UKC

In reply to Jack Geldard - Editor - UKC:

it seems strange that they think it would take minutes to produce a injection moulded carbon fibre crab that would be cheap.

for a start carbon fibre i don't think can be injection moulded.

the cost in the mtb carbon fibre frame comes from the material and the way it has to be layered and then baked for x number of hours.

i've seen more CF frames snap than i have aluminium ones and it really doesn't take much force to snap one!

I don't think i'd ever stray from alloy krabs even if i were to be given a whole set of CF ones free of charge.

In reply to the inspiral carpet:

That pretty much echoes my thoughts about carbon fibre - it's very strong in specific directions but known to suddenly fail.
However, I also remember saying similar things about never trusting wire gates, and now I have loads of thos on my rack!

I guess we'll have to wait and see.

In reply to the inspiral carpet: normally CF snapping in that situation is due to it being loaded in a way that it wasn't designed for.

However, if these are designed to be cross loaded, and proven to take the falls etc i'd be willing to go for it..

imagine the weight savings.

but i do agree - i too thought CF had to be layered - and couldn't be injection moulded.. but hey i'm not in R+D/manufacuting. when i think of CF i think boats.

In reply to Jack Geldard - Editor - UKC:
As far as I can see this is merely an experiment by engineers; they just want their next research grant. There is no functional innovation; a super light weight carbon fibre crab still only does the same as a alloy or steel crab. How far do you need to go with lightweight gear? much of the hardest rock climbing has little place for gear, and that's why it's so hard.
These people should start innovating,look at gear that has changed climbing in recent history (cams, sticky boots etc)

In reply to the inspiral carpet: It entirely depends on the type of used. Injecting carbon fibre would involve using short strands of carbon fibre rather than long woven material and similar processes are currently used in the production of bike pedals. This achieves a dense material rather than a thin light one as per your bike frame which is layered up as a laminate which is tricky to do well and labour intensive. However I think you have hit the nail on the head as I think the crux of the issue will be convincing customers that its safe. There have been previous attempts (namely nuts and hexes which were both commercially available,and also I believe a set of cams) all of which were a complete failure despite being strong enough because climbers mistrusted the materials... now if you were to talk to me about powder metallurgy and sintering...

In reply to gethin_allen:

There is a not insignificant factor called cost, too.

In reply to the inspiral carpet:

Carbon fibre laminates cannot be injection moulded and are typically made in the way you describe in the bike example. The injection moulding possibility comes from using shorter fibres that aren't layered in the conventional way. Using short fibres means that you don't have the normal case where the composite is only strong in one of two key directions - it kind of spreads the strength out.

In reply to I Falafelot:

Composite materials are generally more expensive weight for weight. But as I mentioned in the article - the cost of a carabiner is made up of many things, the cost of the actual material is only a fraction of this. The rest comes from tooling/processing time/labour and all the other manufacturing overheads. In the manufacturing industry the aim is generally to try and reduce the steps/number of parts involved as this can massively reduce cost. If it was possible to create a carabiner in one or two steps this might well offset the additional cost of the material.

In reply to Kyuzo: Coming at this from a complete dead start, have you completed FEA onthe cross loading of the one piece crab - I can see a major issue with its design in that the gate, to be a gate must be flexible. But to prevent the gate from opening during cross loading the gate must be rigid or at the least have some way of locking under load like a wire gate (the wires bend but don't fail). Is this some thing you have considered because if not I think that you should ...

In reply to gethin_allen:

Have you climbed any bigwalls? Trust me by the time you've got 80+ gates on you you'll be begging for someone to come up with a 40% weight reduction!

Or on alpine climbs where you take I pare of spare socks instead of two (or none more likely); or only one day of fuel. thats not even close to the weight you could save with this.

In reply to Jack Geldard - Editor - UKC:

A few years ago there was an article in New Scientist about a new source of cheap titanium due to come online and revolutionise all sorts of technology.
Never seemed to happen, and all the russian/ ukrainian stuff I've seen seems to be made a cheaper alloy which lacks rigidity. If the right alloy could be sourced by the right manufacturer it strikes me as a far more suitable material for lighter 'biners.

