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Jonas
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Awesome, thanks guys! Warren, would you suggest I use some unidirectional cf in the layup? I feel like I could get away with something like half the length, since I'm already using some 0/90, and the uni would primarily be to distribute the point loading the head creates. I found some uni carbon sleeve somewhere online a while ago, but I feel like when the inner tube expanded it all the fibers would just spread apart, so I'd have to use quite a few layers to get it to work. Both points should see about the same stress I'd assume, but the back corner would be pushed up into the head, loading the ends of the fibers along their length. Though now that I say it i don't think it'll be much of an issue. Testing will begin soon... What fabric weight and weave would you guys recommend using?
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wozza
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One thing I have found from testing is that carbon is extremely tolerant to fatigue.(when designed correctly) If the shaft on your project was made from steel or aluminum tube you would expect the cycle of on/off loads to cause fatigue cracking at the point where the shaft joins to the head, so you would have to design in the number of expected cycles plus a safety factor. With carbon if it is capable of taking the load 10 times it will take the load 1000 times if that makes sense. On the downside unlike steel or ally a carbon part gives little or no indication if it has been overloaded, it simply breaks. We actually now use this in the wishbone design, eliminating the rose joints on the inner mounts. The wishbone itself now provides the flex to allow suspension movement. As for layup. If you are new to composites and planning on using some sort of split mould with an internal bladder I would use braided sleeve. As this will expand and contract easily. You could place the sleeve over the bladder, wet out with resin, place in the mould and expand the bladder. If you wrap conventional cloth around the bladder and don't allow sufficient "slack" then the bladder wont be able to expand inside the mould. Perhaps now you are beginning to understand the high cost of the ones at the beginning of your post, you are paying for the R&D that has gone into getting the product to market.  I would imagine they have also designed in a lot of "what if" scenarios as in the real world people tend to use these things for purposes they were not necessarily designed for. Sorry the wishbone development like much of my work is covered by a wagon load of NDA's so I cant give too much away on a public forum. 
Hope that helps Warren
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Jonas
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I thought steel could be designed for infinite load cycles. As long as you keep the load below a given amount it never reaches the fatigue limit. Aluminum on the other hand will always fail after enough cycles, no matter how small the load is. I think titanium's the only other metal that can be designed with infinite load cycles. I was aware that CF doesn't usually exhibit signs of fatigue, and instead fails catastrophically. These qualities are very exciting when you're hanging from the stuff 100 feet off the ground 
Black Diamond has to design large safety factor into their equipment for liability reasons. I, on the other hand, can skirt closer to that line of critical failure. Black Diamond has a test for their CF tools; they have an intern beat them on a curb 100 times on each side, then they retest to CEB-T standards. I don't quite need that level of durability. I understand the principles behind it, but it's not really analagous to the stresses the tool will see during use. I'd rather have it be a little lighter. My parametric CAD professor told me "the best transmission is the one that explodes as you cross the finish line. If it lasts any longer you over-engineered it, and it could have been lighter and smaller." I'd like the ice axes to last a couple races though...
So you'd just recommend the -45/45 sleeving then? I was liking the idea of wrapping it with some 0/90 so the vertical strands would carry the primary load. It'd be awesome if I could find some triaxial sleeving with -45/0/45 orientation, but it's looking like it'll be hard to track down...
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wozza
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Much depends on the facilities, skill level and budget you have available. Its all well and good designing the "ultimate" only to find practical or budgetary restrictions make it impossible to manufacture correctly. Given the relatively small loadings it should be possible to keep the layup simple by using the profile of the the shaft to add strength. Braided sleeve comes in a variety of sizes and can be expanded or contracted easily. If you go up a size, when you pull it to contract it the fibres become more inline getting nearer to uni directional. With some thought you can use this to your advantage. For me I would increase the number of layers in the area where the head will attach, giving a tapered wall thickness along its length. To try and disperse any point loadings. You could add some E-Glass or similar to improve impact resistance if required. I would be concentrating more on how to attach the head to the shaft reliably. By keeping the layup simple you should get much better repeatability, making any testing you do more meaningful and accurate. Obviously this is just my opinion Warren.
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Dravis
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I would like to recommend very strongly that you use at least one layer of kevlar/twaron mix fabric in there... What you're building is a tool for "hammering" some measure of impact resistance seems vital to me .. Also should the CF in the handle break, the kevlar will keep the parts together, which may leave the point embedded in the ice, and you hanging off it still... 
"Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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wozza
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Dravis (13/10/2014)
I would like to recommend very strongly that you use at least one layer of kevlar/twaron mix fabric in there... What you're building is a tool for "hammering" some measure of impact resistance seems vital to me .. Also should the CF in the handle break, the kevlar will keep the parts together, which may leave the point embedded in the ice, and you hanging off it still... The bond between cf and aramids can be brought into question, again needs careful thought and a degree of experience/research.  Warren
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Dravis
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"questionable bond between aramids, CF and resin" ... That is precisely why I recomment using a mixed weave like the Twaron/CF, that way you will have unbroken Aramid fibres running the length of the shaft.
While they may not contribute as much to the ultimate breaking strength of the shaft, they will keep it together, even if it does break, and may still leave the climber something to hang on to ...
Ideally you should run several strands of kevlar Tow through holes in the metal alloy inserts that you bond into the ends of the shaft, in effect tying the metal inserts together with a nearly unbreakable kevlar rope.
