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Old 27-11-2008, 10:44   #46
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I have used rings before. I think they are fine on any pins, I would not use them on turnbuckle bodies to keep the turn buckle screw from moving. I have had them move and actually bend the ring beyond any circular shape. The advantage on pins is if you loose your rig, it wouldnt take long to remove enough pins to get rid of it. Use cotter pins aloft just for extra safety.
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Old 27-11-2008, 19:13   #47
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This place cracks me up sometimes. I was going to apologize for the aviation reference but I won't.

In the absence of standards it is perfectly legitimate to examine standards in an established and well regulated industry. To my knoweldge we have never lost an airplane due to turnbuckles backing off.

And I don't care what anyone says. Cotter pins are a consumable not a reusable. That's fact.

I have seen many loose boat rigs with no safety at all. I have asked owners where the cotter pin or ring was and they had no idea that there was supposed to be one.

To put blinders on to standards from another industry is simply myopic and the not invented here syndrome can be deadly.

So use your 10 degree cotter pin idea. Up to you. Reuse your cotter pins. Up to you. Money saved on cotter pins can buy that chart plotter.

Anyhoo. This is beat to death.

I'll close with a picture of the reusable turnbuckle clips which although they are from aviation is a completely elegant solution for people who want to adjust their rig everyday. In fact I am thinking about putting these on the J24 as we adjust the rig before every race.
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Old 28-11-2008, 07:45   #48
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In the absence of standards it is perfectly legitimate to examine standards in an established and well regulated industry. To my knoweldge we have never lost an airplane due to turnbuckles backing off.
It's this part that we may disagree over. We've quoted the experts, who suggest 20. Here's another, Brion Toss:

Quote:
Proper Cotters

Unless there is some overwhelming reason to do so, never open cotter pin legs more than about 10 degrees each, so they form a narrow "V". They're no less secure than ones that are open wider, and they're much, much easier to install and remove.
Italics his not mine, The Complete Rigger's Apprentice, page 242, ISBN 0-07-064840-9.

I've made somewhat a career out of discovering things everyone knows are true, aren't. It's called evidence-based health care - find the evidence to prove what you're doing really is the best practice.

You may be right, there may be some mechanism I'm not aware of which causes reused cotter pins not under load to fail in sheer due to reuse as described above. I'm certainly, after this discussion, reconsidering my practices.

Doesn't seem to me you feel the same.
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Old 28-11-2008, 14:28   #49
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It's this part that we may disagree over. We've quoted the experts, who suggest 20. Here's another, Brion Toss:



Italics his not mine, The Complete Rigger's Apprentice, page 242, ISBN 0-07-064840-9.

I've made somewhat a career out of discovering things everyone knows are true, aren't. It's called evidence-based health care - find the evidence to prove what you're doing really is the best practice.
I think that if you rely on book reading rather than professional expertise for your own "expertise" on the use of cotter pins, then you should rely on books and standards written by and for mechanical engineers as it is in that field that mechanical fastener expertise lies. It seems to me that you are not doing that.

You say that you work in evidence based health care in which case if you wish to construct a proper investigation and analysis into the use and failure of cotter pins I am sure we would all be delighted. But it does not seem to me that you have conducted such a proper investigation - if I am wrong in that I would be delighted to see the report that has arisen out of it.

I know some here have professional experience in the use of fasteners in safety critical industries or wide industry experience in their use. Without even knowing some of them it is evident from the quality of their advice that it is very likely to be trustworthy, sincere and closely related to expertise they personally hold.

I suggest that if you wish to discard such advice that is fine, but if you wish to contest the issue with them either demonstrate some evidence that you are of equal background and experience in so far as the use of mechanical fasteners are concerned by being able to talk the talk yourself or else stop harping on trying to beat their heads into the dust.
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Old 28-11-2008, 15:47   #50
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No Question...Cotter Pins
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Old 28-11-2008, 19:14   #51
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::Shrug:: I've taken classes from Brion Toss. He's the most widely acknowledged expert I know of in lumber, crane, and boat rigging. None of those are other than safety-critical industries, but he's not a researcher. His classes are excellent, hands-on work in Port Townsend. In our class I won the hat for being the most thorough and paranoid. woohoo.

On the other hand, I haven't heard any research evidence being put forth from the other point of view, either. Just baseless accusations of ignorance, stupidity, and recklessness.

