Spar End Fitting

[Daryl and Daryl]

I like this fitting and find it useful. You may too. It goes on the end of carbon fiber tubing….or any tubing for that matter.

Here's where you can buy them.

here

Here's a way that I have recently used them.

Additional Info

(1) The back pack frame in the photo has 4 of the fittings attached, one in each corner. The ones on the top corners allow me to attach the back and front bags of my backpack. The ones in the lower corners allow me to attach the backpack waist belt.

(2)The frame, with the 4 corner fittings, weighs about 1 3/4 ounces. Each of the 4 fittings weigh about 1/22nd of an ounce. I used the ones specifically sized for the Skyshark 400 spars.

(3) I glued the 4 fittings to the spar ends with super glue. They can also be held in place by adding a tight string between them, running from the top to the bottom of the spars on the outside of the spar.

[Daryl and Daryl]

When walking the forces from the pack and waist belt both push toward the mid points of the two vertical frame stays. So I don't have to worry about the end fitting coming off.

When I lift up the pack by the bag, (or upside down by the waist belt, however, it pulls upward on the fittings at the tops of the two vertical pack stays.

So I decided to test the holding power of the four super glued fittings on the two vertical stays. I simply hung each stay from a cord at the top and then hung a bucket with 40 lbs of lime from the bottom of each stay. I tested each stay separately, not at the same time.

Each stay, with fittings, passed the 40 lb test. I don't know the breaking point or pulling off point for the fittings but 40 lbs each is plenty for my needs.

[Jack Hoster]

I take it you use them for this:

Love to see more.

[Daryl and Daryl]

Jack,

"I take it you use them for this:"

Yes.

"Love to see more"

here

Daryl

[Jack Hoster]

Interesting.

How does it ride/carry/feel?

[Daryl and Daryl]

Jack,

Rides and feels great.

I've made one for my wife and one for a tall friend of mine. My wife gave up her old MSR pack and my friend gave up his ULA pack and both now use modfications of this myog design.

Pack fitting is tricky, however. It took years of trial and error for me to get where I am with this baby. I know it works for 3 of us but I really can't know if it would work for a person without them actually trying one.

Using a front bag requires some practice with it. Once learned, however, it is worth it in my opinion. I use mine every day to and from the gym and grocery store. I routinely carry 25-30 lbs of groceries home. The front bag allows me to walk comfortably without straining to lean forward or backward.

Daryl

[Coin Page]

Daryl

Is this the fitting with model number ending in "Shark 400" for Skyshark 400 spars?

How do you now attach the top straps, side straps, pack, and waist belt to the frame now that you no longer use the T's?

How are you attaching the cross piece now? Your earlier photos show the cross piece attached with T's.

The cross piece is now lower than the top of the frame where the front webbing comes off? Does this give the frame better support, or give a better angle for the front webbing to come off?

You posted a while back that the additional buckles on the front pack allow you to use it by itself as just a day pack. How do you rig this without the frame?

Have you ever tried an additional cross piece on the bottom of the frame?

I've been experimenting with your design for the last year or so. Thanks for all your posts and information. I tried a mock up frame last year with wooden dowels, but couldn't really get it to work. So, I stripped down an old Camp Trails frame and hip belt, and attached a homemade pack and front bag per your design. It's worked great for the last year. Total weight 3 lbs – not that bad for a full frame pack, padded hip belt, with no weight on the shoulders. The convenience of the front pack is lovely in and of itself. That it balances the back pack with no shoulder straps is marvelous.

I have the Skyshark 400 spars on hand now, and some webbing. I'll see what I can do to copy your frame and hip belt. Thus the questions above. First I'm going to try just the carbon fiber frame, and attach it to my traditional hip belt. (I recall you posting that getting a lightweight hip belt to work right is tricky – hard to keep it from kinking. I found this to be true using a soft webbing from the fabric store for my first trial.)

[Daryl and Daryl]

Coin,

I can only partially answer your questions because I'm relooking at every aspect of the pack in anticipation of making the next, lighter version on my way to the breaking point……which I haven't yet reached.

My strategy has been to make a version and use it every day going to the gym and grocery store (I'm retired) and backpacking with it as well. As I'm testing one pack I'm researching ways to make each component (frame, cross bar, waist belt, fabric, etc.) lighter and/or better. Many/most of the things I try don't work. Once a get a good set of things that do work, however, I make a new version and start testing it. I try to post things as I go along. Feels good to share and I get some good ideas and feedback from others.

Soooooo, keeping in mind that this is a moving target, here are my responses to your questions.

