up.

I honestly don't know whether male or female corners ultimately hold the best strength/rigitity/weight optimization. It is something I have pondered a few times to no avail.
Moof

Big Wall climber
Orygun
Apr 9, 2017 - 07:34pm PT
Loks like the fabric place sent me 2x the fly material. The roll was alarmingly heavy, but it looks like they sent me 12 yards instead of 12 half yard like I ordered. Bonus! Not sure what to use it for however.

I am planning to see if I can't add some pockets INSIDE the center fin between the two layers (mine is a 2 strap with a catenary in between, fabric weeve on the 45 for better force spreading). Need some place to stash crap, you know?
WBraun

climber
Apr 9, 2017 - 08:00pm PT
Looks good Moof.

With your new portaledge and your new valley giants you'll be the bomb ......
deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 9, 2017 - 08:52pm PT
Nice, Moof.

Another trick for tube cutting I recently rediscovered is using a step drill to do the initial deburring after using the tube cutter.

Just something like this--has the right taper, gets a nice initial inside debur.


Of course having a regular deburrer is key as well:


What kind of glue are you using for the aluminum? I have some concern about the expansion/contraction in colder temps, but would be interested in hearing more about gluing vs. riveting.
Moof

Big Wall climber
Orygun
Apr 10, 2017 - 06:40am PT
Same Hysol 9340 I had leftover from my carbon fiber project, been storing it in the freezer. A aircraft home builder recommended it some years back. For glueing up Al to Al the TCE mismatch is essentially zero.

I'll have to get a proper deburr tool, I have been just carefully using a utility knife. No bueno. Never thought to use one of those step drills!
deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 10, 2017 - 02:26pm PT
Slow speed is the key for the step drill, no more than 500rpm. There are speciality tools for chamfer and deburring tube edges, but very expensive. Step drills are cheap and readily disposable when they get blunt.

For a non specialty tool system for the outside edges of tubes that get inserted into another tube in the design, I use a belt sander and hold the tubes while spinning them and change the angle to get a nice rounded edge. Then about a minute or two steel wool polish by hand.

Having an air blower, even just a can of compressed air, is also a key tool for making frames, as even the most invisible spec of aluminum shaving can cause problems in the joints. Or you could use some sort of cloth to push all the way through the tubes to ensure fully clean.
BLUEBLOCR

Social climber
joshua tree
Apr 10, 2017 - 03:03pm PT
Moof👌👍
Moof

Big Wall climber
Orygun
Apr 10, 2017 - 04:54pm PT
Werner,

Goal is to be the best dressed Toprope Tough Guy in the valley!

I should drag my junk show up Royal Arches and get the first 8 day ascent. Unless Chongo already beat me to it?

[Click to View YouTube Video]

Edit: Hey, the narrator at 0:12 looks awfully similarly to my actual partner...
Moof

Big Wall climber
Orygun
Apr 11, 2017 - 04:45pm PT
As previously stated, I have to do things the hard way, and can't always let myself learn wisdom for others until I have thrashed through the briar patch myself.

So back to suspension fins, and catenaries. I can't quite let that one go yet.

Guess what? Mistake #1 before I got re-started.

Not a catenary! Using the webbing for the suspension fin is akin to a suspension bridge, with equal loading per unit horizonal length. A catenary is the shape for equal weight per linear unit along the length of the curve (i.e. natural curve of a chain vs. Golden Gate bridge).

So the correct shape to start with is a parabola. Who knew?!

Next, the loading is at ~22.5 degrees to the bed, so really you have 2 back to back parabolas that are then rotated by 22.5 degrees to make everything make sense, so you get an ideal fin shape for equal weight distribution along the length of the bed like this (part below 0 would be trimmed off):
Actually getting the suspension bridge effect requires the weave to be rotated by 22.5 degree when cutting the shape. As Duece noted, actually getting webbing to follow the shape is a different story, but I had to finish scratching the itch from a couple weeks back.

Next up: My center fin will really be an overlapped cable stayed bridge prototype, not a catenary or parabola. Stay tuned...
deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 13, 2017 - 10:46pm PT
Looks really nice, Moof. Are you going for fin supports for your ledge?
hobo_dan

Social climber
Minnesota
Apr 14, 2017 - 05:07am PT
In my last year of teaching I've been asked to do a basic course in Physics- not certified for it, but riding a variance.
John, I'm enjoying the technical arguments and your basis for design change-- you do a nice job of zeroing in on the parts of the equations that matter--Your discussion on tube length was well done. This is great nerd entertainment.
Moof

Big Wall climber
Orygun
Apr 14, 2017 - 02:30pm PT
Duece,

Yep, I am planning on shamelessly being inspired by your D4 design and use 4 side fins, but I am adding my own flair and quirks along the way rather than a full-on knock off. I have more fun being inspired rather than copying. Hence it is a Hobby Ledge, not anything beyond.

