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  1. #1
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    A carbon / Kevlar DJ/Street/trial frame

    The latest project taking shape.


    Magura

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  3. #3
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    Quote Originally Posted by Drew Diller View Post
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    I hate to disappoint you, but this will be just another day at the office to you

    The only difference is the frame design, and the Kevlar armed tubes.

    Kevlar armed tubes might be something you'd gain something from looking into though.

    Magura

  4. #4
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    I just came to think of, that I have something as unusual (for me), as a drawing to show

    It at least gives an idea about what I am on about.

    Add to this a removable seat tower, like the old Intense DH bikes had it.

    Magura

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    Did you fab your own drop out or cut them from a pre fab'd sheet of carbon?

    -aron

  6. #6
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    Made of a sheet that I made a while ago.

    More to come the following days, as I am at a mates place working on it.


    Magura

  7. #7
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    What happened to the DH bike Mr Magura. I want to see the DH bike!

  8. #8
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    Quote Originally Posted by Fix the Spade View Post
    What happened to the DH bike Mr Magura. I want to see the DH bike!
    To be honest, I lost interest in it, so I gave it away to a friend of mine.
    The bike it was supposed to replace, has not moved an inch since last summer, so it seems a bit pointless to make another bike to collect dust.
    Last summer I built up a cheap and simple single speed DJ 24" bike, and since that bike saw the light of day, all the other bikes have seen little to no use.
    Hence this change of direction.

    The DH bike still needs a rear end, but the main triangle is done. I guess the guy I gave it to, will finish it during the winter.


    Magura

  9. #9
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    Here you got a pic of the current state of the project.

    Next step is prepping for stratification, and gluing in the last bits and pieces.


    Magura

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    Maybe it's time to tell about the aim and specs.

    I want to make this bike as versatile for my specific needs as possible.
    So, to be able to use it for street trial, the seat tower has to be removable, and the head tube angle must be like 70 degrees.
    For DJ there has to be a seat, so the tower goes on, but in the lowest position.
    For AM the head tube angle must be 66 degrees, and the seat can be moved up like an adjustable seat post, but the entire seat tower will be a parallelogram, with hydraulic height adjustment, and the seat angle will rise by itself, as the seat is lowered.
    The head tube angle will be possible to change within a few seconds.

    The specs:

    160mm rear
    370mm chain stays (I like that for some reason)
    BB 15mm above wheel center
    24" wheels
    Fork: RockShox Revelation dual air, lowered to 110mm.

    Aim to get the frame including hydraulic adjustable seat height, and saddle, down around 2700g.
    So far that seems within reach.

    Magura

  11. #11
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    Nice!! Keep it coming Magura.

  12. #12
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    This project is btw. also the first I will be able to get scanned for voids.
    A friend of mine has promised to do x-rays and a CT scan of the finished frame.
    Now that will at least make for some nice wall art for the workshop


    Magura

  13. #13
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    Ok, time for an update:

    The frame is pretty much finished by now, but I'm still lacking a bunch of the metal parts.
    Work seems to have gotten much in the way lately. Now I'm just dreaming of the days (like half a year ago), where I worked like 8 hours a week.

    Anyhow, I just got around to doing the mould for the seat tower, and will get the layup done tomorrow.
    It took a bit more calculations than expected, to get the seat height adjustment right, while maintaining a reasonable degree of suspension of the seat tower boom.
    I got myself a RS Monarch for that job, which now just need a few modifications, in order to work as height adjustment/suspension.

    A mould for a carbon/Kevlar saddle is also in the cards tomorrow, if things works out as planned.

    I'll try to get some pics of things tomorrow, before I put it all back on the shelf for the next couple of weeks.


    Magura

  14. #14
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    hmmmmm

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    No, YOU don't understand. You're making an ass of yourself for all of eternity.

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    Subscribed! Would love to see this one finished.

  17. #17
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    Ok, no update anyway, as yesterday turned into the biggest fail day.

    I experimented with a new type of breather, which I considered marginally different from the one I usually use.
    Well, not so. It compressed completely, and didn't let the vacuum through.
    The result was like 40% fiber content
    In other words, the result of this, was something for the bin.