In reply to Kyuzo:

No sh*t.

In reply to mike kann:
Pretty much my thoughts when looking at the one piece design. Quite frankly the idea of a CF 'biner gives me the fear as I've never liked the stuff (too many broken bike bits and kite spars) but I quite like the design, possibly a keylock type arrangement although that may spoil the looks.

In reply to Jack Geldard - Editor - UKC:

I don't think I'd fancy carbon climbing gear

http://4.bp.blogspot.com/_V54WWNeyyp4/SO-MAdRdGbI/AAAAAAAAAvc/wtxiK5HNL8Y/s...

I've spent too much time looking here

http://bustedcarbon.blogspot.com/

In reply to Reach>Talent: If this stuff ever does come on to the market i dont think you need to worry too much about it breaking. The testing climbing gear goes through is pretty stringent.

In reply to remtherockclimber:> (In reply to mkean) If this stuff ever does come on to the market i dont think you need to worry too much about it breaking. The testing climbing gear goes through is pretty stringent.I'll wager they said the same about MTB frames too...

In reply to mike kann:

This is a good point, the one-piece crab would have to use a 'captive eye' design where the quickdraw sling is trapped (like the old DMM Mambas) so that the crab can't be cross loaded. For more flexibility you could also produce the more conventional design with a wiregate.

In reply to hal:
I've done some multi pitch but I haven't done any "big wall". Not entierly sure of the definition, surely you do it in pitches and strip gear as you go so you only need slightly more than a standard rack.
And anyhow, if you take 80 of the lightest conventional crabs, then knock off 40% you lose about 800g not an enormous amount, considering what people used to climb in/with.

In reply to gethin_allen:

People 'used to' climb with extremely few pieces of gear. (E.g when I started I used about three krabs and two slings.)

In reply to mike kann:

Judging by the response in this thread, it seems getting climbers trust will be a major barrier! I wonder what could be done to convince people. Perhaps get well known climbers to take enormous lobs onto the new gear? Or send a free crab to anyone who creates a user-made video of themselves lobbing onto the new crabs...

In reply to Kyuzo:

with a sh1t load of alloy crabs as back up just out of frame? :0)

In reply to the inspiral carpet:

Heheh, yep. Otherwise no one would want to be the first to try it!

Can I just say I'm an Aerospace Engineer and I also used to (until 2 months ago) work with composties, and composite design. Whilst the idea of it will be revolutionary should it suceed, I have very little confidence that it ever will.

With-out meaning to rabble there are a few facts that people need to be aware of.

Carbon and other composite fibres get the majority of their strength in tension, that means when they are pulled end to end. The remainder of the composite is made up of a resin system, typically Epoxy although can be a wide range of resins and mixs.

I would throw out the idea of Injection molding, because in order to acheive it, the resin would have to be hot injected, keeping the resin at a lava type condition with-out post curing it will be difficult so a high amount of presure will be required, in order to get the strength the material (i.e the fibre part) will have to be placed into the mould to ensure the fibres are running in the correct orientation. The percieved idea that I think is suggested is chopped short strands of fibres and injecting them with the resin this method simply does cut the mustard in the strength dept.
When you attempt to inject the resin the fibers will move and the resin wont coat every strand of fibre therefore your going to have quality issues that will ultimatly screw any chances of CE rating, so unless you want to sell in the Eastern block, you won't have any customers. The alternate is to over mould the crabs and finish them back to a good surface finish, quality and again the strength will be comprimised.

The next option is to use a dry lay-up pre-impregnated system, which would involve skilled laminators placing material coated in resin into a mould layering up the different layers these are then baked as such and held under pressure to consolidate the fibers and ensure that the resin flows to all the fibers. Using this method the idealist would envisage making them hollow then you'd have to convceive a method for pressurising the cavity, inside using a non - porus membrane to stop gasses esaping from the mould or bubbles in the crab. This is known as bag moulding. In such a small space this would not be possible, therefore you would be looking a making the crab solid, by which point the weight of resin you would have to use to make the finish of the crab acceptable would be almost as much as the metal counterpart. The cost would be emense because its nearly imposible to automate much of the process.

