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splish


Jul 28, 2012, 11:30 PM
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JimTitt wrote:
Perhaps gunkiemike was making fun at your expense as the UIAA do not drop-test slings.

Yep, you are right. I am definately the idiot here.
I should have said pull testing.

I am sorry Mike. I know I am going to pay for this.

But hey, could be worse. I could have been the guy climbing in the zig zag stitch that supports 85Lbs...


JimTitt


Jul 29, 2012, 3:37 AM
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Re: [splish] Sewing your own slings [In reply to]
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I just thought I ought to correct you for the benefit of future readers in 2020.


wivanoff


Jul 29, 2012, 5:33 AM
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splish wrote:
Lift the engine, then I will be impressed.

I used to sew my own slings BITD (1970s). Not because I was cheap, but because sewn climbing slings just weren't available. Most people just tied slings out of 1" tubular webbing with a water knot.

"Off Belay" magazine had an article about sewing your own slings. They showed stitching patterns (multiple rows parallel to the length of the sling), type of thread, stitches per inch, length of splice, etc. (edit: looks like the same article was also published by Cal Magnussen here http://www.caves.org/...ical/nhback/NH03.pdf)

I decided to try that. To see how well I did, I tested one of my sewn splices like this: I used two lengths of webbing. First ends were stitched, second ends were tied with a water knot. I attached the slings between the trailer hitches of two trucks with some steel cable for slack. Used 1/2" steel quick links and Bonatti "D" carabiners. Drove/rolled one truck away to see what would happen.

First test, the water knot broke inside the knot. I retied it. Second test, the water knot broke inside the knot. I retied it. Third test the Bonatti carabiner snapped. After that, I decided my stitching was "strong enough". True, it was a very small statistical sample, but I was pretty confident with what I saw.

Interesting experiment and I used those homemade sewn slings for a while. But, I've been buying sewn slings since they became widely available and it was no longer worth my time to sew.


(This post was edited by wivanoff on Jul 29, 2012, 11:15 AM)


splish


Jul 29, 2012, 8:05 AM
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JimTitt wrote:
I just thought I ought to correct you for the benefit of future readers in 2020.

No problem Jim. I was definately wrong.

I like your style. You didn't resort to insults, name calling or swearing. You simply sat back, let me make myself look stupid and simply pointed it out with a quick bit of wit at the end.
It shows class and intelligence. Kudos!
I have no problem being the butt of the joke when I made the mistake.


crasic


Jul 29, 2012, 9:52 AM
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JimTitt wrote:
Perhaps gunkiemike was making fun at your expense as the UIAA do not drop-test slings.

Indeed, slings aren't dynamic elements like rope, they don't get drop tested because in reality they shouldn't be dropped on without a dynamic element. And basically any static drop test will only be useful if you have a weight cell to measure the load before breakage.

FF1 (80kg) on double length dyneema will snap it half the time, FF2 on single or double length dyneema will snap it guaranteed. Assuming a direct fall on a static anchor with no dynamic element. Nylons fairs a little better. If op doesn't have a load cell, him dropping a weight on it would tell him no information as even commercial slings are liable to snap.

linky


JimTitt


Jul 29, 2012, 10:58 AM
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Im English, we are brought up like that!

And Ive a dog and recalcitrant machines to insult and shout abuse at, they love it.


splish


Jul 29, 2012, 6:07 PM
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crasic wrote:
JimTitt wrote:
Perhaps gunkiemike was making fun at your expense as the UIAA do not drop-test slings.

Indeed, slings aren't dynamic elements like rope, they don't get drop tested because in reality they shouldn't be dropped on without a dynamic element. And basically any static drop test will only be useful if you have a weight cell to measure the load before breakage.

