The fix?

      I have had a good look for some replacement forks second hand, and there are some nice ones out there but I cant use them because I have made the head tube on the plycycle longer than average. All the second hand forks are cut down. I don't want to 'fork out' for a new set, so I am going to work with what i have.

How did the front get so out? Well... The head tube is longer (for strength binding to the wood) and therefore lifts the front of the frame, and the forks are slightly longer (off the shelf and cheap) and although individually these extras don't seem like much in the end it is about 3.5cm of lift. Enough to radically move the front of the bike away from what I had in mind.

I put the photo of the bike into photoshop and measured and analysed and this is what I think.
with the forks I have I will never get the top of the frame horizontal with the ground, I can handle that, just. As for the relationship of the front wheel to the main frame, I can play with that a bit. Luckily there is plenty of room to adjust the angle and position of the head tube mounting. So I propose moving the head tube back and steepening the angle. This will take the top of the frame further from the horizontal but I think will bring the bikes proportions back together.

Looking at the angle change in photoshop.

Hopefully I can make the tweak easily enough, and then it really is put it together time.

Head tube.

While trying to move things on I thought I would have a go at assembling the front end of the bike. Stating with the head tube I proudly got out the head set, lined up the pieces and offered the top bearing cup up to the head tube. It didn't fit. Not just in a small way, there was just no way it was ever going in. For those of you who are reading this having made your own frame from scratch, you will now be realising how green I am to this.
I was worried that I had bought the wrong size tube or head set or both. On double checking, I had the correct ones.
I decided to swallow my pride and put in a call to the guys at Ceeway where I had bought the tubing from. They were very patient with me and explained all about reaming.
Reaming. The tubing is sold with an internal diameter that is slightly too small for the headsets. This is because as the frame is braised, distortions occur and the tubing is often not as truly round as it should be. So when the braising is complete, the frame is 'reamed and faced' to true it up and cut it out to the correct size for the head set.
So my head tube needed reaming. The tools I needed were easy to find but very expensive, so a quick web search brought up Argos racing cycles, bespoke frame builders and restorers, who are fairly local to me. I nipped over one lunch and they were more than happy to do the job for me for a fraction of the cost of the tools. Perfect. I pick it up next week.

Frame tacked together for dropout measuring.

In addition to the front end shenanigans, Lew and I have been mithering about with the drop outs. The actual drop outs have been bent to match the angles of the stays. Lew bent the stainless drop out sections with an oxyacetylene torch. The next step is to make the tube fittings to fit the wood. As mentioned below, we have revised the plans for this a couple of times, and we think we have now got a simple and effective way forward. The only recent change in plan is in how to physically join the drop out plate to the tubing. Normally a simple butt would be used and braised together. However because of the over sized tubing I need to accommodate the wooden stays, a butt was not going to work as well as we thought. It would need an insert made, and that is just too much machining for this project. so we have decided to try and squeeze the ends of the tubing into an ellipse using a jig, to take the shape of the drop out and make the braising more straight forward. Lew is testing this weekend, I will reveal the out come soon.

As you can see above I have put the frame together slightly more formally in order to get the drop out angle was right. I found that by the bottom bracket I needed a wedge, as my initial measurements had been wrong. Nothing a bit of resin and a bolt cant mend.

It was also an opportunity to start putting some of the bolts into the frame. The first being the bottom bracket ones. These now go thought the metal fin inside the frame and it is rock solid. When the frame has its final lamination (when the head tube is done) It will re-enforce it again.

I also need to start thinking for a name and a badge to put on the front.

Fitting the metal work.

I really felt like I have made a step forward with the coming together of the metal parts and the main wooden bike frame. So what did I do? Well.... I split the frame into its two halfs and inserted the metal pieces to daw around them.

Bottom bracket lined up for marking.



I then routed out inside the markings to allow the plate sections to neatly sit between the two halfs of the frame. I also cut some slightly deepersections in the center of each plate to allow some extra epoxy to create a plug. The plate will have some holes drilled in it eventually to allow the epoxy to bond though.

Botton bracket fitted.

Head tube fitted.

At the mement the pieces are fairly loose fitting because of my relative inexperience in this type of building. I think that the epoxy resin will help me out here.

The next few steps are fiddly and there will be no aparent progress, as in new parts. Its just bonding, and tweaking to get the rear stays to fit. Rear drop out parts are in the post, and will heavily influence how the back end of the bike turns out.

Metal work, works!