"Is this the fitting with model number ending in "Shark 400" for Skyshark 400 spars?"
yes

"How do you now attach the top straps, side straps, pack, and waist belt to the frame now that you no longer use the T's?"
I haven't abandoned the Ts and may go back to them. For the end fittings shown in this thread I have tied them on with cord and/or used zip ties. I drilled out the string holes in the end fittings so a zip tie would slip through easily. The 40 lb testing was done after I drilled out the holes. Home depot has plenty of zip ties with breaking strengths up to 75 lbs. Not real keen on any of my methods of attaching to the end fittings yet. They are lighter than those very heavy(joke) quarter ounce plumbing Ts, however, so they are worth a look. Plus they can be glued to the spars with super glue. Neither nylon nor polypro plumbing Ts glue very well with anything I've tried.

"How are you attaching the cross piece now? Your earlier photos show the cross piece attached with T's."
Ts are still my favorite. I've experimented with a half dozen lighter ways of doing it but none of them really click for me. The cross piece needs to be stiff but not very strong. It's primary purpose is to keep the top of the vertical spars from coming together. As one goes weaker, however, the primary risk of breakage is grabbing the cross piece as a handle to lift the pack. It is so handy it is hard to resist.

"The cross piece is now lower than the top of the frame where the front webbing comes off? Does this give the frame better support, or give a better angle for the front webbing to come off?"
I'm not sure of the answer to either of these questions. I experimented with the position of the cross bar for a different reason. My wife would like to try the front bag. She has a very straight back and a bar at the top of the frame might hit her head. (I have a curved back and it doesn't bother me. So I've been experimenting with ways to put the bar 2-3" lower so it crosses near the curve of her neck rather than the back of the head. My experience has been that the front bag webbing should connect to the top of the two vertical frame stays. For me, having the frame stay tops at about the same level as the tops of my ears works well. The front bag webbings then kiss but leave no weight on my shoulders on their way to the front bag.

"You posted a while back that the additional buckles on the front pack allow you to use it by itself as just a day pack. How do you rig this without the frame?"
I think I'll have to add a photo to make this clear but here are some words to get you started. I make the frontbag-to-spartop straps extra long. While hiking I use these straps as arm wrests. For use as a day pack I disconnect the male half of the buckles from the spar tops (quick release buckles) and connect them to the female buckle halves on the bottom corners of the front bag. I then have a day pack with 1/2" inch shoulder straps.

"Have you ever tried an additional cross piece on the bottom of the frame?"
Yes. Seems to add no benefit and unless it is curved it rubs against my lumbar area.

"I've been experimenting with your design for the last year or so. Thanks for all your posts and information. I tried a mock up frame last year with wooden dowels, but couldn't really get it to work. So, I stripped down an old Camp Trails frame and hip belt, and attached a homemade pack and front bag per your design."
That's pretty much how I started about 10-20 years ago. My goal was to get the comfort and carrying capacity of my 5 lb MSR pack without all the weight.

" It's worked great for the last year. Total weight 3 lbs – not that bad for a full frame pack, padded hip belt, with no weight on the shoulders."
I agree.

" The convenience of the front pack is lovely in and of itself. That it balances the back pack with no shoulder straps is marvelous."
I agree. It's hard to know the feeling without having experienced it.

"I have the Skyshark 400 spars on hand now, and some webbing. I'll see what I can do to copy your frame and hip belt. Thus the questions above. First I'm going to try just the carbon fiber frame, and attach it to my traditional hip belt."
That's what I did too. I think it is good to change only one component at a time on a pack that is working. Otherwise the variables can interact and leave one confused about what worked and what didn't. I changed several things at once just prior to a backpacking trip about 10 years ago. Nothing worked. The pack didn't even feel good at the end of the trip with no water or food in it.

"I recall you posting that getting a lightweight hip belt to work right is tricky – hard to keep it from kinking. I found this to be true using a soft webbing from the fabric store for my first trial."
The hip belt was the most challenging part and I left it til last. I think I have it licked now, however. I use Leno Loc Mesh (or the apparently unavailable Saran mesh). Thanks to Roger for steering me to the Leno Loc Mesh. A two inch wide good fitting belt with a fold-back-onto-itself velcro buckle comes in at less than 2 ounces and is as comfortable (for me) as the 8-12 ounce padded (Camptrails?) waist belt that was the last thing I give up on my road to lightweight insanity.

I'm pleased that you are working on this project. If I can get a few people up to speed on this project I'll soon be asking the questions.