So tell me, what are your qualifications? Taken any formal classes in boat rigging? I mean, if you're going in for ad hominem attacks then certainly I have basis for asking.
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Old 28-11-2008, 20:06   #52
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Watch out guys.
Gord closed threads today for less "bickering".
He seems to be easily agitated today.

On topic though.

I don't know what to use now.
If it is put on and then all taped over then the expensive part would be having to re-tape (good tape ain't cheap ya know) every weeek(?). Sounds like a pain.
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Old 29-11-2008, 00:28   #53
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I don't know what to use now.
If it is put on and then all taped over then the expensive part would be having to re-tape (good tape ain't cheap ya know) every weeek(?). Sounds like a pain.
Reuse the tape. Buy a second plotter.

And Amgine, please don't think I am ignoring you. I've sid my piece. No need to belabor and "qualifications" wars never end happily. Suffice to say I am a 30 year engineer trained in all kinds of standards, failure modes and effects, statistics, yada, yada, yada.

You've found advice that you believe in and that's all that matters.
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Old 29-11-2008, 01:19   #54
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Personally, I’m just a little nervous taking issue with Rod Stephens, and downright alarmed to find my position at odds with Brion Toss, on anything to do with rigging.

It’s seems obvious that bending each leg of a cotter pin only 10 deg, will stress it less than would a 90 or greater degree of bend. Notwithstanding, I would have thought that the additional security of the full bend would have been preferred to the reduction of stress in a part, only bent (to any degree) once. In light of Toss’ alleged advice, I’ll have to review my opinion.
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Old 29-11-2008, 02:42   #55
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I think the 20 degree recommendation incorporates a safety feature in the sense that the pin can be removed fairly easily, what should have been added is "in an emergency".

In aviation, you'd never get the chance to mess with cotter pins in an emergency. On a boat, you might well have to wrestle with them under adverse conditions.

So you've been dismasted in a storm and need to lose the rig. What angle would you rather deal with?

Never mind about re-using them. The keyword is "removal", and for riggers, I'm sure there's just a touch of liability concern mixed into that bend.

BWS
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Old 29-11-2008, 13:07   #56
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I can get behind the 10 degree bend for ease of removing them although I still worry about the ends hanging up on stuff, especially people.

My wife came up against a cotter pin on a friends boat and left a very nasty rip in her calf.

Getting cotter pins out, whether 10 degrees or bent all around is the same tool. Side cutters and a 10 second job each.

However my big objection is to reusing them.
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Old 29-11-2008, 13:33   #57
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I don't know what to use now.
If it is put on and then all taped over then the expensive part would be having to re-tape (good tape ain't cheap ya know) every weeek(?). Sounds like a pain.
Dunno, I think the tape at even twice the price will be worth it if it stops all those people that gather on the dock with their 20 degree wedges tut tutting over the angle of my cotter pins .
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Old 29-11-2008, 17:14   #58
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Dunno, I think the tape at even twice the price will be worth it if it stops all those people that gather on the dock with their 20 degree wedges tut tutting over the angle of my cotter pins .

We know where to find you wedgie-boy!
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Old 13-12-2008, 15:51   #59
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pirate OK, I don't understand how "Vertical" works on turnbuckles

In a far earlier post, quoting Stephens' book, he wrote to bend the cotter pins vertically. I do not understand how this will keep the turnbuckle from unwinding! I have always bent them horizontally around the frame of the turnbuckle, and then wrapped them with tape to prevent tearing sails or skin.

I understand the 20 degree rule for cotter pins on clevis pins, but not on turnbuckles. The cotter pin has to come into contact with the turnbuckle frame to stop it from turning.

I HAVE watched an un-pinned backstay turnbuckle unwind with every pound of the ship against the waves. I would not leave a turnbuckle un-pinned while tuning the rigging, unless the tuning was done only at the dock, and not underway. I would think it would be constantly be unwinding while under load if it wasn't pinned...

I'd like to see a sketch of photo of the cotter pin installed on a turnbuckle without wrapping it around the turnbuckle body.
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Old 13-12-2008, 17:24   #60
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Following this thread and figured there might be some historical, as well as practical connection here. SOOOO!!- looked for details in my 1947 copy of Yacht Construction by TJC Hurd, technical manager of Camper and Nicholsons. Appears the 20 degree thing came about when bronze was used for cotter pins. Because of its brittle nature the legs were only bent 10 degrees, and the pins were not re-used. Also the correct proportions were the pin length should be 1 1/2 the diameter of the clevis pin, and the pin ends were dabbed over with white lead paste. now we would use silicone to smear the pin over.
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