FF1 (80kg) on double length dyneema will snap it half the time, FF2 on single or double length dyneema will snap it guaranteed. Assuming a direct fall on a static anchor with no dynamic element. Nylons fairs a little better. If op doesn't have a load cell, him dropping a weight on it would tell him no information as even commercial slings are liable to snap.

linky

Yeah, I know. I didn't mean to say drop test, when I wrote that I was just not thinking about what I was typing. I should have said pull test, but was thinking of drop test for some reason.
Thanks for the link, some things I knew, but the refresher was good, and some things I learned.


(This post was edited by splish on Jul 29, 2012, 6:09 PM)


splish


Jul 29, 2012, 6:37 PM
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Re: [gthomann] Sewing your own slings [In reply to]
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In the mid 90's I was also curious about sewing slings. I did try it, but never had any intention of ever climbing on them.
I had sewn 3 slings, all roughly the same length, with a 5" overlap and a very simple pattern.
I don't know anything about threads and such, so I went to Fabricland, I showed the woman the webbing, and explained the purpose of it.
She sold me some higher end nylon thread and a proper needle she said would not tear the fabric, but instead separate the fibers allowing the thread to pass through without damaging the webbing.

Although I never climbed on them, I did try some very simple tests on them. Using the crane in the shop, I lifted various tools, starting with a Planer/Jointer that weighs in at 3500 lbs and working my way various larger tools till I reached the largest one we have in the shop that weighs in at 6745lbs.
The first sling broke lifting a 14" table saw with a net weight of 5600Lbs, the second sling broke when I lifted the same table saw with 600 lbs of plate steel on it. The third sling never broke and I didn't have anything larger to lift.
I left the sling in the work shop, and my father stole it and has been using it for various construction site needs since. The most impressive, removing a large tree stump. We were trying to pull in out using chains, but didn't have enough chain. First I used a piece of Blue Water 11mm Static line I had that had been retired, but it broke fairly easily. So we had the sling in the work van, and decided it was worth a go. We wrapped the stump in chain, a shackle connected the chain to the webbing, and another shackle from the webbing to the bob cat. I had tied a water knot in each end, so that may have helped some as the solid webbing may have took more of the force than the side that was sewn. We yanked and yanked, the sump did not move. We then resorted to putting slack in the line and then gunning it, putting a massive shock load on the whole system. After about 7 pulls like that, the stump came loose and we were able to remove it.
On the way home from work today, I stopped in to visit my parents, and because of this post, thought of that. Turns out my father still has the sling, and uses it from time to time for little tasks. Here are some images...







Unfortunately, I don't have access to a proper load cell, but I tell you, theis thing has stood up to some beatings. I would love to know what it would be rated at.


(This post was edited by splish on Jul 29, 2012, 9:05 PM)


gthomann


Jul 30, 2012, 4:58 AM
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Thats really impressive, especially with nylon thread, which is not all that strong. you must have done a really good stitching job. the woman at the sewing shop probably gave you a rounded point needle. I have just been using a universal needle, a rounded point would probably be better. I have sewed a few more slings (and loops at the ends of webbing) and use them when top roping, which puts little stress on them. I always show the other climbers what I am doing and give them the chance to opt out. But they are always comfortable with the slings, they know I am a crazy engineer.


dynosore


Jul 30, 2012, 8:33 AM
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splish wrote:
Rudmin wrote:
spikeddem wrote:
Gthomann, you keep saying the forces in a TR setup aren't much. I'm curious about the numbers you have for that. What forces have you observed?

I'd also be a bit surprised if it took a thousand pounds of force to lift the tail of a truck off the ground. Maybe if it was a pretty big truck with entirely too much junk in its trunk.

That truck probably weighs around 5000 lbs. If the centre of gravity was halfway between the front wheel and the hitch, he would be pulling up 2500 lbs. Since it's probably forward of that, 1000 lbs sounds like a very reasonable conservative estimate.

