Labs that test CCH Aliens?
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Does anyone test old CCH Aliens these days? I'd like to get some tested to 1/2 or 1/3 of their stated strength. |
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Bounce test the fuck out of them! Static line and a crash pad... |
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get some accessory cord rated to fail at the strength you wanna test. pull till cord breaks. done. |
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Jordan Ramey wrote:get some accessory cord rated to fail at the strength you wanna test. pull till cord breaks. done.If you do it this way be sure to de-rate the cord strength to account for the knot(s). Another option was put forward by Mike Rawdom (Gunkiemike on RC, IIRC) where he used his sewing machine and 1" webbing to make breakable fuses. Basically he used the thread strength to calculate the number of stitches needed to get the strength he was looking for and the handful I broke for him failed within a couple percent of what he calculated. |
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Jordan Ramey wrote:get some accessory cord rated to fail at the strength you wanna test. pull till cord breaks. done.What do you use to pull? A vehicle? What do you attach the cam to? Anybody know if Gabe O sells his "fuses?" |
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Yep, that was me. Here's a link: |
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Did you ever get one of your fuses tested to confirm your assumed strength range? |
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Cord fuses are only good for a rough ballpark, as loss of strength due to the knot is highly dependent on the knot used, how it's dressed, which strand is loaded and how closely the manufacturer puts the rated strength to the actual breaking strength. At best you're likely looking at +/- 10% or so from your calculated value, but it doesn't really matter if it breaks at 5.5kN rather than 5.0kN since a ballpark figure is good enough for this sort of thing. |
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Throw those janky pieces of crap in the garbage and buy some new ones from Fixe when they come out. How much is your life worth? |
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I thought it was pretty clear that this pull testing to 1/3 or 1/2 rated strength was completely worthless for predicting performance and in fact just sets up the pieces to fail prematurely anyway. |
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sfotex wrote:Throw those janky pieces of crap in the garbage and buy some new ones from Fixe when they come out. How much is your life worth?Hahahah. Aliens have been saving my life since 1997. Just because CCH made a few bad ones doesn't mean there aren't tens of thousands of good ones out there. People are still buying and driving Toyotas, aren't they? --Marc |
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Stich wrote:I thought it was pretty clear that this pull testing to 1/3 or 1/2 rated strength was completely worthless for predicting performance and in fact just sets up the pieces to fail prematurely anyway.If you go to the link provided by Gabe, I don't think it's clear at all that pull testing is completely worthless. He came up with a rather scientific way to put a significant load on each unit and hasn't had one break yet. I don't think the method is perfect, but it's certainly good enough for me; I also think it's better than a) wasting the money that I spent on the cams by throwing them away and b) acting on blind faith/assuming they're good without actually knowing. youtube.com/watch?v=jMeGtWj… Stich wrote:That said I have two old Aliens that I have on the rack and I just take it on faith that they were good ones.It makes heaps more sense to me to pull test my cams rather than acting on blind faith, or gambling that the ones that I own don't have QC issues. But to each his own. Stich wrote:That's all I can do.Is it, though? --Marc |
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I don't know where the original post from an actual engineer that described why pull tests are useless is, but it was interesting to read. Perhaps you can consult someone who can explain it all in detail, but that was the gist of it. |
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Guess Metolius didn't get the memo, as the individually proof test their gear without damage. |
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Stich wrote:Believe what you want.For me, it's not what I want to believe, but what makes sense to believe. Several people on the thread (Gabe, Aric & Russ) with gear-testing experience seem to believe that pull testing a CCH Alien gives them a little more integrity than what they currently have at face value. It sounds like you're the one that's believing what he wants to believe. :-) --Marc Edit: it appears at least one of the aforementioned people is financialy.. Er drunkinly, invested in me believing that pull testing is worth it. ;-) Russ Walling wrote: We can pull them for you. Cost is a 750ml of Tequila. |
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I just would like to reiterate, |
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Russ Walling wrote:Email me if you want to get the ball rolling. Cost is a 750ml of Tequila.PM sent. Bottle purchased. |
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Marc H wrote: People are still buying and driving Toyotas, aren't they? --MarcThat's in large part because a panel of NASA scientists put together by the Federal Gov't researched it and found no reason in any system why those accidents happened. Sorry, couldn't let that go, big Toyota fan. Carry on with your Alien discussion. |
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Rick Blair wrote: That's in large part because a panel of NASA scientists put together by the Federal Gov't researched it and found no reason in any system why those accidents happened.Maybe they should have used engineers that build cars instead of rockets. :-O |
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Brad W wrote:Did you ever get one of your fuses tested to confirm your assumed strength range?Nope. I did talk to one of the engineers at Sterling Rope to confirm that the MBS is close enough to the breaking point for my comfort level. As Russ and Aric implied, if you're testing to 1/2 breaking strength, you've already accepted the fact that your test is only weeding out cams with a failure mechanism at the low end of their rated strength. That was good enough for me. GO |
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Russ Walling wrote:LOLLLLLLLLLL |