Crosby C links - peening studs
- Thread starter JimC
- Start date
scruff
Well-Known Member
I found I needed a pretty heavy hammer and a punch to get it set. I used on 8mm chain and it was a pig of a job.
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I used a static ball pein and whacked it with a 4lb lump hammer whilst the link rested on the side of another lump hammer. I'm sure it's a common engineering technique but I was inspired by George Clooney making a rifle silencer in The American.
vyv_cox
Well-Known Member
When I did a lot of them for destructive testing I placed the chain loosely in a big vice with the C-links horizontally on the jaws. This holds it all in place for peening. I used a 2lb lump hammer with a short length of round bar as a drift, about 3/4 inch diameter.
JimC
Well-Known Member
I've just done a trial run with the Crosby horizontally on the vice as Vyv describes and the two halves of the link engaged together but no chains in place; just aiming to see how the peen started without enlarging it enough to prevent the two halves being pulled apart. I was hitting the stud hard with a flat-faced hammer of about 2 pounds. When I separated the halves I found I had slightly bent the stud but not expanded its diameter at all.
Gary Fox
N/A
Doing it on board using the engineering facilities of an average cruising yacht, to a repeatable standard which you trust to hold you to anchor in heavy weather, seems almost insurmountable.
I have been carrying around a couple of 10mm Crosby chain joiners for years, without even trying because I don't have a big enough anvil or vice to hammer them on. (The actual hammer isn't so much of a problem).
Another point: If you went to the trouble of loading the chains to be joined in a vehicle, and had a friendly workshop to ket you use heavier facilities, what would be the ideal way to do it? Lots of light hammer blows? One very heavy blow?
How can you judge if it is done properly, the whole proceedure seems fraught with pitfalls, and unlikely to promote a good nights kip at anchor.
How about slowly squashing the pins in a huge press, until they spread into their holes? (This last sounds favourite to me, but I have no way of telling if it is correct or even safe.)
I have been carrying around a couple of 10mm Crosby chain joiners for years, without even trying because I don't have a big enough anvil or vice to hammer them on. (The actual hammer isn't so much of a problem).
Another point: If you went to the trouble of loading the chains to be joined in a vehicle, and had a friendly workshop to ket you use heavier facilities, what would be the ideal way to do it? Lots of light hammer blows? One very heavy blow?
How can you judge if it is done properly, the whole proceedure seems fraught with pitfalls, and unlikely to promote a good nights kip at anchor.
How about slowly squashing the pins in a huge press, until they spread into their holes? (This last sounds favourite to me, but I have no way of telling if it is correct or even safe.)
scruff
Well-Known Member
I did it one spring when in the boat yard - chain dropped to the ground and used a masonry lump hammer as a make shift anvil.
repeated heavy blows got the "pins" hammered flat with no play. As per my previous post, getting the chain into the link and the two halfs lined up ready to battered into shape was a right pig of a job.
Now it's done - I'm confident it is well strong enough to give me a good nights sleep - indeed I sat out a summer storm quite happily since.
Would I do again or just buy a whole new length of anchor chain...
Poignard
Well-Known Member
For an anvil I used a flat iron clamped upside down in a Black & Decker Workmate.
Kwik Decision
Well-Known Member
I've also done a couple of 10 mm Crosby links, in the yard the way scruff describes, and it was a straightforward job. The peening over of the pins is simply to stop the link coming apart, and (provided they are peened sufficiently to hold both halves securely together) does not contribute to the strength of the link. I've anchored quite happily on board that boat since doing so.
Gary Fox
N/A
Thanks, I did not realise that the peening over the pins did not contribute to the strength as you say.
JimC
Well-Known Member
It may not contribute to the strength but if there is play there will be movement and if there is movement there will be wear. I don't have a windlass so I think it's going to be a pair of back to back shackles.
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Neeves
Well-Known Member
The idea of doing it on the deck is surely a joke.
Take all the chain off and make the join on concrete, ideally with a steel plate on the concrete and a 4lb hammer as an anvil. Use a HT bolt as a punch and another 4lb hammer. Try to use G100 HT bolts, its usually listed on the side of the bubble pack that the bolts are in when you buy them and there are codes on the bolt head which also define the strength, google for the codes. The rivets will contribute to strength, but most of the strength will be from the 2 HT 'C's.
Do not be tempted to weld the links - they will revert to the strength of a mild steel and you have wasted your time and money.
When you have joined the 2 sides of the link consider giving a coat of a liquid gal and as you use the chain give the 'C' link a quick look to check for integrity - but if you have joined together properly with no movement - it will remain secure. You might want to re-coat the 'C' link with a liquid gal on an annual basis.
Its obviously easier to do all of this in a well equipped workshop but if you are joining 2 x 50m of 10mm c chain - its actually quite heavy
and working on a concrete wharf is easier. As you have the chain on the wharf - update your length marks.
Jonathan
Take all the chain off and make the join on concrete, ideally with a steel plate on the concrete and a 4lb hammer as an anvil. Use a HT bolt as a punch and another 4lb hammer. Try to use G100 HT bolts, its usually listed on the side of the bubble pack that the bolts are in when you buy them and there are codes on the bolt head which also define the strength, google for the codes. The rivets will contribute to strength, but most of the strength will be from the 2 HT 'C's.
Do not be tempted to weld the links - they will revert to the strength of a mild steel and you have wasted your time and money.
When you have joined the 2 sides of the link consider giving a coat of a liquid gal and as you use the chain give the 'C' link a quick look to check for integrity - but if you have joined together properly with no movement - it will remain secure. You might want to re-coat the 'C' link with a liquid gal on an annual basis.
Its obviously easier to do all of this in a well equipped workshop but if you are joining 2 x 50m of 10mm c chain - its actually quite heavy
and working on a concrete wharf is easier. As you have the chain on the wharf - update your length marks.Jonathan
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