I have a full size SUV, with straight axles, and it doesn't weight 5000 lbs. The weight of any vehicle is on the door. The truck has no weight in the back. In high school, me and 3 other guys used to lift the back of Jeff's truck off the ground and turn it sideways in the parking spot. The back of a truck is ridiculously light!!!
Lift the engine, then I will be impressed. But I don't understand why this guy doesn't test it the same way UIAA does, put a wieght on it and drop it! find a porch or balcony or something. And a sand bag or some dumb bell weights!

Again, a full size pickup has a weight distribution around 55/45 front/rear, depending on box length, 2wd or 4wd, etc. Three of you picked up 2000 lbs or more?

What "full size" SUV do you have that weighs less than 5k pounds? A Tahoe, Suburban, or Expedition weighs between 5200-6500 lbs depending on the model. What do you drive?


billcoe_


Jul 30, 2012, 1:04 PM
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jt512 wrote:
The problem is, as research has shown, people who don't know what they are doing, don't know that they don't know what they are doing.

Jay


This is the only thing any of us really needs to read here, and it should be required reading. When teaching others climbing skills, I always emphasize repeatedly that they will not be aware of the things they don't know, and that lack of knowledge will and does often lead to a tragedy that totally blind sides them. 5 star link and post Jay.


splish


Jul 30, 2012, 6:44 PM
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dynosore wrote:
splish wrote:
Rudmin wrote:
spikeddem wrote:
Gthomann, you keep saying the forces in a TR setup aren't much. I'm curious about the numbers you have for that. What forces have you observed?

I'd also be a bit surprised if it took a thousand pounds of force to lift the tail of a truck off the ground. Maybe if it was a pretty big truck with entirely too much junk in its trunk.

That truck probably weighs around 5000 lbs. If the centre of gravity was halfway between the front wheel and the hitch, he would be pulling up 2500 lbs. Since it's probably forward of that, 1000 lbs sounds like a very reasonable conservative estimate.

I have a full size SUV, with straight axles, and it doesn't weight 5000 lbs. The weight of any vehicle is on the door. The truck has no weight in the back. In high school, me and 3 other guys used to lift the back of Jeff's truck off the ground and turn it sideways in the parking spot. The back of a truck is ridiculously light!!!
Lift the engine, then I will be impressed. But I don't understand why this guy doesn't test it the same way UIAA does, put a wieght on it and drop it! find a porch or balcony or something. And a sand bag or some dumb bell weights!

Again, a full size pickup has a weight distribution around 55/45 front/rear, depending on box length, 2wd or 4wd, etc. Three of you picked up 2000 lbs or more?

What "full size" SUV do you have that weighs less than 5k pounds? A Tahoe, Suburban, or Expedition weighs between 5200-6500 lbs depending on the model. What do you drive?

I have a 2004 Nissan Pathfinder Chinook. Added equipment includes 8' of 1/4" steel skid plates, ARB Winch Mount 1/4" steel bumper, snorkel assembly, dual battery, various off road lights and a winch. Lat time I went through a scale, it weighed in a 2404 KG. And that is with 2 full grown adults sitting inside. Just over 5000 Lbs, so the stock Pathy weighs much less I assure you.
I just looked up a few dodge trucks on Google, and they all do weight over 5000 lbs, but in the back end the only weight is the box, the back half of the frame, the drive shaft and the rear axle assembly. I am not sure of the exact weight distribution, But I wouldn't think it to be the the 55/45 that you stated, I think it would be much less.
As for the truck we used to life in high school, it was a 1983 GMC S15, which is smaller than the current Canyon. A very small truck, and the back end was incredibly light. We would kind of bounce it until the tires left the ground, and move it a few inches at a time until we turned it sideways across 2 parking spots with a car immediately in front and behind so he could not leave until those cars were gone.
My point is, lifting the rear end of a truck off the ground with a sling proves little when it comes to the forces involved in climbing.
Also, looking at the photo of the lifted truck. They used a small hand operated hydraulic crane rated to 4000 lbs and the boom is not showing any signs of deflection. Having used these devices many times, I can tell you, when you lift close to the rated weight of the device, there is at least an inch and a half or more of deflection in the boom.
Also, if you click on the photo and blow it up to full size, you can clearly see that only one rear tire is approx. 3" off the ground while the driver side tire is still firmly planted on the concrete. The chain that they used to wrap the bumper and lift from looks to be a much smaller size as well, not rated for heavy lifting. Much smaller than tow chains. This is really not a very impressive lift, nor do I think that this experiment would prove his stitching to be climbing worthy.


