How is chain made then??

[pcatterall]

Just read the PBO article on repairing a link in a chain. Our forum experts agreeing that they would not trust a welded link for various reasons, lack of test cert, inclusion of mild steel from welding process etc.
How is chain made in the first place. I guess there isn't an assembly line bending loops of bar and welding them together. I am trying to picture the process but cant get my mind around it.
I suppose there is some sort of batch testing requirement at the end of it all?

 

[sailorman]

http://www.youtube.com/watch?v=c1STTDTVlJI

http://www.youtube.com/watch?v=zRPos5uyy0A&feature=related

 

[Bosun Higgs]

Large coil of wire is fed into a machine which cuts the link length, bends it round and through the previous links, then electrically butt welds the ends. Slight health warning here - when I was involved with the chain makers it was the likes of Wheway Watson and Parsons Chain in the midlands. What happens now everything has moved to the third world might be a bit different.

There was a certain amount of bull in the PBO article you are thinking of. The machine need not be operated by a coded welder and most likely is not operated by one. Quality control might well involve some X ray testing of a percentage of links but it wont be a lot because the welding process is reliable. The dodgy bit in chain manufacture is when they come to the end of a coil of wire and have to hand weld one end to another. Such welds should always be cut out and discarded.

That said, I would be wary of a link welded by Joe in the boatyard because you dont know what you are getting. Could be excellent or a disaster waiting to happen. The Crosby link is much less risky though in my experience it didnt fit at all well into 8mm calibrated chain.

Best answer by far is not to be a cheapskate with anchor chain. You want a longer length - buy a longer length. Save money on non essentials like AIS or the chart plotter.

 

[halcyon]

Slight health warning here - when I was involved with the chain makers it was the likes of Wheway Watson and Parsons Chain in the midlands.

I remember them

Also remember the lorries going down the road with lengths of massive section anchor chain. Went to a chain maker when a Rubery Owen apprentice to pick up some parts. Arrived in this street of terrenced houses, went through a front door and walked into a massive factory making chain. I seem to remember they were hand forging links there, at least for some chain. But that was 45+ years ago, and we had a engineering industry.

Brian

 

[andygc]

In the 1970s I was, for a while, OiC of a couple of leisure craft owned by RAF Sek Kong. My predecessor arranged new moorings because of the move from Kai Tak. The chain was attached to the buoy by a ring, welded in the same way as a joining link would be in chain. The moorings were made by a commercial shipyard - that made ships, not junks. The ring was made of round bar which was a little more than 1 inch in diameter. During a typhoon the ring opened and the boat went up the beach with chain and shackle still attached. The ring opened because the weld failed. When I got there the ring was, amazingly, still sitting on top of the buoy.

Because of the argument with the insurers we had the ring examined by the metallurgy dept of the university. They found that it was a particularly hard form of steel used in shipbuilding that could not be reliably welded using conventional welding because of its particular crystalline structure - the butt joint was apparently filled by a weld, but there was no bond between the cut faces. If the ring had been tested, the boat wouldn't have been wrecked. There was no problem getting the boatyard to pay compensation for their negligent selection of materials (a length of scrap rod found on the slipway as we later discovered), but that doesn't cover the months of not having a boat when the sun's shining.

 

[Twister_Ken]

http://www.youtube.com/watch?v=c1STTDTVlJI

Fascinating!

 

[srp]

My great grandmother was a chainmaker in the Lymington area in her day. It was quite common apparently, done in a small brick-built shed in the back garden, with a little forge and a hole in the wall to feed the completed chain through. Those were the days.

 

[Bilgediver]

J


How is chain made in the first place. I guess there isn't an assembly line bending loops of bar and welding them together. I am trying to picture the process but cant get my mind around it.


I suppose there is some sort of batch testing requirement at the end of it all?

That is exactly how it is done though by automatic or semi automatic machinery.

The weld is carried out by electric welding during which the link is compressed to the correct length so producing that bead around the weld.

The chain may be just normalised or heat treated depending on the grade.

It is interesting watching the manufacture of links for ships and oil rigs which in our case were made from 76 mm bar about30 inches + long. Each bar is heated to red heat then bent through the previous ling and squeezed to shape before the electrodes create the circuit across the join for the weld IN SPITE OF THE LINK SHORT CIRCUIT.

The chain is calibrated and proof tested and the end links usually marked or labelled with cert details.

Reputable chain suppliers who deal with the leisure market obtain their chain from known suppliers in the far east and then analyse and proof test the chain on arrival in the UK and issue their own certs. Copies of these can be obtained on request in many cases.

One major supplier to chandlers seems to be Plastimo .

 

[Heckler]

Large coil of wire is fed into a machine which cuts the link length, bends it round and through the previous links, then electrically butt welds the ends. Slight health warning here - when I was involved with the chain makers it was the likes of Wheway Watson and Parsons Chain in the midlands. What happens now everything has moved to the third world might be a bit different.

