Take a look at the finished bicycle here..

Monday 11 April 2011

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.

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