manuel Posted November 4, 2021 Report Share Posted November 4, 2021 5 hours ago, Adam@TartyBikes said: Functional fitness / strength is always impressive I find, seems to build less bulky muscle. Just meant that Dave is a beast! Tested one to 200kg and it holds fine. The eyelet at the 'rim' end has deformed a little though. The spoke stretches by about 3mm at this tension. Normally you'd build an MTB wheel around 100-120kg. The jig below has a 2:1 ratio so the steel spoke is half the tension of the rope one. Also tested spoke tension increase after standing on a bike - it was too small to measure. So I think my estimate of 200kg maximum spoke tension during riding (having started at 120kg) is way over what they'll actually see. What about where the spokes cross in the wheel build - will they be ok with the friction/movement as a stranded thingy? other than that they look a mahooosive ball ache to actually do the wheel build with! I’m assuming you might have to make a custom spoke key and spoke holder to stop them just spinning round? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 4, 2021 Report Share Posted November 4, 2021 Apparently so - this stuff is used in sailing rigging, so it's designed to be abrasion resistant. The eyes will need to be longer to allow a spoke key to fit on (though I have got nipples with a 'double square' so you can build from the back - https://www.spoke-store.com/photos/original/sapim-double-square-secure-lock-alu-nipple.jpg) and I'll need a way of stopping them rotating (easy enough). But yes, creating the spokes accurately will take a long while - the reason Berd charge so much I'm sure, given the relatively low material cost. Quote Link to comment Share on other sites More sharing options...
forteh Posted November 4, 2021 Report Share Posted November 4, 2021 Shouldn't be too hard to knock up a jig to get them all the same length if you're bonding them in. Just put the spliced end over a peg and have the nipple set in a clamp to set the length. Working out how much shorter to make them to allow for the additional stretch might take some time though. Quote Link to comment Share on other sites More sharing options...
isitafox Posted November 4, 2021 Report Share Posted November 4, 2021 Really hope you pull this off Ads, also really intrigued to see the dampening effects if they ever see a trail! 1 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 5, 2021 Report Share Posted November 5, 2021 11 hours ago, forteh said: Shouldn't be too hard to knock up a jig to get them all the same length if you're bonding them in. Just put the spliced end over a peg and have the nipple set in a clamp to set the length. Working out how much shorter to make them to allow for the additional stretch might take some time though. Yeah thats the plan, ish, though one end of the jig will need to be the hub of course! I think I'll add a good amount of load to the splice / bury at the hub end before making the rim end. Should bed in the splice sufficiently to make any stretch consistently elastic. At the moment it looks like I'll be able to figure out stretch amounts using the jig I made. The idea behind using the double square nipples is so you have an extra 2mm to play with too, so that will help out a little. If I get time today I'm going to try rolling a long thread onto a spoke, coating it with epoxy, sliding the spoke straight inside the rope, adding a coat of epoxy to the outside and then heatshrinking over the top of the lot. Hoping this will create a high enough friction - if only mechanically rather than by adhesion - to allow much easier building and spoke length 'adjustment' than having two buried splices. Quote Link to comment Share on other sites More sharing options...
Al_Fel Posted November 5, 2021 Report Share Posted November 5, 2021 Would it be easier to do two spokes at once? (From the rim through the hub then back out the hub to the rim again) I know this might mess tensioning up etc (Could possible sort that with a couple of knots at the hub?) but it might make it easier? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 5, 2021 Report Share Posted November 5, 2021 I looked at that... I think the torque from pedalling and braking might be affected significantly as only one of the pair would be pulling tangentially then (hard to explain). Also knotting this stuff really ruins the properties - can't remember exactly but it reduced breaking load by at least half! I think Berd have put a lot of time and effort into these. All the conclusions I'm coming to seem to match what they've done... 2 Quote Link to comment Share on other sites More sharing options...
forteh Posted November 5, 2021 Report Share Posted November 5, 2021 Surely wouldn't it be simpler to not have to splice the spoke directly to the hub or is it not that much more fiddly for a one off? Admittedly it does look far, far nicer than the dogbone bits that berd use (I think they just use a length of dyneema soaked in a cyanoacrylate to make it ridgid). Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 5, 2021 Report Share Posted November 5, 2021 Its no more fiddly. And looks a lot less of a bodge as you said. I think Berd do it the way they do to ensure customers don't have to do a splice, and it allows them to set the spoke length at the factory. I'll try soaking in superglue today as well then... Quote Link to comment Share on other sites More sharing options...