No climbing company is likely to take this on as the strength of each component is subject to variations such as the inherant skill of the laminator , the room temperature and humidity he prepared the mould in, this would mean in such a mission critical environment, no company would take the risk!

Whilst in a book you may be able to obtain tensile strenghts of 3 times that of hardened steel in reality you looking at around 70GPa which is acheivable with good alloying.

As for open gate crabs - not on my rack thank you!! The flaws are obvious.

Whilst it is possible to achevie great results from mountain bikes and even ice axes this is becuase the cavities inside them are large enough to be able to get an inflatable silicone bag that presurises the component from the inside, this means that the parts are considerably stronger, in addtion to this the relative impact forces are low, compared to that of a crab, neither have to sustain heavy abraision, whilst the axes does its not anywhere near as critical and the failure would be detectable.

I would suggest that the scientists / dreamers conduct a FMEA analysis before wasting any more of their time, this will conclusive prove to them that the chances of things going wrong vs the ability to detect problems vs the effects of something going wrong means that companies will laugh you out of there office if you get that far!

--------------------RANT OVER---------------------------

In reply to Epic Adventure: As another aerospace engineer (not a composite design specialist, mind) I would agree with those points. In addition I would be sceptical about any composite karibiner's ability to maintain its properties under normal conditions. A quick glance at my rack shows a great deal of surface damage to the alloy equipment. This will have very little if any impact on the strength of the item.

Carbon fibre and some matrix materials can be relatively brittle. Often knocks and blows can introduce Barely Visible Impact Damage (BVID) to aerospace composite components reducing their strength. Obviously climbing equipment is subject to very rough handling so this problem may be even worse for this application of composites.

As an aside, it would be interesting to see how much carbon composite ice axes are effected by BVID. The inside suface of a tubular handle may be significantly damaged by a blow that leaves very little sign of damage on the outside - significantly reducing strength.

I wouldn't dismiss the idea out of hand but I would want to see a lot of testing before I hang off one of these karibiners!

In reply to Epic Adventure: Hehe... Imust admit, you have put into words most of my concerns with the whole process. Kyuzo - I see you are a third year engineering student - I presume your supervisor does not climb and that he suggested you look at composites? I think it is one bridge too far. All very well in principle but...

Epic - I presume coming from an aero background you have some experience of sintering blanks formed from powder - I have always thought that this might hold serious potential for advances in climbing gear butas I have no experience of the process Idon't know this for sure. Although the actual processappears initially expensive, I'm guessingthat there could be a seriouspay off in terms of lack of finishing required and material wastage. Especially components which experience compressive loads such as nuts and cams. What are your thoughts?

In reply to Epic Adventure:

Cheers for the thorough response!

I'll try not to go on too much, because the details of the project are on the website www.crabdev.co.uk but just to try and reply to a few things:

In terms of injection moulded short fibres - new grades and combinations of short random oriented fibre composites are being produced all the time - with modulus and tensile strength approaching that of 7075-T6 but with around half the density. One of the latest, 90HMF40 from Victrex, was released less than a year ago and has a modulus of around 45GPa and UTS of 350MPa, density 1440 kg/m3 (compared to 7075-T6: mod 70, UTS 500, density 2880). As it is it would perhaps be slightly low modulus and might now hold it's shape well enough, but 5-10 years ago we were a lot further away than we are now. Still, I wouldn't discount this material until it's been tested.

The main problems I could think of were: toughness, wear, damage tolerance and damage detection. I looked at some research into improving composite toughness - but it appears using injection moulding of short fibres avoid a lot of the problems (no delamination), but only testing will reveal if the materials are up to it. The other issues will need solutions - for wear perhaps a low friction coating or additive, damage tolerance can only be tackled with testing to find performance (and then improving if necessary), and detection might involve an ultrasound checking service for suspect gear.



I'm not sure what you mean here, are you talking about modulus or strength? Carabiner aluminium is roughly 500MPa UTS and 70GPa modulus. I agree that textbook values for UD or multi-axial laminates are not that useful because the crab won't just be pulled in one direction. But short quasi random oriented fibres give very close to isotropic properties.


