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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Original Post - Jun 22, 2011 - 08:29pm PT
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Goofing off in the garage again.
I know next to nothing about swaging cables so I thought I might test a few. I went to Home Depot and bought an inexpensive 18" swaging tool, some aluminum swages and some galvanized cable. In comparison to Home Depo, the swaging tool at OSH was much more expensive (but probably better) and the one at Lowe's looked cheapo. I think the one at OSH had a cable cutter built in but the cable cutter in my bicycle toolbox worked fine.
1st test, 3/32" cable, single aluminum swage with two crimps, ends loaded with 1/4" diameter pin, cable broke at pin 1310 lbs.
2nd test, same as #1 except loaded with 3/8" pins, Cable broke at pin 1590 lbs.
3rd test, 1/8" cable, single aluminum swage with two crimps, ends loaded with 3/8" diameter pin, cable pulled out of swage 2430 lbs.
4th test, same as #3 but 3 crimps in swage, cable broke at pin, 2930 lbs
Home crimped swages appear to be better than I expected.
The diameter of the edge over which the loop is loaded is probably a critical factor but I would need to do more tests to verify this.
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MTucker
Ice climber
Arizona
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Jun 22, 2011 - 09:00pm PT
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http://www.mcmaster.com/#wire-rope/=cv5210
3/32
Construction Breaking Strength
Steel
1x19 Strand 1,200 lbs.
7x7 Strand Core 920 lbs.
7x19 Strand Core 1,000 lbs.
1/8
Steel
1x19 Strand 2,100 lbs.
7x7 Strand Core 1,700 lbs.
7x19 Strand Core 2,000 lbs.
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mucci
Trad climber
The pitch of Bagalaar above you
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Jun 22, 2011 - 09:03pm PT
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Hey did Bob ever give you my homemade death nut?
That was done with a Nicopress kit, might be nice to see how they match up?
Those are very inspiring numbers, with hardware gear to boot.
Thanks for the test!
Mucci
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Jun 22, 2011 - 09:48pm PT
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MTucker - nope, I didn't follow any guidelines and bought whatever crap cable they have at Home Depo. Both sizes appear to be a 7x7 if I can count that far. Like rope, webbing and cord, the breaking strength probably isn't a reliable number since these things always break at a knot, bend, etc. I'll check out the links and probably learn something. If I am going to trust my life to something, I will probably proof load each and every piece.
Mucchi - yeah, I proof loaded your nut (ha ha) to 1500 lbs as Bob requested. It survived without visible injury. I gave it back to Bob but every time we go climbing I see it as he carries it around in hopes of bumping into you.
I didn't really know how to hold it but ended up stuffing the head into a conical chuck. It's a concrete postensioning wire chuck with the wedges removed. I tested it on a 1/2 inch pin.
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mucci
Trad climber
The pitch of Bagalaar above you
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Jun 22, 2011 - 11:59pm PT
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Bitchin!
John's nut looked a lot better, more time with the wheel...useable even!
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bhilden
Trad climber
Mountain View, CA
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Jun 23, 2011 - 12:35am PT
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This might be an urban myth, but I was always told that you could make the swaged area stronger by making sure that the two cables you were connecting had their twist pattern interlocked. What that means is that the hollow between the strands of one cable is filled by one of the strands of the other cable and vice-versa.
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Tom
Big Wall climber
San Luis Obispo CA
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Jun 23, 2011 - 01:22am PT
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Nice work. Validating your process is the key to safety.
I will probably proof load each and every piece
Make sure you validate the proof loading process, by breaking some that have been proof loaded. You might proof load the thing, and wind up weakening it to the point that it's weaker than without the proof load.
What about using stainless wire rope, and the copper sleeves? McMaster.com has both. Post up the difference in strengths, as brand-new assemblies. Also, make sure you buy the unlubricated cable. They sell stainless in two grades, one of which is pre-lubricated, for running over pulleys. You don't want grease between the cable and the swaged fitting.
One of the biggest source of deadheads is galvanized cable. Galvanizing is zinc plated onto steel, to act as a sacrificial anode. The zinc corrodes away, protecting the steel in the process. But, once the zinc is gone, all you have is plain steel, which rusts out quickly.
I tried using galvanized cable, way back in the day, for tensegrity furniture, and found out that the strength was much lower than stainless cable for the same size. Or, maybe it was more susceptible to being cut over the sharp edges of the holes in the steel tubing struts. At any rate, I tried galvanized once, just once, and never tried using it again. I tried tensioning the cable for a tensegrity table base, and it didn't get even close to what I wanted, and it went POP!
I have a fetish for 1x19 wire rope. Big wires, harder to cut. Not very flexible, but for what I do I like that, and I like it alot.
That 7x19 stuff is beautiful, and very pliable, but those tiny wires are relatively easy to cut. A classic example is a funkness device, made with 7x19, with all manner of flyaways that snag fingers, webbing, etc.
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mucci
Trad climber
The pitch of Bagalaar above you
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Jun 23, 2011 - 01:33am PT
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Copper, or zinc plated copper sleeves for Galvanized steel cable.
Tin plated, or stainless steel sleeves for SS cable.
For longevity, both in the placement or the tool, follow the above.
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Jun 24, 2011 - 12:42pm PT
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I was always told that you could make the swaged area stronger by making sure that the two cables you were connecting had their twist pattern interlocked.
It can't be done. Lay two pieces of cable next to each other and on the side facing you the twists are parallel. Stack one on top of the other and you find that the twists are opposite on the contact sides, the bottom side of one strand and the top side of the other strand. You can lock the threads of two bolts this way even though the twists are opposite because the threads are nearly perpendicular to the axis of the bolt. With cables, the twists are more gradual and they end up being nearly perpendicular to each other on the contact side and cannot mesh. Coil springs never exactly mesh for this reason too.
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