Your much earlier post for the block corner design sketch was my inspiration and starting point. I re-calculated everything based on my own existing corners, and the desire to put those on the end poles instead of on the side poles. I use 4" of pole overlap on the side poles, and 6" end joiners (3" overlap). Putting the corners on the ends allows for a large overlap, as long as I can get the side poles into the corners). Swapping the corners around lets me use two 7' pieces of bungie cord instead of 22' of bungie for a small weight savings, just stopper knots in the corners needed.

A few things on Hobby Ledge different, like a 8:1 bed tensioner using a zig-zagged piece of 3/4" thin webbing through D-rings. I am excessively obsessed with spreading tension out and other pedantic details (my inner engineer is mad about how much my inner perfectionist is missing the forest for the trees).

I am also only putting the tensioner at one end. The end tubes will stay inside the fabric tube on the other and just get folded up. I am just about done with sewing the tensioner end of the bed and will post pics soon. I am only getting 1-2 hours every 2-3 days to work on this project.

Side pole internal double butting got all glued up last night. It was shocking how much the dry fit internal reinforcement stiffened up the side pole flex, bravo sir! I was able to play with a nice A/B comparison, and wow does it work as advertised. I manged not to order 1"x0.058" material for the 4 bits of corner double butting, which is a bummer, since otherwise the frame is now done. Argh. I hate wasting money on even more shipping.

More updates and pics will show up this weekend when I should be able to get 4-5 hours during kiddo's nap times. I am likely not to finish my fly in time for our May trip, but I have an ACE and 2 A5 flys that should fit fine, but I'd rather use my own if I can.

deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 19, 2017 - 05:14pm PT
First Video Review!

https://www.instagram.com/p/BTDM1heloNr/

Thanks Acro John!

he also writes:
The main points that stood out for me were:
1. Super small size and weight packed w/ fly
2.how the long sides almost pop together on their own, and the way you put end pole stows so they don't just flop around.
3. The ridiculously easy connection of end poles.
4. The 4 part suspension. Quick and stable!
5. The haul bag side zipper with interior pocket for pole... this just blew me away! I had Rebecca get it out and she has never set up a ledge before, and watching how she was able to intuitively unzip and take it out was awesome! No other major ledge out there right now sets up with such ease.
deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 22, 2017 - 03:19am PT
Perhaps this link is better!
https://www.facebook.com/bigwallgear/videos/427919084252091
'Pass the Pitons' Pete

Big Wall climber
like Ontario, Canada, eh?
Apr 22, 2017 - 04:53am PT
^^ Is that "my" prototype, John?

"and watching how she was able to intuitively unzip and take it out was awesome!"

There has never been anything "intuitive" about setting up a portaledge! It has always been a perplexing struggle .... at least up until now. ;)
walmongr

Big Wall climber
Mesa AZ
Apr 22, 2017 - 08:32am PT
I rented an A5 double from Babbitt's in Flagstaff in the mid 90's, for our first wall (prodigal sun). We came back from that trip and bought one! Still have it and use it to this day I am sure this new one will be awesome with 20 some years of material advancement can't wait!!!
deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 22, 2017 - 11:34am PT
Yep, Pete, that's the one (prototype #3) earmarked for you, same one I used on Ozymandias last month. Still has an older version of the fly, though, good material and bomber, but we've since refined the pattern and added the door.

I just sent another demo (prototype #2, which was used in the Tarkine tree protests) to the USA with a friend who is heading to Zion, and I plan to match that one with a new fly as i hacked up its original fly as I am wont to do when I am in a creative mode (when I reinvented the Portaledge door system), and ideally we will try to get you a new fly with the door too, but right now we are also getting a few prototypes out the door for Twid Turner (proto#4) and Mike Libecki (proto #6 and #7) for their upcoming expeditions (plus we sent Marek who is still in Baffin a new fly last month).

Getting poised for our Kickstarter production...

Tom

Big Wall climber
San Luis Obispo CA
Apr 22, 2017 - 07:57pm PT
It's always nice to see that people are trying new things, and are not dependent on the big companies to decide how things are done.


PTPP's comment above about making sure the suspension straps are long enough is very germane. Sometimes, you will want to hang the ledge out from the wall, and not against it. For me, that was always the best configuration, because having my feet to the wall, and my head out in space, gave me the best view of the moonlit wall.

deuce4

climber
Hobart, Australia
Topic Author's Reply - Apr 23, 2017 - 01:07am PT
Pretty much all innovations come from the small companies, Think Bibler tent, small cams, lightweight packs, the list goes on.

Big companies revise and refine others' ideas, in general. They're too busy looking what the other companies are doing to truly innovate.

nah000

climber
no/w/here
Apr 23, 2017 - 01:24am PT
^^^^

they don't call it the bleeding edge for nothing...

that said two significant exceptions that come to mind are petzl and arc'teryx...

so not entirely a rule either.
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