There was a certain amount of bull in the PBO article you are thinking of. The machine need not be operated by a coded welder and most likely is not operated by one. Quality control might well involve some X ray testing of a percentage of links but it wont be a lot because the welding process is reliable. The dodgy bit in chain manufacture is when they come to the end of a coil of wire and have to hand weld one end to another. Such welds should always be cut out and discarded.

That said, I would be wary of a link welded by Joe in the boatyard because you dont know what you are getting. Could be excellent or a disaster waiting to happen. The Crosby link is much less risky though in my experience it didnt fit at all well into 8mm calibrated chain.

Best answer by far is not to be a cheapskate with anchor chain. You want a longer length - buy a longer length. Save money on non essentials like AIS or the chart plotter.

It wasnt bull, I wrote it! My life depended on those pipe joints offshore, we were pumping gas back down the hole at 5000psi, it had H2S in it which enbrittles steel. We always did 100 percent NDT Xray. Onshore we did 30% Xray, it wasnt so critical. The sub left that bit out. The guy who wrote in had a weld done on a life critical piece of kit, I asked the question was it tested? As you yourself point out you would be wary of Joe in the boatyard doing the welding.
Stu

 

[nigelmercier]

http://www.youtube.com/watch?v=c1STTDTVlJI

So, so wrong without Tony Hirst doing the voice-over.

...you would be wary of Joe in the boatyard doing the welding.

And ever more wary of Carlos or Nikos


As an aside, where can I find the dimensions of calibrated chain? I'm building an electronic chain counter so I need to know how much chain is dropped by one revolution of the gypsy. I've measured it, but it would be nice to have solid facts.

 

[Heckler]

So, so wrong without Tony Hirst doing the voice-over.



And ever more wary of Carlos or Nikos


As an aside, where can I find the dimensions of calibrated chain? I'm building an electronic chain counter so I need to know how much chain is dropped by one revolution of the gypsy. I've measured it, but it would be nice to have solid facts.

Even Stu!, I can weld pretty good, but I wouldnt weld a link in my anchor chain. Well maybe I would, but I would be looking at doing some heat treatment afterwards! And some research as to what the links were made out of!
Stu

 

[Poignard]

My great grandmother was a chainmaker in the Lymington area in her day. It was quite common apparently, done in a small brick-built shed in the back garden, with a little forge and a hole in the wall to feed the completed chain through. Those were the days.

No doubt with a baby strapped to her back as well!

 

[electrosys]

My great grandmother was a chainmaker in the Lymington area in her day. It was quite common apparently, done in a small brick-built shed in the back garden, with a little forge and a hole in the wall to feed the completed chain through. Those were the days.

Apparently that's the way ship's chains were made in the Black Country in the days of Brunel - each house producing it's quota which was then added to that of it's neighbour.

 

[fergie_mac66]

Fred dibnah

In one of his episodes he goes to an old fashioned chainmakers In the midlands

 

[vyv_cox]

There was a certain amount of bull in the PBO article you are thinking of. The machine need not be operated by a coded welder and most likely is not operated by one. Quality control might well involve some X ray testing of a percentage of links but it wont be a lot because the welding process is reliable. The dodgy bit in chain manufacture is when they come to the end of a coil of wire and have to hand weld one end to another. Such welds should always be cut out and discarded.

That said, I would be wary of a link welded by Joe in the boatyard because you dont know what you are getting. Could be excellent or a disaster waiting to happen. The Crosby link is much less risky though in my experience it didnt fit at all well into 8mm calibrated .

I suggest you read it again, a little more carefully. There was no question of a coded welder operating a chain making machine, the question answered by Stu and myself referred to a making a joining link by butt welding in an existing chain.

The QA reference also had nothing to do with chain manufacture. It contrasted the typical requirements for other safety related equipment such a oil field tubulars with the 'Joe of the boatyard' method that had been proposed.

 

[LadyInBed]

where can I find the dimensions of calibrated chain?

Is this link for Grade 30 Calibrated Short Link Chain of any help?

 

[Bosun Higgs]

I suggest you read it again, a little more carefully. There was no question of a coded welder operating a chain making machine, the question answered by Stu and myself referred to a making a joining link by butt welding in an existing chain.

The QA reference also had nothing to do with chain manufacture. It contrasted the typical requirements for other safety related equipment such a oil field tubulars with the 'Joe of the boatyard' method that had been proposed.

I'm not going to have an argument on the forum so I have sent you a pm.

 

[nigelmercier]

Is this link for Grade 30 Calibrated Short Link Chain of any help?

Almost, but it's the distance (say) from one weld to the next that I need to know.

 

[Bilgediver]

Almost, but it's the distance (say) from one weld to the next that I need to know.

It tells you that too ..

 

[LadyInBed]

the distance (say) from one weld to the next that I need to know.

Weld centre to Weld centre = B/2+B+B/2 or 2B . . . C . . . I mean See