(This post was edited by splish on Jul 30, 2012, 6:53 PM)


vinnie83


Jul 31, 2012, 10:09 PM
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gthomann wrote:
nylon thread, which is not all that strong

I've got to ask, what are you using that is so superior to nylon and just how strong is it?

I was under the impression that nylon bonded thread is pretty much the standard when sewing just about any safety related gear out of nylon, but maybe that's just how things were done at the place I used to sew harnesses.

In reply to:
I am a crazy engineer.

You maybe crazy, but you're definitely not an engineer.


splish


Aug 1, 2012, 8:30 PM
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gthomann wrote:
Thats really impressive, especially with nylon thread, which is not all that strong. you must have done a really good stitching job. the woman at the sewing shop probably gave you a rounded point needle. I have just been using a universal needle, a rounded point would probably be better. I have sewed a few more slings (and loops at the ends of webbing) and use them when top roping, which puts little stress on them. I always show the other climbers what I am doing and give them the chance to opt out. But they are always comfortable with the slings, they know I am a crazy engineer.

Ok, listen to me, and listen very carefully!!!
You keep insisting there is little force on a top rope anchor. This is simply not true.
Just close your eyes and imagine this scenario.
Your climber is climbing at a decent pace. It's a simple 5.7. You get distracted for a single moment, someone talks to you, or tries to point out another climb. You don't pull in all the slack right away, and the climber has moved up 3 feet. Just as you are turning back to spot your climber, he/she fall. 3 feet of slack in the system, she falls a total of 3 feet, plus you get lifted slightly off the ground, a 5' fall plus the combined weight of yourself and the climber. How are your slings going to hold up then? Are you really willing to risk your climbers life on it?
On top of it all, reading this post is very scary. You really have no concept of climbing forces and such, which tells me you really have no concept of how to set up anchors and such.
I very highly suggest you take a top rope anchor course and speak to some professionals about your slings. Please, this is not something to take lightly!!!


jt512


Aug 1, 2012, 9:19 PM
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JimTitt wrote:
I just thought I ought to correct you for the benefit of future readers in 2020.

This post is genius.


curt


Aug 2, 2012, 8:14 AM
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splish wrote:
gthomann wrote:
Thats really impressive, especially with nylon thread, which is not all that strong. you must have done a really good stitching job. the woman at the sewing shop probably gave you a rounded point needle. I have just been using a universal needle, a rounded point would probably be better. I have sewed a few more slings (and loops at the ends of webbing) and use them when top roping, which puts little stress on them. I always show the other climbers what I am doing and give them the chance to opt out. But they are always comfortable with the slings, they know I am a crazy engineer.

Ok, listen to me, and listen very carefully!!!
You keep insisting there is little force on a top rope anchor. This is simply not true.
Just close your eyes and imagine this scenario.
Your climber is climbing at a decent pace. It's a simple 5.7. You get distracted for a single moment, someone talks to you, or tries to point out another climb. You don't pull in all the slack right away, and the climber has moved up 3 feet. Just as you are turning back to spot your climber, he/she fall. 3 feet of slack in the system, she falls a total of 3 feet, plus you get lifted slightly off the ground, a 5' fall plus the combined weight of yourself and the climber. How are your slings going to hold up then? Are you really willing to risk your climbers life on it?
On top of it all, reading this post is very scary. You really have no concept of climbing forces and such, which tells me you really have no concept of how to set up anchors and such.
I very highly suggest you take a top rope anchor course and speak to some professionals about your slings. Please, this is not something to take lightly!!!

