Wooden bike - in miniature.

It is not a great thing of beauty, but this model has really helped my see where this is going. I cobbled it together in lunch break at work and then shot it on a green screen set down in one of the studios, on my phone. Perhaps I should have spent more time on it and shot it with a proper camera, but really at this stage that is not the point. I really wanted to see the shape of the frame in 3D. I tacked a print out of the bike design onto some foam core card and set about cutting it out. The foam core is not quite to scale, too thin for the main frame and too thick for the rear stays, but it is good enough to get the idea. Oh yes and I used square section brass for the forks...... Remember, cobbled together.

I made the forks too long on the model and it really makes a huge difference to the intended design. The bike now looks unbalanced, squat at the back and lanky at the front. I dont think it is worth changing the model at this stage. I like the model and I think I may make another, proper scale version at some time in the future. 

Bike design progress.

I was just looking at the Renovo site in more detail and noticed that they have the curved frame line around the rear wheel to shorten the rear stays as I have proposed I'm my last design. I am quite pleased as it means that I am doing something right in my bike design process.
There can't be many bike shapes that have not already been put out there, especially in the standard frame geometry that I am following.
Yesterday I thought it would be a good idea to make a model of my wooden bike design. Just made out of foam core and bits and pieces, it will be near as possible a scale representation of the design below. It's nearly done, I will post pics when it's ready.

Plywood.

Today I started swatting up on plywood for the frame components of my wooden bike. I am lucky that in Bristol there are a couple of very good suppliers, who stock a variety of hard wood ply in most thickness's. I have based my design around 25mm ply, so that is a given, what is not so cut and dry is the wood base of the ply. The one I have my eye on is a 100% mahogany ply. The only problem with that is the cost, £168 per 8x4 sheet. Too much for a test project, maybe if the proof of concept bike works I can make another with the expensive wood. So the question is, what else is out there. Well the main wood in cheap ply is spruce, a soft wood, which although lighter, I have ruled out because I don't think it will be strong enough in the high stress parts of the frame in the longer term. So that leaves other hard wood options. The one that seems best, affordable and made to high standards is birch ply. It is the most commonly available high quality ply, both my local suppliers carry graded birch ply from rough and full of knots to architectural grade.  Best of all, birch ply usually comes from sustainable forestry, something that is harder to to be sure of with the more exotic hard woods. The really good stuff is about £45 a 8x4 sheet, I think this is what I will go for.

The bottom bracket....

I had initially hoped that I could hide the bottom bracket mounting inside the wooden bike frame with a single metal tongue filleted between the two halfs of the plywood frame.  This may still be possible, but I am worried about the amount of torque that will have to go through this fixing, as it is one of the most mechanically stressed parts of the bike. My plan at the moment is to use a two metal mounts that sandwich the wooden frame. This will defiantly be stronger, but I also want to keep the metal work hidden as much as possible. If I can find a way of making this work then that would, of course be best. I had best get the sketch book out.

Design asthetics.

Making the first steps into bike design and frame geometry was interesting, but it produced a bike that was very conservative in its apearance. If there is one thing you can do when making your own bike, it is to personalise the design. As with any design proces it is all abut personal tase. I am not going to go really radical, I like simple, and I like curves, so I am going to try and work both of those into the shape of the bike frame. I also want to make the most of the plywood. I intend to shape the square edges back into curves, revealing the lamnated layers of the ply. I really like this look, it reminds me of map contors. In order to do this I have to make myself happy that the smaller components will still have enough strenght once shaped, as it could be taking a considerable volume of material away.

With the above in mind I had a go at reworking the first draft bike design. I relised that it would be a good idea to shorten he rear stays as mych as possible, so I curved what would be the seat tube to follow the line of the wheel. Now the rear stays will be the minimum length. They will probably need to be a wishbone shape to fix in well. i had thought about making the seat tube follow that curve but i want to have a propper ajustable seat within the frame so for the moment it is a chunky block there. I tried cutting a shape out there but it always looked odd, so I stuck with it being solid. I also started looking at where the bolts would need to go for the joins between the metal and wooden parts. Although not visible in this image, I have started designing the metal components, they will be embeded in the wood of the frame. Again I want to b sure that they will be strong enough. (notice the crank wheel is on the wrong side, this is just so I know where it will sit)
The most vital thing for me to keep an eye on at this stage is to design something that I am confident I can actually build. It is all to easy to get carried away. So far so good.

Bike design, next step.