I know it's a bit far fetched maybe - but I envisioned a sport crab where the sling is held captive in the quickdraw (like the DMM mamba ie. crab cannot be cross loaded, in this case, understandably, the EN requirements forgoe the need for cross-loading testing) with a skinny flexible gate to prevent the rope from just falling out. You would have to overdesign the body to account for the fact that's it's weaker in the open gate mode, but it might make for a nice smooth clipping crab (though probably not lighter in this case).

in addtion to this the relative impact forces are low, compared to that of a crab, neither have to sustain heavy abraision, whilst the axes does its not anywhere near as critical and the failure would be detectable.

I would argue that axes do have to handle heavy abrasion! But you're totally right about the criticality of the crab. And as composites tend to be a lot more rate dependant it might be necessary to have new standards to check their safety in a sudden impact climbing fall (current EN standards require only static pull tests). Apart from that, testing a sample out of every batch in the normal way would still give a good guarantee of consistent strength.

Anyway, if you feel like a reading my (big boring) study on it, it's all online at the website! You'll probably find a lot of it a bit obvious if you're from a composite background, but I was starting from zero knowledge of composites for the project so please forgive the lengthy background info.

In reply to Jack Geldard - Editor - UKC:

I just think..a sudden hit and an alloy one would probably bend, definately before breaking anyway. Don't see the CF ones doing the same somehow? Think , especially as i'm still a relative novice with climbing, i'll stick with the tried and trusted and proven ones

In reply to Jack Geldard - Editor - UKC:

Another factor in this day and age must surely be the environmental impact (if any) of using cf over alloy?

In reply to Jack Geldard - Editor - UKC:

Slight tangent but on the question of reducing weight but maintaining strength why is titanium so expensive?

In reply to Trangia:

Titanium is more dense but also stronger than Aluminium. One problem with Titanium is that, because it is so strong and also more dense than aluminium, if you wanted to save weight the crab would have to be very thin - which is not suitable for the rope to run over. If you made the rope radius bigger, then because of the higher density of Titanium, the crab will be heavier anyway. This problem was described to me by a gear designer who worked at Kong in the 80s when they were experimenting with new materials.

There may be ways around this however - like only making a small part of the crab have sufficient radius. But this is still tricky because there's no guarantee of where the rope will run.


In reply to tommyzero:

Yes, this is an important point. Aluminium is fairly easily recycleable - whereas most composite laminates are not. However - a short fibre thermoplastic composite could simply be remelted much in the same way as a metal.

In reply to Trangia:

Titanium is very difficult purify after it's been dug up.

In reply to Jack Geldard - Editor - UKC:

Add my pennysworth. I build machines for the technical textiles market and I have been on the outside of developments in 3d braided composite products.

I would be speaking to any research/development team in textiles ( or modern materials)at places such as Manchester University ( I can give you names if you email me) who have been doing such work.

You never know what you might learn.

In reply to Kyuzo:

Thanks I hadn't realised the thickness/rope problem. I suppose quick draws could have a thin titanium krab for the wire/bolt end (thickened where the sewn tape passes through) and a normal wire gate aluminium Krab for the rope end? Whether the resulting weight loss would be worth the effort might be debatable though.

In reply to Jack Geldard - Editor - UKC: We looked into carbon fibre for Krabs a number of years ago. What put me off was when I took hold of a block of carbon fibre (4cm square) and rubbed it against a granite surface for less than a meter, approximately a third of the block wore away. I think this is the biggest challenge to overcome.

In reply to Trangia: Titanium is actully one of the most common metals on earth but it is an absolute pig to extract. Whats more it forms in a powder which then needs to be formed in sheets. The trouble with this is that it oxidises badly so it needs to be done in an inert gas such as Argon which is expensive. This includes forming and welding, so all round it is a pain to process and consequently requires skilled (read expensive) workers, and a lot ofpower to do so...