You should probably give your scenario a little more thought. It's impossible to generate a FF=1 fall top roping and your scenario would likely be far less severe. Let's assume a 50ft climb is being top roped. That means there is initially 100ft of rope running from the climber up to the anchor and back down to the belayer. Suppose the climber gets half way to the anchor (he's 25 feet up) and then falls, with the 3 feet of slack you mention. The resulting fall is only FF=.04.

Curt


Partner cracklover


Aug 2, 2012, 9:21 AM
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curt wrote:
splish wrote:
gthomann wrote:
Thats really impressive, especially with nylon thread, which is not all that strong. you must have done a really good stitching job. the woman at the sewing shop probably gave you a rounded point needle. I have just been using a universal needle, a rounded point would probably be better. I have sewed a few more slings (and loops at the ends of webbing) and use them when top roping, which puts little stress on them. I always show the other climbers what I am doing and give them the chance to opt out. But they are always comfortable with the slings, they know I am a crazy engineer.

Ok, listen to me, and listen very carefully!!!
You keep insisting there is little force on a top rope anchor. This is simply not true.
Just close your eyes and imagine this scenario.
Your climber is climbing at a decent pace. It's a simple 5.7. You get distracted for a single moment, someone talks to you, or tries to point out another climb. You don't pull in all the slack right away, and the climber has moved up 3 feet. Just as you are turning back to spot your climber, he/she fall. 3 feet of slack in the system, she falls a total of 3 feet, plus you get lifted slightly off the ground, a 5' fall plus the combined weight of yourself and the climber. How are your slings going to hold up then? Are you really willing to risk your climbers life on it?
On top of it all, reading this post is very scary. You really have no concept of climbing forces and such, which tells me you really have no concept of how to set up anchors and such.
I very highly suggest you take a top rope anchor course and speak to some professionals about your slings. Please, this is not something to take lightly!!!

You should probably give your scenario a little more thought. It's impossible to generate a FF=1 fall top roping and your scenario would likely be far less severe. Let's assume a 50ft climb is being top roped. That means there is initially 100ft of rope running from the climber up to the anchor and back down to the belayer. Suppose the climber gets half way to the anchor (he's 25 feet up) and then falls, with the 3 feet of slack you mention. The resulting fall is only FF=.04.

Curt

Don't shut him down, Curt, or he'll leave this one and find another five year old thread to resurrect so he can spew half-baked verbal diarrhea all over that too.

Sorry, splish, do go on. I believe you were sharing something brilliant and revolutionary?

GO


crasic


Aug 2, 2012, 10:33 AM
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curt wrote:
You should probably give your scenario a little more thought. It's impossible to generate a FF=1 fall top roping and your scenario would likely be far less severe. Let's assume a 50ft climb is being top roped. That means there is initially 100ft of rope running from the climber up to the anchor and back down to the belayer. Suppose the climber gets half way to the anchor (he's 25 feet up) and then falls, with the 3 feet of slack you mention. The resulting fall is only FF=.04.

Curt


Worst case scenario fall, where the belayer is asleep and takes in no slack and climber falls from the very top (assuming they can fall past the belayer without decking) is a factor 0.5, best case scenario (take and rest) is a factor 0, all top-rope falls are between the two.

When you calculate the fall impact load factor (F/W) for a 50ft climb, this corresponds to a range between 2.0 and 6.0. Which is then, at the extreme, doubled at the anchor (in the implausible scenario of it being an ideal pulley instead of a biner up top), in reality its more like 1.5x at the anchor due to biner friction.

So the worst case possible fall possible on top rope (again, almost impossible, a full route length worth of slack), will load the anchor 9x the weight of the climber, so around 1600lb (7KN) for a 180lb climber. Thats nothing to scoff at, but thats better than a fall from a short leader runout. And that is not including rope slip and a myriad of other factors that lengthen the fall and reduce the actual force on the anchor, His flying belayer will actually reduce the impact on the anchor then if he was anchored to an immovable boulder.

