Yellow eBay 5 tonne lug crimpers as emergency shroud cutters?

[rogerthebodger]

There is no difference. I all cases material is sheared away from the main body. This was taught HND manufacturing processes, first year. Years later, the same was introduced when I drilled wells and selected drill bits, irrespective if it was a roller cone toothed bit that crushed rock or a PDC bit that milled the rock face, or diamond impregnated bits that ground rock. They all do the same job by shearing material away from the cutting face.

Your shearing blade, does the same, shears material away at the cutting face by yielding the material, as does the hack saw and the grinder.

Different to what I was taught in my BSc degree production /Mech Eng and C Eng

Rock I look at as a non homogeneous material and my main experience is crushing coal or gold ore for further processing

Metals are a much more honigiouns material so can be sheared with greater procision

So we just agree to differ

 

[RunAgroundHard]

Different to what I was taught in my BSc degree production /Mech Eng and C Eng

Rock I look at as a non homogeneous material and my main experience is crushing coal or gold ore for further processing

Metals are a much more honigiouns material so can be sheared with greater procision

So we just agree to differ

Well, obviously you didn't pay attention. What you describe, shearing, hacksawing and grinding, are general descriptions for methods to remove metal, but they all rely on shearing material. If you believe that grinding is not a shearing action, or sawing is not a shearing action, then you are wrong. Your also wrong about rock being non homogeneous. It can be, but it can also be a homogeneous material, please google homogeneous rock if interested. I think you may be confusing homogeneous with single mineral property. Homogeneous rocks are made from many minerals but behave as a uniform material.

 

[rogerthebodger]

Well, obviously you didn't pay attention. What you describe, shearing, hacksawing and grinding, are general descriptions for methods to remove metal, but they all rely on shearing material. If you believe that grinding is not a shearing action, or sawing is not a shearing action, then you are wrong. Your also wrong about rock being non homogeneous. It can be, but it can also be a homogeneous material, please google homogeneous rock if interested. I think you may be confusing homogeneous with single mineral property. Homogeneous rocks are made from many minerals but behave as a uniform material.

So where does the metal get sheared when cutting with a hacksaw or a grinding cutting disk or another metal cutting operation

 

[RunAgroundHard]

So where does the metal get sheared when cutting with a hacksaw or a grinding cutting disk or another metal cutting operation

The teeth of the hacksaw shears a chip of metal off the stock. On a grinder, the grain face in the matrix shears a chip of metal off the stock.

I would hope you agree that turning, milling and shaping are shearing processes as well. Filing is a shearing action.

All shearing processes offer controlled volume of metal removal depending on factors such as force, depth of cut, feed rate, chip removal, lubrication and cooling for the desired outcome, post shearing. Hi Pressure water jet cutting of steel is also a shearing process. They all remove metal mechanically from the stock through a shearing force that is greater than the yield force for the area being cut.

Metal shearing tools such as sheet metal cutters and rigging cutters, yield the steel and shear the steel matrix. The deformed face of the cut gets yielded plasticly into the the deformed face of the cut due to the shape of the cutter. In a silly scenario, if the cutter was blunt and did not break and sufficient force was applied it would rip a chip out the steel, or generate swarf to complete the cut.

 

[rogerthebodger]

I don't see the action of the teeth of a hacksaw of turning / milling tool as being a shear in the same way as the shearing action of a cropping or plate shear as I posted #37

If you gave a blunt lathe cutting tool or hacksaw blade you get ripping of the material that I suppose could look like shearing.

The chips produced on a lathe /milling /drilling deforms the chips and should removes the chips from the workpiece cleanly

You quote "The deformed face of the cut gets yielded plasticly into the the deformed face of the cut due to the shape of the cutter. "

In a proper setup shear the clearance shown in pot 37 need to be as close as possible to reduce any distortion

If you do get distortion your shear blades are not setup correctly that then causes the distortion.

I can remember learning about the metal cutting process and the analysis of chip formation.

During my apprenticeship I worked in both fabrication and machine shops and the hearing process was quite different to the machining process.

I still use the same processes in my home workshop 60 years later

A I said early we just agree to differ

 

[RunAgroundHard]

I don't see the action of the teeth of a hacksaw of turning / milling tool as being a shear in the same way as the shearing action of a cropping or plate shear as I posted #37

Well it is the same, the definition of shearing is consistent, causing material to break away by strain (engineering definition of strain, change in length / original length).

 

[Kelpie]

I'm sure this discussion will prove useful at 3am on a heaving deck as I try to cut through a shroud.

 

[Daydream believer]

I'm sure this discussion will prove useful at 3am on a heaving deck as I try to cut through a shroud.