In reply to Trangia: The other issue is flex - Titanium isa curious material in that it is light, strong (weight for weight) and flexes well. If youhave a very thin piece of Ti itacts like a spring - infact there were earlysuspension bikes which relied on the flexof the chainstay tubes to provide the movement for the suspension unit! I don'tknow what Kong were looking at at the time,but I suspect that it was not sintering which can produce low volume but high cross sectional area pieces which could potentially include a large radius at low weight. I can see there being major applications but I am not involved with sintering so don'tknow the fine detail So far it is mainly used in the aerospace industry but there are instaces of powder metallurgy (parts made from powdered metal) - I believe Swedges/micro stoppers are formed from powder and then filled. The advantages of powder metallurgy are the production of highly complex shapes with out the use of forging which uses heavy machinery and is an iterative process (i.e. hit it till its the right shape), the inclution of other metal blanks into the same part (could be used to produce different wear characteristics) low tooling costs and low material wastage. In compression the resultant parts are nearly as strong, but in tension they are less so, which is where sintering comes - it involves heating the
preformed blank to a high temp which reforms the bonds between the metal particles... I can envisage uses likethe forming of cam lobes and nuts, as well as other items. However it is a highly specialised process and would require an expert whowas passionate enough about climbing...

In reply to Epic Adventure:

what are you on about? the top manufacturers will surely just make them out of carbon fibre barstock in the following steps:

Step1. Cutting to length
step 2 bending to rough shape
step 3 forging into shape - ise a big press to force the cabon fibre into the correct shape
step 4 clipping off the excess carbon
5 rumble to polish
6 add a wire gate....

shouldn't be too hard to adapt the current presses to use carbon fibre for a quick weight saving.

In reply to petellis: Troll

In reply to mike kann:

>...I presume coming from an aero background you have some experience of sintering blanks formed from powder - I have always thought that this might hold serious potential for advances in climbing gear ...Especially components which experience compressive loads such as nuts and cams. What are your thoughts?

BD Swedges are made from sintered steel IIRC.

As for composite krabs. From a position of limited knowledge I see no particular reason why it can't happen though I doubt we'll see them any time soon. Fiber reinforced, injection moulded plastics are all around us already. Resin infusion into a mould packed with aligned tows would produce a strong structure and would likely prove very repeatable. It may also not prove too difficult to automate since the tows could be drawn into the mould and aligned using a vacuum while dry then pre-tensioned before infusion.

As for people worried about 'random' failures of carbon composite structures, part of this is due to the way these parts are traditionally made and part of it is due to the fact they're often used in structures that are pushing the boundaries of weight/performance. Often pushing a little further than is wise.

jk

In reply to M. Edwards:

Yes, this is definitely a big one. Especially when you consider that this can be a problem even with the aluminium used currently - well used crabs tend to get grooves in the rope bearing surface and eventually they will wear out. Most polymer resins don't even come close to the the hardness of aluminium alloy and would wear out a lot faster.

However, this is something that's being researched a lot because the composites have so many industrial applications - as a result it is improving a lot. There are methods that have already been developed such as additives and coatings - if I recall righyly, one method gave an order of magnitude imrovement in wear characteristics. Then there may be other options, such as putting a layer of metal or other material to act as a protective sheath.

What company were you involved with? Or was this independant investigation?

As an aside, I think Rewind in Carn Vellan is the most terrifying looking climb I've ever seen, dark, damp, massive sharp boulders, no gear, 45 degree roof. Nice one!

From a classical engineering perspective, tubular construction would be the obvious way to make light and strong karabiners.

I can't really be bothered researching, but I believe that Simond in the mid 70s may have been the first to market a tubular karabiner, although this may have been intended for aid climbing only. (They also produced aid climbing krabs without locking gates that would open easily under bodyweight.)

Black Diamond (or Chouinard Equipment, as was) have also gone as far as manufacturing prototypes of tubular krabs, but I'm not sure if these were ever marketed.

The problem with all of these designs is that although the krabs are fine in pristine condition, the tubular components are very easily dented during normal handling, and even very slight denting can produce alarming reductions in strength. At present, no tubular krab designs are in production, I think. (Feel free to prove me wrong.)