    Back to square one, and no more experiments for now. This bike simply has to run before Christmas.


    Magura

  18. #18
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    Aww man. That's an f7u12 moment. I'm sorry to hear that.
    Disclaimer: I run Regular Cycles (as of 2016). As a profiteer of the bicycle industry, I am not to be taken very seriously.

  19. #19
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    Quote Originally Posted by Drew Diller View Post
    Aww man. That's an f7u12 moment. I'm sorry to hear that.
    Yeah, real stupid to make tests now.

    The good news is that it was after all just the seat tower boom.

    So like 100g of UD, 20g of braided sleeve, and like 200g of the most expensive epoxy I have.



    Note to self: make experiments on little pieces destined for testing, not stuff you plan on using.

    Magura

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    subbed.


    The way the seat-tube is diagonally cut looks like it could hurt in a bad crash. Mebbe should have laid the TT over it .....

    Just random thoughts - don't like my musings get to you.

    -S

  21. #21
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    Quote Originally Posted by shibiwan View Post
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    The way the seat-tube is diagonally cut looks like it could hurt in a bad crash. Mebbe should have laid the TT over it .....

    Just random thoughts - don't like my musings get to you.

    -S
    I did give that some thought, when I did the drawings (quite a bit actually).

    .....till I came to think of, that it's all hidden by the seat stays, and under the seat tower.
    All that would be a lot clearer to you, if it wasn't because I was too lazy to draw the seat tower

    Thanks for the heads up though, much appreciated.


    Magura

  22. #22
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    Bummer on the Breather not bleeding off excess resin. 40:60 resin content is a bit rich, pretty much like a chopper gun built boat, not good.

    I'm guessing the breather was a prepreg spec breather.

    OK, so now the big question, the Kevlar is obviously hybrid into the lay? Assuming you used 49 based Kevlar and not 29, plus hopefully it was not dyed unless an exterior decorative ply.

    You build some cool stuff.

    PK
    Reps! We don't need no stickin' reps!

  23. #23
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    Quote Originally Posted by PMK View Post
    Bummer on the Breather not bleeding off excess resin. 40:60 resin content is a bit rich, pretty much like a chopper gun built boat, not good.

    I'm guessing the breather was a prepreg spec breather.

    OK, so now the big question, the Kevlar is obviously hybrid into the lay? Assuming you used 49 based Kevlar and not 29, plus hopefully it was not dyed unless an exterior decorative ply.

    You build some cool stuff.

    PK
    Yes 40:60 is a far cry from the approx. 70:30 we usually get.

    Back to pressure and heat. To be honest I don't know why I all of a sudden found it smart to vacuum bag this, when the rest is made with pressure bladders.

    The breather was sold as wet layup type, but it looks different from the usual type, so it may be intended for prepreg. I didn't know there is a difference between the two.
    Fact is though, that roll of breather is no longer to be used for its intended purpose.

    Yes it's a K49. I have tried playing around with K29, but never managed to make it work with carbon. It seems to be too soft, and I either had to use a very flexible epoxy, ot the epoxy would crack if you looked at it wrong.

    By hybrid, do you mean weaved into the other layers, or just made in the same layup?


    Magura

  24. #24
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    Quote Originally Posted by Mr.Magura View Post
    Yes 40:60 is a far cry from the approx. 70:30 we usually get.

    Back to pressure and heat. To be honest I don't know why I all of a sudden found it smart to vacuum bag this, when the rest is made with pressure bladders.

    The breather was sold as wet layup type, but it looks different from the usual type, so it may be intended for prepreg. I didn't know there is a difference between the two.
    Fact is though, that roll of breather is no longer to be used for its intended purpose.

    Yes it's a K49. I have tried playing around with K29, but never managed to make it work with carbon. It seems to be too soft, and I either had to use a very flexible epoxy, ot the epoxy would crack if you looked at it wrong.

    By hybrid, do you mean weaved into the other layers, or just made in the same layup?


    Magura

    Technically there is not really a prepreg vs wet layup specific breather. It comes down to the prepreg starting life around a 55:50 resin content so much less is bled off and therefore the breather is not choked. They do offer some breathers that won't "crush" flat to low flow under the higher pressures attained in claves or non vacuum bag setups.