forteh Posted November 5, 2021 Report Share Posted November 5, 2021 Yeah, obviously berd are doing it because they can't let the customer do the splice, it would be like selling a kit of tubes and a tig welder instead of a frame Are you still having to add the extra chamfer/deburr to the hub if you're not having to push the full spliced head through the spoke hole? I think the methacrylate with a keyed spoke and a heatshrink wrap will work quite nicely. If you're not familiar with methacrylate, think of it as 2 part epoxy superglue paste, working time is very short and it cures hard enough to machine if need be. 1 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 6, 2021 Report Share Posted November 6, 2021 Not sure about the deburr, but I'm doing it anyway to be certain. I tried some glued spokes and wasn't really keen on the results. I would also then have to find a way to stop the spoke rotating while building, that didn't involve gripping it with mole grips or something equally crude. Then I remembered silver soldering! My first 3 attempts, straight after soldering / brazing, covered in flux. This is much less temperamental and a lot easier than welding, plus gives a much neater result IMO. Flux removed and scrubbed with wire wool. Love the way the silver flows! Checked the condition of the rope where it went through an eyelet. This had done 10x cycles to 140kg and a couple to 200. No fraying so I think that's acceptable. And finally, loaded up a soldered eyelet to 200kg, then have left it at 130kg for the weekend to check it doesn't fail. 4 Quote Link to comment Share on other sites More sharing options...
forteh Posted November 6, 2021 Report Share Posted November 6, 2021 Yup the silver soldering gives a far nicer finish and I'd warrant it's probably a stronger structure than welding such small section stainless. Also gives you a more useable flat to grip with a spanner that you'll naturally make I think the deburring on the berd spokes is because the hub holes need to be opened out to get the full splice through, I would have thought that the default j bend spoke hole chamfer might be enough. 1 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 11, 2021 Report Share Posted November 11, 2021 Changed tack a bit on the eyes... Turns a spoke into one of these in just over 30 seconds. Blob of solder, away we go! And a max load test, just for you @forteh... This was a really old and haggard section of rope too - a bit frayed from being re-used at least a dozen times, and the splice burying was way too short. Still, the spoke necked down to 1.6mm from 1.8 and snapped before the rope snapped or the splices slipped. Time to sort out a batch of eyes and get cracking on making spokes! Quote Link to comment Share on other sites More sharing options...
forteh Posted November 11, 2021 Report Share Posted November 11, 2021 What kind of f**king wizardry is that spoke jig! The results look like the videos you see of coil spring winding machines but obviously without the automation, very impressive repeatablilty though. Wonder if there is any HAZ from the soldering? I would suspect not but it would be interesting to see if an unsoldered behaved in the same manner. Do you know what load the spoke end snapped at? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 11, 2021 Report Share Posted November 11, 2021 Ha. Thanks dude. Pretty chuffed with that one considering how f**ked the jig looks. I started at 210kg then just kept winding - it started to feel a bit weird almost immediately so I don't think it got much over this load. One of these spokes has a claimed max load of ~330kg. So I think there might be an issue due to excessive heat... I think I've been getting the spoke up to about 800-850 degrees based on the colour - the solder should start to flow around 650 apparently. So I'm wondering if doing it in the dark might allow me to control the heat input a touch better. I'm only using a basic B&Q blowtorch but those small sections heat up fast! Another factor might be how short that bit of steel spoke is. Any wind-up will be concentrated at the 'root' of the soldered join, whereas normally it would obviously have the whole length of the spoke to take up any twist. I was way over the tension I'll build the wheels though, and didn't use as high quality lube on the threads and under the spoke head as I normally do, so hoping it'll be ok. Perhaps I should do another and wind if back and forth to 'normal' spoke tension (about 100-120kg) a few times to see what happens. Oh, and... for weight weenies. A Sapim Race (2.0-1.8-2.0) is 5.8g, Sapim Laser (2.0-1.5-2.0, same base spoke as a CX Ray) is 4.4g. Makes weight savings of around 150g per bike over the Race spokes. Quote Link to comment Share on other sites More sharing options...