Slish's factor 0.04 fall will, in all actuality generate a fall impact factor of ~2.2, so approximated a 3-4x impact on the anchor. Meaning 600-800lb (3-4KN). Depending on your POV, thats either really small (in relative climbing terms) or pretty big (in absolute terms for home-stitched soft-goods), however its not at all bigger than that seen by a factor 0 fall, and the marginal difference between a factor 0 and 0.04 fall can be completely hidden by natural variations in friction at the top biner (e.g. a 0.04 fall on a more sticky or rough section of rope will generate less force than a FF0 fall on a section thats been glazed from a fast rappel)


curt


Aug 2, 2012, 11:30 AM
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crasic wrote:
curt wrote:
You should probably give your scenario a little more thought. It's impossible to generate a FF=1 fall top roping and your scenario would likely be far less severe. Let's assume a 50ft climb is being top roped. That means there is initially 100ft of rope running from the climber up to the anchor and back down to the belayer. Suppose the climber gets half way to the anchor (he's 25 feet up) and then falls, with the 3 feet of slack you mention. The resulting fall is only FF=.04.

Curt


Slish's factor 0.04 fall will, in all actuality generate a fall impact factor of ~2.2, so approximated a 3-4x impact on the anchor. Meaning 600-800lb (3-4KN). Depending on your POV, thats either really small (in relative climbing terms) or pretty big (in absolute terms for home-stitched soft-goods)...

That's probably a reasonable estimate. In any event, based on the ad hoc testing by wivanoff and splish himself on their own home-sewn slings and the data presented here:

http://www.caves.org/...ical/nhback/NH03.pdf

I probably wouldn't be too worried about using similar slings in a top rope anchor--particularly because I wouldn't construct the anchor to rely on a single sling anyway.

Curt


JimTitt


Aug 2, 2012, 11:58 AM
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jt512 wrote:
JimTitt wrote:
I just thought I ought to correct you for the benefit of future readers in 2020.

This post is genius.

Well thanks, nice to be appreciated!


wivanoff


Aug 2, 2012, 12:25 PM
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Re: [curt] Sewing your own slings [In reply to]
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curt wrote:

That's probably a reasonable estimate. In any event, based on the ad hoc testing by wivanoff and splish himself on their own home-sewn slings and the data presented here:

http://www.caves.org/...ical/nhback/NH03.pdf

I probably wouldn't be too worried about using similar slings in a top rope anchor--particularly because I wouldn't construct the anchor to rely on a single sling anyway.

Curt

I've taken lead falls on those sewn slings I made. No apparent damage to the stitching <shrug>

BTW, an engineer friend saw the broken carabiner on my car floor one day. He asked if he could have one half. A few weeks later he hands me back a report, along with photo-micrographs, done by a test lab at the well known aircraft engine manufacturing plant where he worked at then time. Basically, the 'biner was made of 7075 aluminum and failed due to excessive loading after plastic deformation. There was no evidence of microfractures or any manufacturing defect. It broke from being loaded beyond what it was designed for.

Doesn't really matter. As I said, I stopped sewing slings a long time ago when sewn climbing slings became readily available. Was no longer worth my time or energy.

Disclaimer: And, at this point, I do not recommend that others sew their own climbing slings.


splish


Aug 2, 2012, 5:38 PM
Post #97 of 101 (9396 views)
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Re: [wivanoff] Sewing your own slings [In reply to]
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wivanoff wrote:
curt wrote:

That's probably a reasonable estimate. In any event, based on the ad hoc testing by wivanoff and splish himself on their own home-sewn slings and the data presented here:

http://www.caves.org/...ical/nhback/NH03.pdf

I probably wouldn't be too worried about using similar slings in a top rope anchor--particularly because I wouldn't construct the anchor to rely on a single sling anyway.

