Cutting G70 chain

[stranded]

I need to chop off some of my 8mm g70 anchor chain. I understand it may be a bit tough for a hacksaw? I’ve got a fein multitool, but am bamboozled by all the different attachments. Is there one that would do this? Or do I need to add a cordless angle grinder to my special “all the gear, no idea” tool chest - and in which case, again, what sort of disk?

 

[ash2020]

Cordless angle grinders are fab. It's probably my most used tool. This one is particularly good.
Ecosia - the search engine that plants trees

 

[noelex]

A hacksaw will cut it quite quickly and easily if you dont want to be bothered with an angle grinder.

Mole grips or similar are useful to hold the link while cutting. Don’t cut on the deck unless you want to be chasing tiny rust spots for an eternity.

 

[vyv_cox]

No problem at all with a hacksaw. If you don't have a vice that can be used on board it is a great investment.

 

[Roberto]

+1 for hacksaw,, no problems even with G100 12mm fittings, I suppose harder than G70 (?)

 

[vyv_cox]

+1 for hacksaw,, no problems even with G100 12mm fittings, I suppose harder than G70 (?)

Yes, there is a direct relationship between strength and hardness. I am guessing it has about the strength and hardness of 8.8 bolts, quite easy to hacksaw with a bit of effort.

 

[Neeves]

Why not simply use bolt croppers, which you will carry as part of your emergency gear. I cut some this afternoon.

I've cut, chopped G120 - with ours.

Why, on earth, are you chopping of some G70 chain?

Do not use an angle grinder on deck - the sparks are white hot HT steel - they will embed in your gelcoat and you will have the rust marks for ever. Do it on shore (similarly with bolt croppers but different reason) you need a bit of oomph to cut HT chain (with bolt croppers) but its more controlled than an angle grinder.

If you have and use bolt croppers. engage the bolt croppers and wrap with a rag, old towel, make the first cut. Use the same procedure for the second cut, on the other side, as when the second cut 'works' the chain 'sort of' explodes and the two halves of the link fly off like bullets. It stops you injuring fascinated observers.

Jonathan

 

[stranded]

Why not simply use bolt croppers, which you will carry as part of your emergency gear. I cut some this afternoon.

I've cut, chopped G120 - with ours.

Why, on earth, are you chopping of some G70 chain?

Do not use an angle grinder on deck - the sparks are white hot HT steel - they will embed in your gelcoat and you will have the rust marks for ever. Do it on shore (similarly with bolt croppers but different reason) you need a bit of oomph to cut HT chain (with bolt croppers) but its more controlled than an angle grinder.

If you have and use bolt croppers. engage the bolt croppers and wrap with a rag, old towel, make the first cut. Use the same procedure for the second cut, on the other side, as when the second cut 'works' the chain 'sort of' explodes and the two halves of the link fly off like bullets. It stops you injuring fascinated observers.

Jonathan

We need to lose some corroded links at the business end, and the 100m of chain we carry is overkill now our cruising horizons have shrunk due to family circumstances, so 60 or 70m should be fine.

We dont carry bolt cutters - sound very difficult to use in circumstances where they are most likely to be required, we have a very strong rig, don’t do voyages longer than two or three days and only then with settled weather forecasts. We don’t carry harpoons to shoot the orcas off Galicia either.

Noted re the angle grinder - we have had evil done to our hull in the past by an idiot marinero with an angle grinder on the pontoon.

Anyway, sounds like a hacksaw should do the job, with less risk than either boltcroppers or an angle grinder.

No-one’s commented on the fein question - is that because it’s not possible, or simply that no-one has tried it?

 

[Neeves]

We need to lose some corroded links at the business end, and the 100m of chain we carry is overkill now our cruising horizons have shrunk due to family circumstances, so 60 or 70m should be fine.

We dont carry bolt cutters - sound very difficult to use in circumstances where they are most likely to be required, we have a very strong rig, don’t do voyages longer than two or three days and only then with settled weather forecasts. We don’t carry harpoons to shoot the orcas off Galicia either.

Noted re the angle grinder - we have had evil done to our hull in the past by an idiot marinero with an angle grinder on the pontoon.

Anyway, sounds like a hacksaw should do the job, with less risk than either boltcroppers or an angle grinder.

No-one’s commented on the fein question - is that because it’s not possible, or simply that no-one has tried it?

If you are using a hacksaw then it will be easier if you have a decent vice, a big one 4". Bolt it to a piece of wood and have someone stand on the wood. It will not be quick.

I'd check with neighbours and friends - someone might have bolt croppers - its quick.

Fein - I don't know what one is - and thought the word referred to a type of snow. . But I'm a bit ignorant and need to get out more.

Jonathan

 

[penfold]

Multitool may do it but from experience you'll die of old age before it cuts through.

 

[stranded]

https://www.powertoolworld.co.uk/fe...Fjh1fSVHdVrO57vbeYbPcEFk6fgxuWOxoCbG4QAvD_BwE

 

[Sandy]

If you can get your hands on a reciprocating saw it should make light work of it.

 

[stranded]

Well that was a bit of an anti-climax. Thought I’d try a bi-metal hacksaw first. Cut through it like butter. So easily that I now don’t believe it is actually g70, so my wife faces another summer of me sitting at the bow whenever a zephyr raises more that the mere hint of a ripple muttering “it’ll never hold”.