Ali C Posted November 11, 2021 Report Share Posted November 11, 2021 I feel like I'm gaining brain cells just by being near this thread, some impressive stuff indeed! Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 11, 2021 Report Share Posted November 11, 2021 Haha. Well, thanks... I don't think this is out of the realms of a regular DIY-er, just I tend to go a bit to far with these things. More nerding here (Berd's patent): https://pdfpiw.uspto.gov/.piw?PageNum=0&docid=10661598 - they do use cyanoacrylate to glue the spoke into the rim end. Scary. @Ali C, the patent only covers the USA and it would make an interesting video... just sayin'... 2 Quote Link to comment Share on other sites More sharing options...
isitafox Posted November 11, 2021 Report Share Posted November 11, 2021 Slightly off topic but have you still got the carbon fibre hub/s you made years back or did it/they die? (can't remember if you made just one or a pair!) Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 11, 2021 Report Share Posted November 11, 2021 I do! (Well, sort of, it's just a bag of bits now). It was just the rear one. I seem to remember either the bonding failed between the shell and flanges, or the carbon sleeve split - I think the 200mm rear disc I was using at the time didn't help things! 1 Quote Link to comment Share on other sites More sharing options...
forteh Posted November 11, 2021 Report Share Posted November 11, 2021 (edited) As daft as it sounds, a spot of cyanoacrylate might be enough on the spoke if you even need anything at all; the silversolder does give a lovely filleted finish once the flux is cleaned up though. Perhaps anneal and temper the stainless after soldering? The patent is quite an interesting read, I would hazard that they must have some sort of mechanical key for the CA to hold the spoke end in; could be a simple as a rolled thread, I guess it would key into the braid very freely. So how does the jig work? Must be some force to get the coil wrapped so tightly? edit: So they did look to use the finger trap to retain the spoke end but glued because you need less length (and associated weight). Edited November 11, 2021 by forteh Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 11, 2021 Report Share Posted November 11, 2021 Tempering could be possible, I need to read up on that... I did just test another soldered eye though and it was absolutely fine. I think the main problem was me being a butcher! I tried a straight spoke early days with a long rolled thread and no glue - it pulled out easily. I also tried gluing with the same rolled thread: CA pulled out (perhaps didn't get it soaked enough), epoxy 'skipped' on the rolled thread and then the rope started breaking at the end of the spoke - I'd even tapered it to reduce the stress riser. I am talking 200kg+ here though. One thing that might make enough difference, my rope is 2mm (though it measures at 2.2mm). The stuff Berd use is 1.5mm (have read that this measures up at 1.8mm), so perhaps the 'clamping' of the finger cuff trick is higher with the smaller rope. The jig... probably easier if I take a video, ha. It actually happens without any grunting somehow! You're not wrong about the nice finish of the silver solder. A lovely contrast to anodised aluminium and high tech rope. 1 Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 12, 2021 Report Share Posted November 12, 2021 More faffing... Decided I didn't like the twisted spoke in the end. Felt like it was a bit brutal on the spoke when forming the eye, and the thick to thin section felt wrong (stress riser). Had a mini failure at just over 200kg where the solder started to 'peel' away too. I hadn't prepped the spoke at all (normally I would sand it down with 120 grit and degrease with acetone) which is the likely culprit, but belt and braces... Ended up making a hybrid of the 'in line' eye from way back and the twisted one, which puts the silver solder more in shear than tension, and ensures the two lengths of spoke are touching for a good distance to allow proper soldering. Decided to go straight for a destruction test, so loaded the bugger up... BANG. Sapim spoke snapped at the first thread. This was at just under 150kg, so 300kg in the rope one. The rope held fine but the eye stretched a bit, necked down to 1.4mm from 1.8 at the very bottom. If any of these spokes see 150kg even momentarily during their life I'll be surprised, so that'll do me. Then went on the destruction testing warpath, and loaded one up to 115kg and attacked it with a file. The failure is actually quite boring, the strands just gradually detangle and the bury splice slips. At this point I'd put 20-25 firm strokes across the rope with a coarse round file, and it was still holding over 80kg. So I'm happy the odd rock strike won't cause issues! Need a new jig for the new eyelet type now... 7 Quote Link to comment Share on other sites More sharing options...
isitafox Posted November 21, 2021 Report Share Posted November 21, 2021 Been over a week now Ads, need an update! (this thread has become one of my highlights when I'm bored and want something to read!) Quote Link to comment Share on other sites More sharing options...
manuel Posted November 21, 2021 Report Share Posted November 21, 2021 It’s like waiting for another Binky video… Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted November 21, 2021 Report Share Posted November 21, 2021 Sorry guys, been busy with another part of the same project... but I have started on the spoke-making jig. Spoke progress will resume once the frame is finished, unless I get annoyed / bored with it in which case I'll come back to the spokes for a bit! Full build thread here: https://www.mtbr.com/threads/diy-steel-29er-singlespeed-frame-build-arse-29er.1196810/ 6 Quote Link to comment Share on other sites More sharing options...
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