Curt

I've taken lead falls on those sewn slings I made. No apparent damage to the stitching <shrug>

BTW, an engineer friend saw the broken carabiner on my car floor one day. He asked if he could have one half. A few weeks later he hands me back a report, along with photo-micrographs, done by a test lab at the well known aircraft engine manufacturing plant where he worked at then time. Basically, the 'biner was made of 7075 aluminum and failed due to excessive loading after plastic deformation. There was no evidence of microfractures or any manufacturing defect. It broke from being loaded beyond what it was designed for.

Doesn't really matter. As I said, I stopped sewing slings a long time ago when sewn climbing slings became readily available. Was no longer worth my time or energy.

Disclaimer: And, at this point, I do not recommend that others sew their own climbing slings.

I was watching "How It's Made" on Discovery Channel the other day, and they had carabiners on there. I always thought they were made strictly of aluminum, but apparently currently, most manufacturers use an Aluminum / Zinc mixture. The zinc stiffens the biner.


wivanoff


Aug 3, 2012, 4:23 AM
Post #98 of 101 (9355 views)
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Re: [splish] Sewing your own slings [In reply to]
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splish wrote:
I was watching "How It's Made" on Discovery Channel the other day, and they had carabiners on there. I always thought they were made strictly of aluminum, but apparently currently, most manufacturers use an Aluminum / Zinc mixture. The zinc stiffens the biner.

That's what I said Wink
"Basically, the 'biner was made of 7075 aluminum and failed ..."

Zinc is the primary alloying element in 7075. It's stronger and harder than the relatively soft 6061 - which has very little zinc. It's why softer cams made of 6061 seem to grip better.

This thread really has drifted. I think I'll let it rest now.


russwalling


Aug 14, 2012, 11:06 AM
Post #99 of 101 (9111 views)
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Re: [gthomann] Sewing your own slings [In reply to]
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gthomann wrote:
Thats really impressive, especially with nylon thread, which is not all that strong. you must have done a really good stitching job. the woman at the sewing shop probably gave you a rounded point needle. I have just been using a universal needle, a rounded point would probably be better. I have sewed a few more slings (and loops at the ends of webbing) and use them when top roping, which puts little stress on them. I always show the other climbers what I am doing and give them the chance to opt out. But they are always comfortable with the slings, they know I am a crazy engineer.

Yer gonna die!!!!!!!!


MassiveD


Oct 30, 2012, 4:39 PM
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Re: [russwalling] Sewing your own slings [In reply to]
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Yer not going to buy, anyway.

Back in the 70s we sewed a lot of stuff. I know a fair bit of what I sewed on my mother's Elna grasshopper was sewn with standard thread for sewing clothing projects. 40 years latter, still waiting for the die part.

Back then in Ontario, we were lucky to have an actual engineer who worked with the UIAA safety committee to learn from. I don't know that he knew much about sewing gear from that lens, but he sewed his own seat harnesses, and we all sewed a lot of gear. I'm still using some of that gear, the slings are prehistoric.

It is fascinating to learn that all you guys are climbing with load cells and certified riggers on every trad pitch, so you know for a fact all the numbers relating to your system. All we knew how to do was limit our exposure. Make educated guesses about our placements. It's cool to know you guys deal in a world of mechanical certainty. The progress is amazing.

I probably wouldn't sew a toprope runner, since knotting it is bomber, and i can't see any upside to sewing it. But I also don't feel to bad about my 1" slings, since best case the lighter ones in use today at 100% would be weaker than my slings with a big haircut.

When we made up harnesses, we built in redundancy so there was no way we were dying. But ultimately that meant a slightly less convenient harness, so that leads to commercial gear. And anyway, today, it is hard to come up with stuff that you can't buy a better commercial version of. It was easy to build stuff when the commercial version consisted of very basic swami, leg loop combinations made of only a few webbing sizes.

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