   I have in my grubby hands two pieces of metal work greatness. Lew ( the engineering man) made the parts up for me from my card board templates. I had stock head tube section and a standard blank bottom bracket shell from Ceeway, which I bought back at the start of the wooden bike build in order to measure up to. As the wooden frame came together and I understood more clearly where and how the metal parts would need to fit, I was able to discuss the detail with Lew. He then made a jig to hold the plate at 90 deg' to the tube as he braised them together.

Head tube and fin fixing.

    Hopefully this shows how I intend to sandwich the fin between the yet to be laminated wooden layers that make up the wooden bike frame. The Head tube has a wedge shape to it in an effort to increase its holding strength in the frame, it may well be bolted through as a precaution too.

Bottom bracket with fitting fin.

      With the bottom bracket, we decided to take the fin all the way around the shell. Originally I had intended to have the bottom section of the bracket shell exposed with the fin similar to the head tube. But then I decided to surround the shell with wood, and after discussion with a couple of engineering types it seemed a good idea to get as much strength into the bottom bracket area as possible. It seems obvious, but the stresses going through this section are huge, especially if I go fixed gear or single speed with the bike. Gearing it will drasticly reduce the loading, but I don't really want that.

   Next I need to paint the bits that will be exposed to the outside, while leaving the bits bare that will have direct epoxy resin contact.

   I have also just ordered  from Ceeway, two blank stainless track style drop outs and some 22mm tube to make the rear stay/drop our connections. I had hoped to use the left over head tube but it was just too big at 31mm diameter. Ceeway is just a treasure trove of frame building bits.

   On the wood working front, I hope to have the stays shaped soon and if the weather is warm enough I will have a go at the first stage of bonding the four frame layers into two halfs.

Frame template.

So with a big sheet of ply staring at me I wanted to jump right in and start sawing. However, being on a tight budget, I decided to take the advice of Micheal and Jeff, and start making a card board template. So I made one, and laid it up on my 1981 Ralliegh fixie (which I love the frame geometry of ) to see how it worked.

Not too bad was the answer, but there were some tweaks to be made, so I drew out and cut another.

Its laid out a bit squiffy here in the pic but it does actually fit cleanly. The thich section infront of the rear wheel is the biggest change, and I like the first template, but for strenght i will go this way first and can cut the section out later if it looks like the strenght is there. You can also see that i laid in a couple of scraps of ply to see what the rear stays might look like.

  
I am worried that they will not be strong enough, even with the main frame hugging the wheel line. So I am looking at extending the rear drop out frame to go furthur up the stay and hope fully reienforce the stay.

It may look something like this. I did some snap tests with a lenght of the new ply wood the correct lenght and width for the stay. On its own it beaks with relativly little force, doubled up (one for each side) the strengh is obviously double but felt much better to me. Add to this the strength of a triangle shape when bolted into position with a wheel and the drop out extention ( to reduce the leverage) and a two part epoxy resin top coat and I think it will be ok. Only one way to find out.

Other bits to arive last week were the crank set and bottom braket, thanks to Charlie the bike monger, great for bits n pieces. so with most of the hard wear now on the bench, I can relly start measuring up.

I've got wood.... plywood.

So I finally made it to the wood shop to investgate ply wood for my bike. Robbins timber, in south bristol are set up to supply the boat building and mending trade, so have a very good stock of hard wood and marine ply. I was only going to have a look, but one thing led to another and I came home with a half sheet of building grade 25mm hard wood ply. It is less than half the price of marine grade which has no air gaps between laminate layers, this does have strctural / strenght implications, but for my prototype I will be fine using this for the frame, rear stay, well i am not so sure.

The lovely lovely timber yard.

My new piece of 25mm hardwood ply in the van.

More bits.

Ah ha ha haaa, a couple more bits arrived in the post. I have gone for a 1 inch head tube and fork set up. I had already bought the head tube section of tube ready for cutting down to size, so I needed to get a set of forks. I have to make this bike as economically as I can, so I have not gone for super light or posh branded components so far. I am not anticipating this bike to be light weight, but I hope it wont be cumbersomely heavy either. Anyway, I found a set of forks that will fit nicely and look nice. Being fairly cheap they are slightly chunky, but I think this will help with the inevitably slightly more chunky look the wood will have. Also a great thing about this set of forks is that the threaded section is over long and can be cut to size. Many of the budget forks have a pre determined thread length.

I bought the stem from Velo Solo a great web site supplying specialist parts for fixed gear bikes. It is a reforge of a very popular old Cinelli stem. I already have one on my classic 1980's Ralleigh fixie, it is a stylish looking stem, but best of all doesn't break the bank. I also have a new head set in the garage left over from my fixie conversion, I didn't use it as I chose to restore the original instead of going new.

So the bits and bobs are gathering, I want to get some wood next to do some testing.

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. 

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.