Now, I do not know your particular climbing style but, as far as I have seen, most ice climbing is done using loops attached to the handle ends of the ice-axes, so you really need at metal insert at that end too.
When you use an axe and have to place very precise strong blows to anchor the point, the flex of the shaft becomes important too, if it is too stiff, it will be very tiring to use, jarring your hands.
"Sapere Aude"... Dare to KNOW!
The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...
103% of all people do not understand statistics...
Do not adjust our mind, theres a fault in reality :-)
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wozza
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Dravis, liking the kevlar rope idea Only seen a small/lightweight high tensile cable within the shaft connecting the head to the bottom spike as a fail safe. Warren
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Jonas
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For me I would increase the number of layers in the area where the head will attach, giving a tapered wall thickness along its length. To try and disperse any point loadings. You could add some E-Glass or similar to improve impact resistance if required. I would be concentrating more on how to attach the head to the shaft reliably.
Just like how bicycle frame tubes are butted!
I never even thought of it that way! I was planning on doing a layer or two of uni, and finish with a layer of fiberglass for galvanic protection, but completely spaced on how making them butted will make them stronger too. I have a tendency to overthink things and miss obvious details 
I would like to recommend very strongly that you use at least one layer of kevlar/twaron mix fabric in there... What you're building is a tool for "hammering" some measure of impact resistance seems vital to me .. I was still planning on this, but earlier today I was thinking about it and realized the following: If i incorporate a layer of Kevlar that runs the length of the shaft, and the shaft were to break while it was already stuck in the ice, the loading would change to something like this:  In which case the tool would probably slip off anyways. That being said, I'd still like to throw a layer of CF/kevlar weave in there in case I lend it to my roommate and he smashes it on a rock and cuts through the CF somehow. Bottom line: a layer of CF/Kevlar doesn't weigh that much, doesn't seem like it will be hard to include, and won't make things worse. And as long as I'm not making things worse I'm doing okay! Running kevlar tows between the ends seems like a good idea, but I'm not sure how I would get the tows between the two inserts not only taught, but tied off none the less. I considered placing an eyelet on each insert, attach the two with a piece of spectra/dyneema or even basic nylon webbing, epoxy the head in, then twist the bottom insert until it was against the bottom of the shaft, and epoxy it in place. The webbing would still have enough give to let one insert pop out though, thus negating most of the benefits. If I could come up with a way of attaching the inserts so that they're tight inside the shaft I'd feel pretty comfortable climbing on them, since even if the epoxy bond were to fail the inserts would remain inside the shaft and since it's an oval they'd be unable to twist. Currently I feel as though there's two ways that this design can fail that are far more likely than any others: 1.) The CF fails at one of the pressure points on the head. 2.) After enough thermal cycles, vibrations, and impacts, the epoxy bond between the head and shaft fail, resulting the head pulling out from the shaft. I think that with Warren's idea to make the tubes butted, with extra uni and E-glass, the shaft failing is becoming considerably less of a hazard. This leaves the issue of the head pulling out (oh man...), but thanks in part to Brian I think I've got something to help out with that too.  So Brian came up with cutting horizontal slots in the head insert. (Everything you're about to read could actually be a terrible idea, and I just don't know it. It's a good deal of speculation.) I was originally planning on hollowing it out, but this is a lot less labor-intensive and I believe is quite a bit stronger as well. I realized that I could run CF tows through these holes prior to epoxying it into the shaft, wet them down, and epoxy it in. Ideally the fibers would be running DOWN instead of UP, but ya can't have everything. Depending on how many tows I use I assume I'd have to taper the insert a little bit to accommodate their width while still holding 0.01" gap around the edges for optimal adhesion, but I thought I'd pitch the idea and see what everyone thinks. This could pose an issue with galvanic corrosion, so I'll do some research into how well spectra/dyneema bonds with CF and how well it handles compression in a matrix, but I thought it was an interesting idea; kind of like Dravis' idea of tying the two together with kevlar, but...reversed. Shaft flex is something that's been of slight concern. My old roommate plays hockey, and I remember him telling me how the CF hockey sticks he has actually bend when he hits the puck with them. As he swings, the blade lags behind the shaft, then snaps forwards at just the right moment to hit the puck, meaning you have the kinetic energy of the stick, plus the kinetic energy of the blade snapping forwards. Cool stuff! I'm not sure how to factor this into my picks though, it seems like the only way to figure it out is trial and error; keep trying different layups until it feels right. I think I have a decent margin for error though, since most of the ice climbing I do you don't swing your picks like you're driving framing nails with a hammer, but more like you're driving finishing nails. Two or three relatively light taps to chip away a little ice is all it takes; a couple millimeters of ice will support your bodyweight pretty easily. I have a chemistry lab report due in an hour and a half (We weighed water  ...) so I'd better get to work on that. Thanks for the help everyone! Slowly the idea progresses to eventual fruition!
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wozza
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Yep, common in bike frames and many other applications. Slight difference being I would extend it much further down the shaft in a more gradual taper. That way you should be able to retain the flex/feel that Dravis mentions. My background is in the Aerospace/Lightweight Structures sector and as a result the philosophy of "if it has to be there make it do something, preferably more than one thing" is imbedded in me. As mentioned by others these picks seem to have a wrist strap, I assume its main function is to prevent the pick being dropped at a critical moment Why not combine the wrist strap with the fail safe tether. Run the wrist strap up the shaft all the way to the head. That way if the worst happens and the shaft breaks you still have a direct link to the head which is hopefully still stuck firmly in the ice. Warren
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