Anyone who has used carbon fibre components will know how fragile they can be when stressed in ways other than designed.

I'm very sceptical about this article. Can you tell?

By the way, no less than Denny Moorhouse himself told me that riveted construction for ice axes was now obsolete, and that future designs would be assembled using hi-tech adhesives. ..

However, this was in about 1977 ...

CJ.

In reply to Anonymous:

>

This is really interesting, I'd not heard about these being produced before - how did you find out about it?


I think jkarran mentioned a very relevant point about this above: "As for people worried about 'random' failures of carbon composite structures, part of this is due to the way these parts are traditionally made [by hand - therefore inconsistent] and part of it is due to the fact they're often used in structures that are pushing the boundaries of weight/performance. Often pushing a little further than is wise."

So long as you design for safety foremost, and do sufficient testing, then there shouldn't be a reason to have these concerns.


Rivets are only just beginning to be phased out in the aero industry, the indutry is moving more and more towards weight savings (hence fuel and environmental savings) with composite materials - and these materials are well suited to adhesive bonding. Adhesive bonding spreads the stress in the materials better and avoids the stress concentration due to drilling holes in the sheet materials.

Although, having said that, the Lotus Elise chassis (well known for being very rigid and strong) is made with bonded aluminium - so adhesives don't just suit composites. I wouldn't be surprised if his prediction came true still (if a little later than expected). I would imagine it might shave off a small amount of weight and could be a much stronger way of attaching the head - probably a fair bit more expenssive though, perhaps this was what held it back? I'm sure the technology is a lot more cost effective now though.

In reply to Kyuzo: The trouble with most bonding processes is that the adhesive needs to cure which takes time i.e. costs money!

In reply to Kyuzo: It was an independent company, backed by a very wealthy millionaire who was interested in climbing gear innovation. Sadly, he died and that was the end of the research and backing. Our research into the E-fix and later the ENP was also part of this research. Our findings in the E-fix was it did not work when the hole became "coated/polished" with use and got scraped, and the ENP was unable to be accepted into the climbing gear manufacturing world, apparently no money in it.

Yep! Carn Vellan is a very special place... such a shame it was surrounded in controversy and as a result seems to be not on the radar anymore, awesome place I agree.

In reply to Jack Geldard - Editor - UKC: Get it right, tick all the boxes and it is a very big market for the first successful entrant. Climbers being such weight obsessed gear freaks

In reply to Jack Geldard - Editor - UKC:

By the way, if you click through to the linked website there's an interview with Chris Rowlands from DMM, about climbing gear design/production which might be of interest to the gear nuts out there.

In reply to Anonymous:



I've got some SALEWA krabs that I've always believed were tubular. They are an oval section and rated at 2000. Am I wrong...?

In reply to jon:
Hollow karabiners were introduced by Salewa in 1970 so you are right. I´ll ask down the wall in Munich this afternoon if anyone knows whether there were problems with them.
Jim

In reply to jimtitt:

...too late - I've been using them ever since! Be nice to know, though. Just uploading a photo of one as we speak. I suspect a lot of people have them...

In reply to jon:

By the way, I've always thought that they would be quite weak if clipped into a bolt, and therfore always used them at the other end of a quickdraw or for trad climbing - used with tape, ie a friend etc...

In reply to jon: We had/have(?) a hollow stainless steel Krab, thought this would be great for sea-cliffs, but the gate was made from alloy, so the same electrolysis happened when the Krab was wet and left in your rucksack (a common problem with mixing hard metals with soft) the softer metal "sacrifices" itself and flakes away. White spots on the metal surface are the tell-tale signs this is about to start. It can happen to cams too.

In reply to M. Edwards:

It says here: http://www.simond.com/projects-20-GB.html that Simond were making tubular krabs in 1948 !!!

CJ.

In reply to Jack Geldard - Editor - UKC: iy

In reply to Anonymous:
On the French version of their website it says "lightweight" (léger) so obviously something a bit wrong in the translation there!

In reply to jimtitt:

No, it does indeed say tubulaire... I still find it hard to believe though!

http://www.simond.com/projets-20-FR.html

Any ideas on my SALEWA krabs, are they safe?