 

[Neeves]

Well that was a bit of an anti-climax. Thought I’d try a bi-metal hacksaw first. Cut through it like butter. So easily that I now don’t believe it is actually g70, so my wife faces another summer of me sitting at the bow whenever a zephyr raises more that the mere hint of a ripple muttering “it’ll never hold”.

Vyv has a simple test for hardness using small ball bearings.

Find a source of steel of the hardness you think your chain might be, say a HT bolt.

This is the difficult part make a sandwich of suspect product, chain link, the ball bearing and the defined product of hardness - the bolt. Clamp in a decent vice and wind up the pressure. If the bolt and the link have the same depth of indent made by the ball bearing - then they are of the same hardness.

G70 chain will be marked 'G70' - it may only be marked every few links so you need to have a couple of metres and look at it carefully. If it is CMP Titan chain it should also be marked CMP and Titan. If its American chain it will also be marked USA. Campbell mark their chain C7, Peerless mark some of their chain P7, I think Maggi used A4 or A7 (for Aqua) - its a bit varied and a bit confusing - but there is not much room on a link to mark very much

I can confirm G70, and higher, is hard to cut, even with bolt croppers.

Jonathan

 

[stranded]

Vyv has a simple test for hardness using small ball bearings.

Find a source of steel of the hardness you think your chain might be, say a HT bolt.

This is the difficult part make a sandwich of suspect product, chain link, the ball bearing and the defined product of hardness - the bolt. Clamp in a decent vice and wind up the pressure. If the bolt and the link have the same depth of indent made by the ball bearing - then they are of the same hardness.

G70 chain will be marked 'G70' - it may only be marked every few links so you need to have a couple of metres and look at it carefully. If it is CMP Titan chain it should also be marked CMP and Titan. If its American chain it will also be marked USA. Campbell mark their chain C7, Peerless mark some of their chain P7, I think Maggi used A4 or A7 (for Aqua) - its a bit varied and a bit confusing - but there is not much room on a link to mark very much

I can confirm G70, and higher, is hard to cut, even with bolt croppers.

Jonathan

Thanks Jonathan - that’s what I thought - why I was expecting a battle with it. But it was so easy - once I managed to clamp it firmly enough it took maybe 30 - 45 seconds per half link - I didn’t actually time it. Thing is it is Maggi Aqua 7 from Jimmy Green - I don’t think they do dodgy stuff.

 

[Neeves]

Thanks Jonathan - that’s what I thought - why I was expecting a battle with it. But it was so easy - once I managed to clamp it firmly enough it took maybe 30 - 45 seconds per half link - I didn’t actually time it. Thing is it is Maggi Aqua 7 from Jimmy Green - I don’t think they do dodgy stuff.

As part of my investigation into chains, shackles etc I bought 1m of Aqua 4 and Aqua 7 from JG and had it delivered to our daughter, who lives in Manchester. We were visiting and I simply collected the parcel and stuffed it in the suitcase. This was my attempt at testing chain 'at random'.

On arriving back in Sydney I opened up the parcel to find I'd been sent 2 x metres of A4.

I was quite glad it was only 1m or each, not 100m of A7.

The chain should be marked A7. Look at the portion in the locker, it should be unused and not abraded - unless you have end for ended. The markings are a simple stamp into the link. They are usually at a fixed length so once you find 2 marks the rest will follow that pattern. Sometimes the marking is poor, sometimes really easy to see.

Historically Chinese chain was not marked but historically this was not such a big issue as we all used G30 chain. Things have changed - and I don't know how Chinese anchor chain is now marked. Their lifting chain is marked 80, or 100 - anchor chain - don't know - but it really should be marked at least with a 3 or 4 (I don't know of them selling G70). Maggi chain was well marked, I did eventually get some A7 and A4, and met specification. I have not tested the 'Italian' G70 since Maggi stopped manufacture. There was a lot of flak thrown at Maggi regarding gal quality - I think much of this was unfounded based on expectations of gal life - that were unrealistically too high.

Jonathan

 

[Daverw]

When I’ve tried similar with multi tool unless you can really hold the chain in a vice it does not tough it and if you can hold it a hacksaw would be quicker. Easier with a grinder and slitting disc

 

[stranded]

I haven’t got any scientific comparisons, and am back home now. But the last time I tried to cut chain - G30 or 40, 10mm, it was a bit of a mare - much much harder. This g70 was really soft - starting the cut was just a matter of letting the saw weight grip - none of the bouncing off I expected. It’s really curious. And yet - it’s Jimmy Green…

 

[penberth3]

Well that was a bit of an anti-climax. Thought I’d try a bi-metal hacksaw first. Cut through it like butter. So easily that I now don’t believe it is actually g70, so my wife faces another summer of me sitting at the bow whenever a zephyr raises more that the mere hint of a ripple muttering “it’ll never hold”.

Don't worry about it. We're living in a world where people need £100's worth of power tools to do the simplest job. They must like the bright colours, the yellows, blues, reds and greens.

A new hacksaw blade and the work firmly held, it isn't difficult. You avoid the noise and the mess and save all that time uncoiling and recoiling extension leads.

 

[wonkywinch]

Once you've sawn through the chain, if you did it on deck then I highly recommend Bilt Hamber Korrosol to clean all the rust spots off you boat caused by the metal dust.

Korrosol - Bilt Hamber