    As for hybrid, I was asking in regards to two materials in one ply. Hybrids can also be two materials in the same layup.

    As for your previous choice of K29, I can imagine it was not optimum in a structural type application. K49 is a structural type aramid and will layup easily. Why are you using the K49, protection or flexibility of the component?

    Send me a PM about what specific brand and weight plus other details about the breather. Maybe I have some laying around and can offer more experience details on using it.

    PK
    Reps! We don't need no stickin' reps!

  25. #25
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    Quote Originally Posted by PMK View Post
    Technically there is not really a prepreg vs wet layup specific breather. It comes down to the prepreg starting life around a 55:50 resin content so much less is bled off and therefore the breather is not choked. They do offer some breathers that won't "crush" flat to low flow under the higher pressures attained in claves or non vacuum bag setups.

    As for hybrid, I was asking in regards to two materials in one ply. Hybrids can also be two materials in the same layup.

    As for your previous choice of K29, I can imagine it was not optimum in a structural type application. K49 is a structural type aramid and will layup easily. Why are you using the K49, protection or flexibility of the component?

    Send me a PM about what specific brand and weight plus other details about the breather. Maybe I have some laying around and can offer more experience details on using it.

    PK
    So it's a hybrid but it is a layer of K49 on top of the carbon.
    It is part of something I did some testing on a while back.
    With K49 in the layup as the outer layer, and 0.3mm titanium sandwiched on with a 1mm neoprene layer afterwards, it seems to be virtually unbreakable.
    I did the tests on a square edge, which is my concern for the downtube in that place.

    I have not made any experiments with a 50-50 carbon/K49 layer. Would I get a better result with that for this application?

    I tried to find out what type the breather that failed is, but the company I bought it from claims it is the same as I usually get, which it obviously isn't.
    Sound like a good time to change supplier.

    You are most likely right, that the breather that failed, crushed under the pressure.
    I compared it to the breather I usually use. It can carry much more load, and seems to have a more open structure as well.
    Thanks for the offer to help though, much appreciated. You obviously have a load of experience in this field.


    The good news of today, is that I finally managed to make the titanium rear axle inserts.
    If there ever was a nasty piece of work, this would be it.
    It took like 3 hours to make them, as I lack power for machining that big diameter titanium. I only had 50mm diameter laying around that was big enough. It ended up with two inserts of 13g each, and a whole lot of Ti chips.


    Magura

  26. #26
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    So here they are.

    Magura

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    Quote Originally Posted by Mr.Magura View Post
    So here they are.

    Magura
    Nice... if only I had some titanium lying around like you do....

    I hate machining titanium... almost as much as inconel.

    -S

  28. #28
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    Quote Originally Posted by shibiwan View Post
    Nice... if only I had some titanium lying around like you do....
    I have a "market mirror stock".

    All the stuff that is easy to get, I have none of in stock.

    All the hard to come by materials, you name it, I got them all.

    Magura

  29. #29
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    Hey, it seems I broke the cycle of bad karma.

    The inserts for the head tube, were hidden inside a piece of aluminum I had laying around

    This officially makes this project ahead of schedule, as I have made the bearing mounts for the seat tower and the shock as well.

    Magura

    EDIT: that pic needed something for scale. They are for a 2" head tube.

  30. #30
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    nicely done carry on!!

  31. #31
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    I just machined the biggest rear through axle I have ever seen.
    14mm diameter, 185mm long!

    I still lack the fittings for it, so no pic yet.


    Magura

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    Here is the finished 14 x 180mm through axle.
    I made the titanium hex insert today, and glued it in.

    For scale is the 160mm Hadley hub it's made for.


    Magura

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    Sweet Stuff;

    I'd like to be able to do that, but I don't have the knowledge, I know, nor a capable machine, I don't think. Between me and Old Floppy, we make some pretty grody looking stuff.

    I noted when I blew it apart to polish that my new Salsa by Formula front hub had the adapter bushes on the ends to make it a 9mm QR, but had a pretty large bore on the actual axle. Makes me think about machining projects.

    Please continue for the vicarious machinists among us.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  34. #34
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    Quote Originally Posted by TrailMaker View Post
    Old Floppy
    Please name it something else
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  35. #35
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    Another awesome thread...Its nice to see stuff like this.