I would not bother. I know that you are dying to have a go, but i would adivse that you wait until the mast comes down first

 

[rogerthebodger]

To me the discussion about if hacksawing is a shear is pointless as the important thing is to be able to cut away your mast to prevent further damage to you boat.

Any piece of equipment that will do the job is the right piece of equipment

I do have some quick release pins locking my rigging clevis pins to the chain plate that will allow disconnect without the need for any tools (maybe just a hammer

 

[rotrax]

Shades of Deja vu here. We have an argument about stuff that in the real world, on the tools, in an emergency, is totally irrelevant.

I have operated a power guillotine. After cutting, no swarf or metal residue has left the work cut in any amount that can be seen by eye.

The machine 'Sheared' it off. Any metal at molecular level that was displaced matters not a jot for the sort of rough work the cut metal was to be used for.

Make the same cut with a power or hand hacksaw and you get a pile of swarf. Metal is removed, and can be seen to have been removed, from the work.

So, there is a clear and obvious difference to the way the metal was cut in the real, practical, world.

I recently had, with a bloke who was really keen on letting all and sundry know how clever he was, an argument on a motorcycle forum about Bronze welding. After a couple of posts where he rubbished any suggestion that there was such a thing as Bronze Welding, saying as it did not melt the metals to be joined into a molten liquid and therefore could not be considered welding. This, he insisted, was part of his Degree Course and was irrefutable proof that what we were calling Bronze Welding was really Brazing.

However, Sales leaflets from various old school race cars and motorbikes clearly showed the method of joining lightweight tubes with low tempreture Sifbronze was described as Bronze Welding.

He again rubbished this.

He went a bit quieter after I posted this description, by the maker of Sifbronze, the product used for the job.

"Origonal Sifbronze low tempreture rod for Brazing and Bronze Welding".

Despite this evidence he still insisted there was no such technique, coming back to the Scientific definition of welding.

No doubt we were both right, he on an intelectual level, me in the workplace.

After all, if Lotus, BRM, ERA, Ferrari, Matra, Lola, Hesketh made tube frame cars and called it bronze welding, Rickman, Seely, Rob North, Pecket and McNab, Drixton, Dresda, Rotrax plus Norton, Machless and AJS made race frames using lightweight tubing and Bronze Welding, using the term in their advertising, who am I to argue?

 

[Stemar]

Having read a number of arguments discussions about cutting rigging over the years, I've come to the conclusion that it's likely to be far easier to cut through a bronze turnbuckle than work hardened SS wire, though I haven't tried it.

 

[rogerthebodger]

Having read a number of arguments discussions about cutting rigging over the years, I've come to the conclusion that it's likely to be far easier to cut through a bronze turnbuckle than work hardened SS wire, though I haven't tried it.

That may be so but I don't have bronze rigging screws mine are stainless steel so I have to be careful to prevent galling but can cut the split pins easy and hammer out the clevis pins

 

[Daydream believer]

When one cuts a wire with a hacksaw the wires have to be held secure.It is qute possible that the teeth will cause the individual wires to "vibrate".This will either just stop the saw from completing its cutting action or cause the saw to jam in wires that have been cut. It is one thing to hold wires in a vice, but another to hold a wire in one hand & the saw in another. Even holding the wire onto the deck can be a problem as getting access to the wire may well be an issue unless it can be heldover a raised area. Likewise, cutting a large object like a turnbuckle will possibly result in momentary missalignment of cut & blade. Hey presto, broken blade.
Some talk of removing pins. However, once one end of a pin has been hammered flush with one surface there is nothing to hit. So it has to be pulled from the other side. Alternatively, a drift used to carry on knocking it through. Once it has gone so far it will leave one side of the clevice & start to rotate at an angle & jam. This could prevent the other part being released if under load ( sod's law says at least one will be) So then one has to remove a pin which is splayed in a clevis. A lever being a possible solution requiring yet one more tool. Imagine trying to do this with a furler bent over the fitting giving very limited access.
Chopping the wire has to be the best way. Just make sure no one gets caught on the stub left on board . A roll of duct tape being handy to place over the end when clearing up.
Do not forget a couple of fenders on the mast before finally dumping.
One also needs a serated knife for all the ropes. They will not all pull through easily & on the dinghy masts I have lost there seems to be endless feet of the stuff.
When I lost the mast on my small cruiser I was able to pull it back on with the rigging & sails attached. I doubt anyone could do that with a boat much over 20 ft if it happened in a chop & a decent breeze.

 

[Daydream believer]

I have operated a power guillotine. After cutting, no swarf or metal residue has left the work cut in any amount that can be seen by eye.


"Origonal Sifbronze low tempreture rod for Brazing and Bronze Welding".

You could look at it another way---The piece the guillotine cut off WAS the swarf. It was only one tooth in the blade, albeit a big one. It was just a big piece of swarf rather than lots of pieces.