I took the BikeCAD image below, with its acurate angles, (but designed with a steel frame in mind) and copied it in illiustrator. This llowed me to start plying with the proportions of my wooden bike design. It is amazing how fast little details acumilate and have a knoc on. For example, the only way to maintain the geomtry of the frame that I designed in BikeCAD, and add material for strenght, is to
increase it into the central frame viod. This in turn makes the botom bracket fixing point rather out on a limb, very low down. So that needed tweking and beefing up and so on. The above is by no means the answer, but it isthe first time I have seen what the shapes may actually have to look like. This will (I hope) evolve as I add detail and the inevitable probems arise.

Using Bike CAD

Having been all excited about materials and getting started, it dawned upon me to focus a little more on the actual design of the bicycle. Bicycle design can be just a few sketches on paper, like I did below, but I thought I would have a crack at Bike CAD an on-line bicycle design tool. It is set up with some basic templates for most bicycle styles that are then 100% customisable. So I went with a road frame and entered my hight and

chose some parameters, below is what came out. I have a geared bike and a fixed gear bike and I enjoy both for different reasons, but as you can see here I have gone for a single speed design, mainly because for my first complete build it will be easier.
Bike CAD is set up for steel framed bikes so I am looking at this for basic measurements and geometry. I found it really useful to be able to type in different seat post angles and see the changes to all the other angles straight away. No doubt this will evolve, but I like the basic simple shape of this bike and I hope it will be possible for me to adapt this into wood with out too many changes to the frame geometry.

Looking around.

Around the corner from where I work is a chandlers, so having walked past it many many times I decided to pop in today on the hunt for epoxy resin. It was a treasure trove of goodies, everything one could ever want for a boat, including a nice selection of epoxy resins. There are several good options for me, that are an all purpose laminating/ filling/ covering two part kits, in several sizes. I cant remember the brands but I will go back armed with pen and paper to study the options further.
I will use the epoxy resin to bond the two half's of the frame and to laminate any additional smaller parts. I may also use it as a covering coat, for durability, although that may well depend on how much I have left after the construction phase.

First bits arrive!

Those guys at Ceeway were quick. The first parts I ordered are with me already. They dont look like much but they are the main conecting components between the wood and the metal. They are, a mild steel blank bottom bracket and a long piece of mild steel head tube. There is enough head tube for several bikes.

The plan now is to buy some plywood from Avon Ply and shape up the main frame. From this I will be able to measure up the plates I need to weld to these new metal parts, for the best join. Both are high stress parts so getting the size and placement right crucial.

Insperation.

If my wooden bike turns out half as good as any of these amazing creations, I will be really very happy indeed.

Getting started.

I ordered the first parts today from Ceeway, a plain mild steel Bottom Bracket and a steel head tube. Their web site is a treasure trove of frame building goodies. Its enough to make me want to make a steel frame too, but that will have to wait.
Now that these two parts are ordered it feels like a real start.
I am planning to make the frame from ply wood, but keep the rest of the bike as standard, ie, mostly metal. So for that I need to make the places where the wood meets metal work well. I will make special shaped rear dropouts from mild steel, so that therear stays can bolt onto them. They will be longer than normal to allow a generous spacing of the bolts so as not to stress the wood  at the join. The Bottom Bracket will be fixed to the frame with a fin of mld steel welded at 90degrees to the BB and bolted into the frame. I will try and use the same principal on the head tube. I came up with this soulution as I didnt want to have to machine complex shapes around the metal parts. I think it should work out well. Fingers crosed, as it is at the heart of the plan.
I should note that the famegeometry is based on my 1980's Ralliegh frame on my fixed gear bike. i love the way it feels andrather than take a punt on a new frame design for my first attempt, I thought I would stick with what I know.

The plan.

This is the first effort putting what is in my head onto paper.

The idea is based on plywood. As I am not an engineer and have no way

of calculating the optimum strenghts of components I will be making my own guestimates

as I go along. The sketch below is drawn in square section, but I intend to round it off once the main shapes are put together.

 This is a first stab at a mostly to scale drawing.

Now I have to start looking for some good quality ply.

Why?

Ok so its a big question.
I have always loved bikes, of all types, motored or otherwise. I cycle to work and my children cycle to school. we are a cycling family. We have a van and a motorbike, oh and a morris minor too, but I like bikes. A while back i decided to try and restore an old Raliegh fram into a fixed geat comuting bike. I loved the restoration process and I love riding the bike even more, I still have it.
I have always enjoyed making things and one thing led to another and I decided to try and make a wooden bike. I have basic tools and limited build space, but I think it will only add to the challenge... in a positive way.
Wooden bikes can look lumpy and cubmersome, they can also look dashing and elegant. For the moment i will be happy if I can ride what I make. i think I will create a proof of concept 'attempt' first, and if that works it can be refined.

first post

Nothing to say really just testing this blog thingy out.