  36. #36
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    Quote Originally Posted by Drew Diller View Post
    Please name it something else
    Hmmm...

    A lathe by any other name, is yet still a tool, after all. It's really a question of end play.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  37. #37
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    The finished rear axle assembly.


    Magura

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    thats some purdy stuff i rekon so.

  39. #39
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    Quote Originally Posted by Mr.Magura View Post
    The finished rear axle assembly.


    Magura
    Darn it, Magura. Now you have me wanting to put discs and a rear derailleur on the kids' BMX. LOL.

    -S

  40. #40
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    Quote Originally Posted by shibiwan View Post
    Darn it, Magura. Now you have me wanting to put discs and a rear derailleur on the kids' BMX. LOL.

    -S
    With the skills you hold, and the toys you have, that ought to be a nice project, no?

    Care for a 40 hole blank?


    Magura

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    Quote Originally Posted by Mr.Magura View Post
    Here is the finished 14 x 180mm through axle.
    I made the titanium hex insert today, and glued it in.

    For scale is the 160mm Hadley hub it's made for.


    Magura
    I was just thinking about how to make a 20mm through axle and thought I couldn't without broaching an allen hole. Can you explain how you glued the insert in?

    Thanks, Joel
    NOTHING WORKS LIKE CLOCKWORK

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  42. #42
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    Quote Originally Posted by Clockwork Bikes View Post
    I was just thinking about how to make a 20mm through axle and thought I couldn't without broaching an allen hole. Can you explain how you glued the insert in?

    Thanks, Joel
    It's threaded and glued in, using Hysol 9466.


    Magura

    EDIT: After thinking it over, I don't think you can use this method for a through axle for the front, as you need considerable torque. In my application, it's just for a limited amount of counter torque.
    Broaching a hex in aluminum, is fairly easy to do. If you machine a hex and harden it, you can just press it through the aluminum. I do that a lot, though I usually grind a hardened rod to hex shape, but the principle is the same.
    Last edited by Mr.Magura; 12-16-2012 at 04:54 AM.

  43. #43
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    post 6 for photo. fun fun fun

  44. #44
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    Quote Originally Posted by Mr.Magura View Post
    Here you got a pic of the current state of the project.

    Next step is prepping for stratification, and gluing in the last bits and pieces.


    Magura
    Hey, is that an RC control propping up that frame? ....next to that battery pack?

    Didn't know you were into R/C.

    -S

  45. #45
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    Quote Originally Posted by shibiwan View Post
    Hey, is that an RC control propping up that frame? ....next to that battery pack?

    Didn't know you were into R/C.

    -S
    That pic is not from y place, so not my plane (plane peeking through the door), but besides that, you're right.
    I like RC Marblehead yachts though, and build such myself.
    Think composites


    Magura

  46. #46
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    This is going to be awesome

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    Quote Originally Posted by sasquatch rides a SS View Post
    This is going to be awesome
    I bloody well hope so

    This project is on the wrong side of 200 hrs. by now, and still in need of another 100 hrs. I guesstimate.


    Magura

  48. #48
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    Quote Originally Posted by Mr.Magura View Post
    I bloody well hope so

    This project is on the wrong side of 200 hrs. by now, and still in need of another 100 hrs. I guesstimate.


    Magura
    Wish I can trade my cooking skills for your skills, I'd be hungry but happy

    Good job Magura

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    Quote Originally Posted by Mr.Magura View Post
    I bloody well hope so

    This project is on the wrong side of 200 hrs. by now, and still in need of another 100 hrs. I guesstimate.


    Magura
    It's a hobby. A couple hundred or thousand hours doesn't matter.

    -S

  50. #50
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    Quote Originally Posted by shibiwan View Post
    It's a hobby. A couple hundred or thousand hours doesn't matter.

    -S
    Well, you know, I have other hobbies to tend to

    I did the math btw. for your suggestion to use PTFE for a plain bearing headset.
    I had actually guesstimated it to be far off, but it turns out that it's within the surface load limit.
    Thanks for the heads up. That's sure the next project to fit in this frame.

    Magura

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