In reply to jon:
But on http://www.simond.com/legende-6-FR.html it says léger!!!!!!!!!
The plot thickens.

Can´t find anything on the net about the Salewa krabs but then we are talking a bit pre-web here. Send me one and I´ll pull test it if you want, I´d think open-gate would not be too good!

Jim

In reply to jimtitt:

No, I'm afraid it doesn't, go back onto this, then click on 'innovation'. It does say 'tubulaire'.

http://www.simond.com/legende-6-FR.html

As for ths Salewa krabs, I've only got 2 left - and I really like them... thanks all the same!

Maybe I need to go down to Simond and see if they've got one in their museum. Trouble is, last time I asked them for something, it was to take out advertising space in my topo for Barberine. Dominique Marchal said no, so I went to Mammut who said yes... Still be interesting, though. Jon.

In reply to jon:

The Salewa webite suggests they came out in 1970: http://www.salewa.com/uk/4/25/history.html I'd have put it later but perhaps they were not distributed to the UK initially. I remember mutterings about the safety with bolts or pitons, "Salewa collapsables", but whether this was any more than pub talk I don't know.

I'd have thought that you could stretch to a couple of new Heliums?!

In reply to Jack Geldard - Editor - UKC:

The biggest issue with using carbon fibre in this scenario is the ability for it to hide defects.

Aluminium and steel are both ductile metals, and as a result, a degree of deformation would occur before failure (unless it's very cold for the steels). This should be easily picked up on gear inspections.

Carbon fibre materials tend to fail with less warning, as neither component is ductile in nature. Some toughening is possible by post-crack fibre bridging mechnisms, but these tend not to happen in the standard carbon fibre (pre-preg weaves, filament wound, 3 directional etc.). The injection moulded plastic have this sort of toughening, but the inherent strength of carbon fibre is due to the directionality of the fibres in the epoxy, and isotropic distributions lower the maximum tensile stress considerably.

In reply to Jack Geldard - Editor - UKC: Alternative materials such as plastic for hexes have been around since the nineties. I know people who use poly-hexs, never seen anyone use the nuts though.
see top of list in orange type on needle sport link.

http://www.needlesports.com/nutsmuseum/morenutsstories.htm

here too http://www.spgear.org/gear/930/poly-hex.html

this is good for images http://www.jeejo.com.au/altitude.htm

carbon fibre? i,m not so sure

In reply to Crofty:

I bought a Peck glassfibre and nylon chock in 1971. Used it a lot.

CJ.

http://www.needlesports.com/nutsmuseum/morenutsstories.htm

Brilliant picture of all the cams...

A thought: Cams from carbon fibre with metal on the rock contact edges, trigger plastic and the flexible cable stainless steel? The perfect set up?

Anybody willing to make a prototype out there, I would be willing to test it on a daily basis out on the crags.

In reply to M. Edwards: I sure somebody has made plastic cams... can't remember where I saw them though...

In reply to M. Edwards: I must admit I do have an idea for a high expansion rate cam system, but I'd haveto kill you if I told you about it... am seriously thinking about prototypes at the minute... will give the carbon cam some thought...

In reply to mike kann: Seriously, keep me posted, would love to help.

In reply to Alex T:

As Rolls Royce found out, to their detriment, when they tried to make carbon fibre fan blades for their aero engines... although the effects of firing frozen chickens at them was anything but barely visible!

Further thoughts: There would have to be metal also incorporated into the cam at the cams contact with the axle too, this would be to protect the carbon fibre from friction wearing. I can see this type of set up being more beneficial on the larger, and at the moment, heavier cams that exist today.

In reply to M. Edwards: Shall do. Have had it on the back burner for a while but now looking for a steady income so looking at working on it a bit... I'll see what I come up with... I did work on a project with HB shortly before Hugh had his accident and ended up pretty much withthe Metolius supercam but I have in idea to make it loads better and patentable. I did it as a studentand wasn'tthinking laterally enough at the time and I always found the design clunky and a bit rubbish. Butnow the thoughts have crystallied a bit, and IF I got it right, man oh man...

