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jimfix
Nov 29, 2004, 2:29 AM
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I was wondering if anyone makes their own slings with an industrial sewing machine. Is there anything that makes the manufactures sewing special?
I know testing bla bla bla, but slings arn't all tested before sale are they.
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eyecannon
Nov 29, 2004, 3:15 AM
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I, for one, wouldn't climb on it, no matter how good of a seamstress you claim to be. Just tie a water or beer knot instead.
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grj
Nov 29, 2004, 3:31 AM
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No, slings are not individual tested as some manufactures (Omega Pacific) do to carabiners. Carabiners can be tested by half loading without any adverse effects to it. While, a sling, being made out of nylon/spectra threads, isn't quite the same. However, the manufactures do test many samples from each product they sell before releasing it to the public (thus how each product's strength rating is determined).
As for making your own slings, props to you for innovation! I would just highly recommend actually testing several first before using them. Are you a student at some University where you have access to a Materials Testing Lab in the Engineering building? Most of the big climbing equipment manufactures out there began with someone thinking, "I can make something better than what is already out there for less money." Being the engineering type I am, someday I think I'll attempt to make my own cams, however I plan on testing them extensively first before ever climbing on them. Also, nobody will probably be willing to climb on your homemade equipment unless they were involved in the testing process of it.
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rossgoddard
Nov 29, 2004, 3:40 AM
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In reply to: One note about slings and webbing: webbing tied into a sling with water-knots is great for top roping and static loads but should not be used with dynamic loads as in sport or trad climbing. |
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thegreytradster
Nov 29, 2004, 3:42 AM
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EVERYBODY! used tied slings pre late 70's with no ill effect. They can handle dynamic loads just fine. Use a water knot with 2:"-3" tails and clip them to something and stomp the knot down tight before use, (important!). Use only 1" or 9/16" webbing and don't tie Spectra.
The investment in an industrial sewing machine and the time required versus the relitively low cost, makes making your own sewn slings foolish both from an economic and quality control standpoint.
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nmoroder
Nov 29, 2004, 4:03 AM
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In reply to: Is there anything that makes the manufactures sewing special?
YES!
Do a little research or a search.
This question gets asked all the time.
In reply to: One note about slings and webbing: webbing tied into a sling with water-knots is great for top roping and static loads but should not be used with dynamic loads as in sport or trad climbing.
This is just plain wrong...
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grj
Nov 29, 2004, 4:04 AM
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Ok maybe I spoke too soon on the water-knot thing... It is just important to note that water knots do slowly creep so always double check them. I still prefer using slings for lead and webbing for top roping. I guess I error sometimes on the side of caution with use of my equipment, but it is always better than being less cautious. :-)
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asandh
Nov 29, 2004, 4:12 AM
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:D
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climbtothebeet
Nov 29, 2004, 4:18 AM
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for the price of slings, y not just buy some? u can get tehm cheeper than a biner of u look hard enough.
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boltdude
Nov 29, 2004, 4:35 AM
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Just tie your own, leave long tails, and buy black/tan/gray webbing - 'cause sooner or later you'll leave that sling on an anchor and there are more than enough ugly yellow and blue and purple slings on the rock...
Tied slings are way more versatile in any case.
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anykineclimb
Nov 29, 2004, 5:07 AM
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If you've already got an industrial sewing machine, go for it. just be sure to do a LOT of testing. Keep in mind also that you'll end up wasting lots of webbing in load testing. better to just buy them or tie waterknots.
If you don't have a machine and the sole reason for getting one is to sew slings, don't bother. No reason to spend $700+ for a machine that will only do slings. On the other hand, if you're planning on making other stuff...
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jimfix
Nov 29, 2004, 10:41 PM
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Thanks all, and sorry for wasting your time. Looking back at previous threads (no pun intended), homemade gear isn't worth the time and cost unless you are making prototypes.
I didn't run a search before I posted this, as until now I've had very little success with the search tool (maybe because I use a Mac?).
It was interesting to see that some people believe that barracking isn't the strongest method for joining. Stitching in the line of force is better, so why don't climbing gear manufactures use this stitch?