Daryl

[Roger Caffin]

Hi Daryl

My packs are a bit similar to yours, with a very light tubular frame made from Easton arrow shafts and mesh sprung across the back.

> My experience has been that the front bag webbing should connect to the top of the
> two vertical frame stays.
Absolutely! ALL loads should connect directly to the verticals.
I tried (and tried and tried) to use one of the horizontals on a 2-month trip in Europe, and failed. The junctions simply could NOT take the load while walking. I modified the attachments one afternoon in the field using my small repair kit, and the mods lasted for the next few years.

Cheers

[Daryl and Daryl]

Roger,

"Absolutely! ALL loads should connect directly to the verticals"
Thanks for the confirmation.

"I tried (and tried and tried) to use one of the horizontals on a 2-month trip in Europe, and failed. The junctions simply could NOT take the load while walking. I modified the attachments one afternoon in the field using my small repair kit, and the mods lasted for the next few years."
Similar to my experience. That horizontal cross bar looks so inviting for hanging the pack bag. I have tried many times to use it too. Even when things hold together the back bag just doesn't drape correctly. I always end up going back to the verticals.

Daryl

[Roger Caffin]

Hi Daryl

> Thanks for the confirmation.
That's all right, I'll post my invoice shortly … :-)

Cheers

[Coin Page]

Daryl,

Thanks so much for your thoughtful and detailed feedback, and encouragement. I'll get to work and let you know how it goes.

[Daryl and Daryl]

I decided to go back to nylon plumbing Tees on the corners and wanted to re-use the vertical spars.

To remove the super glued end fittings from the spars I used a galvanized pipe just large enough to fit over the fittings. As I held the spars firmly on my workbench I slammed the end fittings with the pipe by repeatedly sliding it down the length of the spar. It took at least a half dozen hard blows to remove them.

No hardware was injured in the making of this post. The spars and end fittings can be reused.

I think I can vouch for the strength of the fittings and their holding power when super glued to the Skyshark 400 spar. I wouldn't hesitate to use them if you find a place for them in your projects.

[Daryl and Daryl]

Coin,

"You posted a while back that the additional buckles on the front pack allow you to use it by itself as just a day pack. How do you rig this without the frame?"

Here are couple photos to illustrate:

The front bag (aka the day pack) is a simple envelope shaped bag that is about 15" X 15" when laid flat,as in the photo. The flat photo shows the side of the bag that goes against the body when worn either as a front bag or day pack.

Front Bag-When worn as a front bag the long webbings with quick release adjustable buckles go from the top of the front bag to the top corners of the pack frame. Straps also come from the bottom corners of the pack frame and connect to the buckles shown with an X in the photo. The lower straps aren't in the photo because they are permanently attached to the bottom of the pack frame and connect to the front bag with quick connect adjustable buckles.

Day Pack-When worn as a day pack the long webbings are connected to the buckles shown with an X in the photo.

Actual Use-I rarely use the day pack conversion feature these days. I originally used it when I was carrying just a few items at camp because carrying just a few items in my full frame pack didn't work well. They jiggled around too much. I've since modified the frame pack design so it carries small loads better. The shape of the pack morphs as things are added to it. Here are photos showing how the shape of the frame pack changes as it goes from empty to full:

Here's a posting with more info:

here

Daryl

[Coin Page]

Thanks Daryl. I get it. In one of your early photos there was a 3rd set of buckles just below the top set, but facing down. I gather from this photo you don't put them on anymore and use just the two sets – top and bottom. Thanks again for posting this design. This is the design I used for my front bag – 15" x 15" seems just right. Anything I could possibly want access to during the day will fit inside.

[Daryl and Daryl]

Coin,

The third set of buckles is still there. I sometimes connect the straps from the frame bottoms to them. It gives a different feel to the front bag and allows it to hang away from my body a bit. See the buckles with the O on them, below:

You can easily try this without sewing the buckles on. Just slip them down the upper straps to the top edge of the front bag. They work fine this way.

I also have other buckles on the front bag that you can't see in the photo. I use them to hang my bear spray and monocular.

I'd like to answer a previous question differently. I had answered no and no. Upon thinking about it I really don't know the answers to your two questions so I edited the previous post. Here's what I'm talking about:

"The cross piece is now lower than the top of the frame where the front webbing comes off? Does this give the frame better support, or give a better angle for the front webbing to come off?"
I'm not sure of the answer to either of these questions. I experimented with the position of the cross bar for a different reason. My wife etc.

Daryl

[Author]

Posts