In reply to M. Edwards: Look up IGUS bearings. Although I think the issue wouldbe one of point loadings rather than wear...

In reply to mike kann: Kann Kams? I'll buy a set.

In reply to mike kann:

The bearings look the business. Keep out the dirt too.

In reply to M. Edwards: Would be great to have a sealed unit that require no lubrication, as all cams do today. Always a pig to clean cams, messy job and I have been told by a Royal Naval Helicopter engineer, that WD40 has been banned for use on helicopters because of carcinogenic worries. But they did use gallons of the stuff.

In reply to M. Edwards: Trouble with sealed balls is they take up space, and also if they are balls they don't take a great deal of torque of which there is plenty. Also bearings don't behave that well in reciprocating use unlike plain bushes likethe Igus units. Added to this bushes are cheaper than Fishponds hooker...

In reply to Kyuzo:

I'd be a bit careful about the new high strength reinforced thermoplastics that are currently being advertised. The material properties you see advertised will be the best the material can do when the bulk of the fibres are aligned along the direction of loading. This can be easily arranged in a test specimen but a lot more difficult to arrange in a more complicated 3D shape with limited options for the positioning of the injection point of the plastic into the mould. If you're really interested I would ask the manufacture for strength data both in the flow and cross flow directions, it's likely to be very different.

The other thing I'd be careful of is their impact strength. I've got some test plaques of this sort of stuff on my desk. I tried snipping them up with some side cutters a while ago and the plaques shattered, they were very brittle.

Someone mentioned 3D weaving techniques earlier and this was my first thought. I don't see why you shouldn't be able to make a tube with the lightweight core, a lot of uni directional fibres running along the axis of pull and then some 45/45 fibres wrapped around the outside to take up the off axis loads and hold the whole lot together.

I agree with the sentiments of others that injection moulding a matrix around the fibres is unlikely to work. My guess would be that the fibre density would have to be reduced to a point where the resulting composite has little advantage if any, over aluminium.

Good luck!

one issue being ignored is fundamental in design - that is should you really be trying to tweak an existing methodology and its associated products to make it work with a different material?

What I'm trying to say is you need to look at - is a carabiner really the only way to get to the desired result?

more radical use of materials in other solutions may not suit all historic climbing situations but why is sport climbing stuck with a 50year plus concept?

In reply to Removed User:

Please use the correct terminolgy - 3d braid not weave. Weaving is defined as the pattern of interlacing a warp and weft in a woven fabric.Braiding is the interlacing of three or more threads in such a way that they cross one another in a diagonal formation. There is a huge difference.

As an example carbon fibre bike frames are braided not woven.

Carbon fibre propellor blades are braided not woven - been around for 20 plus years.

Anything in a tube is usually braided.

In reply to Jack Geldard - Editor - UKC:

There's a lot of talk here about bike frames and bars breaking. Now, this is true, but these items are not designed to be indestructible in a crash, whereas the crabs will be designed to put up with falls. That's an important difference. Steel frames bend in a crash, however the mode of failure of CFRP is always more dramatic, and yes, possibly more dangerous. But a bike frame is expected to fail under certain circumstances, and this will be designed not to. That's the crux of the matter.

A serious but overlooked issue here is the problem of sub critical damage which is very hard to detect on CFRCs - basically you could be walking around with a perfectly nice looking crab which is mush on the inside. Damage like this is very easy to cause and a really significant problem for aviation - the typical scenario is someone drops a hammer on a panel, thinks nothing of it because the panel looks fine but undernearth the top layer there is significant delamination. This would cause a good looking but damage crab to failure holding a fall.

What you really want here is silicon carbide reinforced titanium MMC seriously strong and light weight, nice fatigue and damage properties but a bugger to make right everytime...

In reply to Anonymous: My friend Bob has a few hollow tube biners. I can't remember who made them, although Simond does sound familiar. He uses them to rack his wires, and they are amazingly lite!
Jon

In reply to cmsg:

These are just being used to illustrate some of the products that are now made from carbon fibre, and it opens the mind as to what is possible.