BTW, I was looking at picking up a second hand machine for ~$130 US. And my partner wants it to make horse gear, climbing gear would be an on the side project. Also, as climbing gear is more expensive in New Zealand, it may be worth my time. However, testing etc is probably more hassle than it's worth.
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slacklinejoe
Nov 30, 2004, 2:07 AM
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In reply to: It was interesting to see that some people believe that barracking isn't the strongest method for joining. Stitching in the line of force is better, so why don't climbing gear manufactures use this stitch? BTW, I was looking at picking up a second hand machine for ~$130 US. And my partner wants it to make horse gear, climbing gear would be an on the side project. Also, as climbing gear is more expensive in New Zealand, it may be worth my time. However, testing etc is probably more hassle than it's worth.
Jim,
I sew industrial stuff all the time (slacklines) there is a lot to getting it down and most people aren't nearly prepared for how much of a pain in the arse it is to sew high tensile strength things. You would NEVER want to use normal threads ect, and most "industrial" machines you see that are affordable won't run the necessary threads reliably without major tweaking and sacrifices to deities. There is a big difference between industrial machines - some people will sell a old looking home machines or new plastic home versions as an "industrial" out there - totally unethical, but EBay is chocked full of them all listed as such.
Anyrate, without loads of experience and testing I can't recommend anyone undertaking sewing their own slings or life critical sewing.
As to why bartacking and not other methods beats me to death on that one. Other methods are slightly stronger (a few percent) but problem is it's more complex by a good margin and can actually be slower to make and more time consuming to not use bar tacks.
I used to take the time to do non-bar tack my slacklines I was selling (doing those nice strong patterns ect) but people kept thinking "well if my harness uses bar tacks it must be the strongest out there" which isn't quite true. Bar tacks are easier to make, strong, but not the most stitch efficent or over all as strong since the close proximity of the piercings weaken the webbing more than the usual 10-15%. However, I got too many requests to switch despite no one ever breaking a stitch just because they thougth bar tacks were stronger since their climbing gear had them. (gotta give people what they want)
Please PM me if you want additional tips on picking out a machine that will fit your friend's needs.
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fear
Nov 30, 2004, 3:01 AM
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[quote="slacklinejoe"]In reply to: As to why bartacking and not other methods beats me to death on that one. Other methods are slightly stronger (a few percent) but problem is it's more complex by a good margin and can actually be slower to make and more time consuming to not use bar tacks. I used to take the time to do non-bar tack my slacklines I was selling (doing those nice strong patterns ect) but people kept thinking "well if my harness uses bar tacks it must be the strongest out there" which isn't quite true. Bar tacks are easier to make, strong, but not the most stitch efficent or over all as strong since the close proximity of the piercings weaken the webbing more than the usual 10-15%.
Oh my god. I think I learned something interesting on rockclimbing.com. Holy Sh!t....
-Fear
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slacklinejoe
Nov 30, 2004, 3:10 AM
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Fear, I have three sources for that information if you were wondering. However, I have not tested this first hand.
One is an old manufacturing book on product design, I don't remember the exact percent it mentioned but it was like 1-2% difference. Another was a industrial sewing company (my mom worked in the leather and high strength sewing industry for 28 years), and one of my suppliers who sells industrial thread and webbing. The book listed the bar tack and other methods as interchangable. It recommended the bar tack for any time when it was desirable to get lots of strength in the smallest possible area, and just accept that it will weaken your material some. If you go too close together of a zig zag you get additional problems like bulging that rapidly affects quality and strength as well.
The military has what is called a "box tack" specification as well as a diamond tack specification ect that they use on different products. If you look at most industrial webbing equipment (tow straps, lifting equipment) they aren't bar tacked, but instead a straight stitch with a design in it that keeps a distance away from other stitches (diamond patterns, X's ect).
As far as testing the gear myself, I never noticed a difference (not that 1% would be visible to my relatively inaccurate tests). Neither broke under normal use, and both would break the webbing first, usually at the stitching where it weakens it.
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