Cotter Pins again

[Capt_Marlinspike]

I was browsing the Brion Toss rigging web site the other day and I noticed that he said:
"Stainless steel cotter pins are an abomination and that he only ever uses bronze"
he says this is because they are:
"too stiff, too brittle, to horribly hard to remove"

Does anyone one here use bronze?


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[Plum]

I assuse that if I translate cotter pin to English you are refering to a "split-pin", the pin you put in the hole of a clevis pin and then bend the two legs apart. No, I have never used, or ever seen for sale, a bronze split-pin.

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[AndrewB]

Monel?

Never. Been tricked by a good few mild-steel pins though. They may not be stiff or brittle, but they are a pain in the arse to remove when they rust in!

I don't think the brittleness of stainless really matters, except that they shouldn't be reused, at least not more than once.

Removing them admittedly can be tricky in tight corners, requiring knack - or a hacksaw. I sometimes use monel wire, twisted together at the ends, as a substitute for a cotter (split) pin in a hard to access spot. Less problem with removal, but I've wondered if this is good practice.

 

[Aja]

Cotter pins are not the same as split pins.

Cotter pins may be used to hold two parts of rigging together, for example a bottlescrew to a chainplate. Cotter pins may be held in place by split pins.

They may be made out of either stainless or bronze, though stainless is the much more popular.

Regards

Donald



<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by Donald_Beaton on 26/03/2004 13:48 (server time).</FONT></P>

 

[AndrewB]

I think you may be confusing cotter and clevis pins. Could you check the illustration <A target="_blank" HREF=http://www.gen-aircraft-hardware.com/template.asp?pagename=cotter>HERE</A>? Incidentally, I see this firm actually sell brass cotter pins - probably what Brion Toss means by bronze.

PS The term 'cotter pin', for split pin is mainly used in the US.

 

[Aja]

Oooh your'e right. I stand corrected.
So. What's the difference between a cotter and a split pin then?

Donald

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[AndrewB]

There is an English word 'cotter' for the wooden wedge used to secure fastenings. I have a refectory bench - popular at the time of the stripped-pine furniture boom - whose legs are supported by a cross-beam secured with 'cotters'. I guess this is where the term originates.

 

[Sniper]

When I was young and rode a pedal cycle, a cotter pin was what held the pedal arm to the crank. It was a tapered metal pin with a threaded end. You banged it into place and then fastened a nut onto the thread to stop the pin working out.

Sounds like a similar principle to the Medieval bench.

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[Georgio]

I tend to use Split-Rings where ever possible, much kinder on fingers, sails and are reusable if not bent.

Having large split rings in bottle screws allows me to easily adjust rig tension mid season if necessary.

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[chippie]

Horatio I was about to cite the same example. You must be right!

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[ongolo]

I am not sure this time, I am not english but cotter pin is a Federstecker in German,

And it is a wire, with a straight part, then comes a 220degr. bend, then it bends away from the straight part again to form an angle to go back down again towards the straight part and away agaim. The material is springy and the cotter pin is used to stick a cross a shaft or a pin. It secures non critical pins very quickly and by just pushing into a hole to hold itself. In function similar to a split pin, but it is made to be reused for ever.

If this is NOT a cotter pin, then WHAT is a cotter pin?


regards ongolo

<hr width=100% size=1>1000 dream about it, 100 talk about it, 10 start and 1 completes it

 

[chippie]

Ongolo, what you describe is often used for connecting parts of agricultural machinery here, I dont have a technical name for it.

I have just done a google search for cotter pins and find that the term seems to be synonomous with split pins to the engineering supply companies.

Perhaps the term indicates the function rather than the configuration.

I always thought the best example was, as stated before, the round pin with a tapered flat side and a nut on the end, that holds the bicycle crank together by wedging against a flat on the shaft. Andrew B's point about wedging tallies with this.

It looks like more google searching is in order.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by chippie on 27/03/2004 23:16 (server time).</FONT></P>

 

[Avocet]

I think what Ongolo describes might be an "R" pin but I'm not sure. Does it look like an upper case letter "R"? I've seen them used on racing cars instead of split pins - they can be removed very quickly but (essentially) do the same job. If I could find some very big ones I'd like to hold my stanchion tubes into their bases with them so I can quickly pull them out if ever I need to recover a MOB but I've never found really big ones and I've a feeling the jib sheets would get caught on them in any case. Just as a complete and blatant thread hijack, how do people hold stanchion tubes in?

Anyway, I understand a cotter pin to be a cylindrical metal peg which then has a tapered flat machined on one side to make it into a wedge. At the thin end, a thread is formed so that the wedge can be pulled tight against its mating face with a nut (as on a bicycle pedal). As for why the original poster was asking why stainless was not to be used, I haven't a clue! I would have though the material choice would be dictated by what the surrounding components were made of to avoid electrolytic corrosion? Stailess is a lousy bearing surface - it "galls" up very easily (i.e. when two parts are slid together under high load they tend to bind up and tear lumps out of each other's surfaces. Stainless rigging screws are a good example - unless the threads are very well lubricated, they are easy to damage when tightening. Maybe that's why they make lousy cotter pins?

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[ongolo]

Chippie and avocet, I think you are both right, I came across cotter pins and instructions in manuals but I cannot remember where.

I think what I described one could calle an R-pin, wich has an extra nick or bend in the middel where it is secured.

I think the bolts holding gear levers and kick starters are also called cotter pins.

I checked encarta and it says :
pin or wedge that hold machine parts together (14th centrury, origin unknown)

I think another poster was also right, I can imagine that the wedges holding the cross member on old wooden tables were called cotters.

Whatever Cotters or cotter pins are, split pins they are not.

I checked at a dictionary site of the Technical University Chemnitz, and they invite corrections, so I aminterested to know.

Incidently, in olden days before the common use of (handmade) screws, wedges (cotters?) were the only means besides rope to hold things together if later dismantling was required, dowels were used for permanent connections.

The history of thread is quite interesting until Withworth invented his "screw cutting" lathe. But I am getting uinto history now and people might not be interested in that.

regards ongolo


<hr width=100% size=1>1000 dream about it, 100 talk about it, 10 start and 1 completes it

 

[chippie]

Avocet, visit a tractor sales outlet. I have seen some that would go through about an inch shaft,unfortunately not stainless.The bigger ones are very stiff to use as they are correspondingly thicker. I wonder if you could get some made up, or even make them yourself out of stainless.

I've seen stanchion tubes held in with a stainless bolt and locknut but they looked a bit clumsy,somewhere I saw some with a stainless ball and spring that popped into a hole. Mine are one piece and work by impaling the crewmember before he goes overboard;-)

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[castaway]

Me too.. so thats settled... Nick

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[andyball]

Re: Big r-clips

Should be able to find large stainless ones if you hunt around enough custom m/cycle parts suppliers....they're certainly made.

also here

 

[Avocet]

Re: Big r-clips

Thanks all! Interesting thought, though Chippie! I'd have to sharpen my stanchions but I could usefully replace the guard wires with barbed wire too!

Thanks too, Andy, will check those out!

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