Wooden bike
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Soooo heavy ?
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The frame members might need to be a bit larger in diameter than with metal tubes but I could see it working. The frame members will be laminated up from thin strips, right? Consider making the parts that have a left and right version--front fork legs and the frame work around the back wheel from strips that are a bit more than twice as wide as the individual parts. Then split the pieces out with the bandsaw.
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I think the plan was to use ash for the members (im not very familiar with it, so any suggestions for better materials are greatly received.)
Making left and right versions sounds sensible though. and i dont think we were going to bother with doing forks, so shouldnt need to worry about that.
heres a quick mockup of the original idea, this would be the top of the seat tube:
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Ash is a strong wood and it would be a good choice. Hickory would be good too if you can get it. Woods that are commonly used for things like shovel handles
As I mentioned, laminate thin pieces to make thicker ones and glue them clamped to blocks to create the curves. If the frame members are to be straight, you could rive them out of larger stock like they make proper ladder rungs. You need to avoid having the grain run out the sides or you;ll end up with weak spots.
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I don't know if you'll want to try this, but I have seen a gunstock mfg'r that laminates to pieces of walnut together with a piece of carbon fiber cloth in the lamination. If you were to use the thin strip lamination idea, placing a piece of carbon fiber cloth in the lamination should add strength to the laminate. There would be a black line in the lamination, but that might contrast nicely with either ash or hickory. I guess you'd also have to pay attention to the direction forces were applied in relation to the orientation of the fiber.
Just a thought.
GT
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I think that idea would be very cool, chemtech. It wouldn't be that difficult to do either. You just need some good shears for cutting the cloth.
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That sounds like a pretty cool idea, i'll suggest it to my friend.
He's pretty keen on carbon fibre (he's a bike freak) so he'll lap it up
Just an afterthought, doesnt carbon fibre gain its strength form being laminated in several layers and having a resin applied? i.e. would just whacking a piece of cf cloth in between the 2 laminates actually have any advantage? or would you need to get the resin out?
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You'll need to make more than two layers of laminations. Figure more like 6 or 8 depending on the diameter of the frame pieces and the length. I'd put a layer of carbon fiber cloth between all of the layers of wood. Use epoxy for the layup and make sure each layer of cloth gets well wetted out.
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Cheers for the clarification.
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Remus,
The idea (wood plus carbonfiber) isn't new.
Take a look at http://www.jangunneweg.nl (both English and Dutch). -
Hi Remus, hi folks.
May be your frined can use thick plywood and cut a large opening so the frame will be what would be left and be only one piece.
Another possibilitie could be to use broomball sticks or hockey sticks. These are quite solid.
Just ideas.
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Not sure about the plywood idea jean, it would be pretty wasteful and not very stiff either. Could be quite wasetful as well. Also not sure how youd go about doing the rear triangles.
the hockey sticks sound like an idea worth investigating though.
Saying that, my friend has currently put the project on hold because it's "too specialist" or some other nonsense. I told hed be a fool not to do it but he wasnt convinced.
Im thinking about giving it a go at the end of the year, though, i'l just have to see if i get any spare time.
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Actually plywood could work. Yes, it would be wasteful, though. Layers of marine grade ply could be glued up with a wedge shaped spacer to split out the rear. You could do all kinds of funky things with the frame shape.
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A bunch of links to flesh out the topic.
cnc wood
http://bikeportland.org/2008/02/07/nahbs-preview-introducing-renovo-hardwood-bicycles/#more-6633
http://www.xylonbikes.com/models.htmlruminations
http://bicycledesign.blogspot.com/2008/02/bent-ply-bike-sketches.html
http://bicycledesign.blogspot.com/2008/02/more-wooden-bikes.htmlbamboo
http://cozybeehive.blogspot.com/2008/02/bamboo-natures-composite-part-1.html
http://cozybeehive.blogspot.com/2008/02/bamboo-for-bicycles-part-3.htmlpushing the envelope with wood... a wooden supercar
http://www.joeharmondesign.com/
http://joeharmon.blogspot.com/ -
cheers for the links.
Whenever i see that wooden super car i always marvel at how easy all my projects seem in comparison
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I know a bit about bicycles and a bit about wood. I think you can build an interesting bicycle out of wood, but I don't think wood is really a good material for the application.
The three main tubes on a bike could be made of wood with little difficulty so long as the joints were still made from steel. But it would not last long because you can't bond wood to steel without making allowances for wood movement and any such allowances would require a loose joint.
As you look at a bike, you will find that there is really very little tolerance for material. For example, take a careful look at how the area around the bottom bracket keeping in mind the space taken by the tire, wheel, chain (in various gears), crankset, and chainstays.
Some decent bicycles have been made with bamboo, and I've read about efforts to do precision work in hardwood, but I suspect that they are basically carbon fiber bicycles with a bamboo/wood substrate. If they are taken care of well and the wood is completely isolated from moisture, they will probably be nice, but heavy bikes.
Bicycling puts surprising stresses on the frame and some components and the tolerance for failure is low.
All that said, I can imagine a market for high end "comfort" bikes made of wood, or with wooden accessories. I've also looked at what would be involved in making wood rims. Wood was the original material back at the turn of the last century, and for a tubular tire it's not terribly difficult.
Good luck - be careful - prove me wrong.
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One of the guys in my shop did this with one of our cutoffs and something he found in a dumpster...
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A true lightweight masterpiece!
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To really add strength, the carbon fiber needs to go on the outside of the member.
I love the idea of bent laminations. You could do much of the jointery that way, if you think about how you'd like it to look and to be strong. Then making it is just problem solving— one by one and you are done.
How do you plan to adjust seat height?
When I think of the strength of a shovel handle vs. the strength of a bike frame (thanks for the example), I think the shovel handle would win hands down. It will be heavy, though, and that will be an issue if you do much riding.
Best Luck,
JIm
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@jim57 said:
When I think of the strength of a shovel handle vs. the strength of a bike frame (thanks for the example), I think the shovel handle would win hands down. It will be heavy, though, and that will be an issue if you do much riding.
If anybody's still playing with the idea, I'd suggest solid bois d'arc. It makes ash look like balsa by comparison, though you need it completely cured out first, and it will blunt any tools used on it. (I used to turn it on a lathe with HSS tooling, and it was a constant two-passes-and-touch-up-the-edge process.) Once properly cured and finished, it's incredibly resilient, and as it ages, it tends to get even prettier.
I watched a friend ruin a decent axe trying to cut a 4" limb, and I've bounced a 10lb maul off a log 8-9 times before making anything that could be considered the start of a split.
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