Interesting comment about Sifbronze.The stuff I have is what i use for silver soldering/brazing & it does not melt the metal itself. It is a brazing flux. I have had it for many years. I just use small quants for copper model boilers. I tend to use more modern fluxes these days with lower temperature requirements. If one looks at posh bike frame the "weld" does seem to sit ON the metal rather than IN it as a stick weld does. So perhaps there is leaway in both sides of the debate.
But as I get more failures than successes my opinion is worth very little

 

[rogerthebodger]

When one cuts a wire with a hacksaw the wires have to be held secure.It is qute possible that the teeth will cause the individual wires to "vibrate".This will either just stop the saw from completing its cutting action or cause the saw to jam in wires that have been cut. It is one thing to hold wires in a vice, but another to hold a wire in one hand & the saw in another. Even holding the wire onto the deck can be a problem as getting access to the wire may well be an issue unless it can be heldover a raised area. Likewise, cutting a large object like a turnbuckle will possibly result in momentary missalignment of cut & blade. Hey presto, broken blade.
Some talk of removing pins. However, once one end of a pin has been hammered flush with one surface there is nothing to hit. So it has to be pulled from the other side. Alternatively, a drift used to carry on knocking it through. Once it has gone so far it will leave one side of the clevice & start to rotate at an angle & jam. This could prevent the other part being released if under load ( sod's law says at least one will be) So then one has to remove a pin which is splayed in a clevis. A lever being a possible solution requiring yet one more tool. Imagine trying to do this with a furler bent over the fitting giving very limited access.
Chopping the wire has to be the best way. Just make sure no one gets caught on the stub left on board . A roll of duct tape being handy to place over the end when clearing up.
Do not forget a couple of fenders on the mast before finally dumping.
One also needs a serated knife for all the ropes. They will not all pull through easily & on the dinghy masts I have lost there seems to be endless feet of the stuff.
When I lost the mast on my small cruiser I was able to pull it back on with the rigging & sails attached. I doubt anyone could do that with a boat much over 20 ft if it happened in a chop & a decent breeze.

There is some truth in the high lighted statement.

The issue is that with the mast up and the is some tension in the rigging that is true but once the mast has fallen some /most of the tension in the rigging will be quite slack and the rigging fittings movable.

This has the effect that sawing as you say would b less effective but using a shearing tool would still be effective and as the rigging is movable the positioning of the shear on the rigging would be easier.

As the rigging is now slackish the removal of any clevis pins would be easier the only issue becomes the removal of the clevis locking pin /split pin / locking clip. / locking ring

 

[rogerthebodger]

You could look at it another way---The piece the guillotine cut off WAS the swarf. It was only one tooth in the blade, albeit a big one. It was just a big piece of swarf rather than lots of pieces.

No it's an offcut which can be used for another component

 

[RunAgroundHard]

... operated a power guillotine. After cutting, no swarf or metal residue has left the work cut in any amount that can be seen by eye. ...

Chip removal by shearing is a consequence of the method to remove the metal. Cutting steel with a guillotine, punching or nibbling shears metal and displaces the waste, which may or may not be a chip. Whatever you want to call it, the definition of shearing is universal. I don't know what is hard about understanding shear as a method for removing metal by different processes. If you think that sawing is not shearing and only guillotining is shearing then you misunderstand the term. I would not use the term shearing if I need fine metal removal by a grinding wheel, or accurate stock machining by turning or milling, nevertheless these are all shearing processes. Common names for different processes is accepted. What RogerBodger said in Post 28 to differentiate the processes was wrong but insists that it is right, when this was pointed out.

The thread has delivered information to the OP that suggests the method he is interested in may or may not work, nothing knew there on this forum. Other options have been offered that have been tested and demonstrate that they do work, with links provided to articles discussing tests.

Threads drift because posters take part in the discussion.

 

[RunAgroundHard]

No it's an offcut which can be used for another component

Your absolutism is what is getting in the way of clarity.

 

[rogerthebodger]

Sorry you misunderstand what shearing is all about.

Yes it is a method of cutting mainly metals (you cannot shear brittle materials like brick and tiles)

Shearing is cutting using hard blades passing past each other that exceed the shear strength of the marital to be cut

Shearing a sheep / cutting paper /card with scissors /cutting a hedge with garden shears are all shearing operation

Sawing is cutting by removing of the base material by removing chips with multi teeth

Thick wood would be difficult to cut by shearing but can be sawen easy.

My wifes garden loppers are a shearing action but her chainsaw is a cutting action. Loppers has a limited shear thickness where as her chainsaw does not at its cuts by removing multi chips

 

[zoidberg]

Who here has actually had to do the job? In the dark, and the sloppy confused seas in the aftermath of a gale...? Without losing fingers....?

( diffidently raises hand at the back of the class )