Hand built bespoke bicycle frames in the heart of the Wiltshire countryside - dmoframeworks@gmail.com.
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Saturday, 22 September 2012

The first two dots have been joined......

As described in my last post, the next step was to start joining all of the various "hardpoints" of the frame together with the tubing.

I still need to finalise the seat-tube, as such this one wasn't an option to shape, so instead I started work on the downtube, see pic below:

Downtube Done

Mitre to headtube - this one took 53 minutes, next time I think I'll do the hard mitre first and then the easy one.

Mitre to bottom bracket shell - the easy one!
One thing that sprang to mind while shaping the downtube is that before I braze it in place I will measure the length and maybe trace the mitres so that it will take me a fraction of the time to shape this tube on frame number two.

This did make me think that, should I wish to start making frames more regularly, some kind of automatic mitre-ing device would come in very handy indeed!

Next up I need to finalise the seatube and get hold of it so I can cut in the top tube.

Frame Jig Complete

A late night last Friday combined wiht a very late night last night has resulted in the frame jig being completed - see picture below.

Here we have (from the bottom clockwise) the seat-tube locator, the bottom bracket shell mount, the headtube mount and the drop-out mount.

Close up view of the drop-out mount.

Close up view of the headtube tooling.
Next up was to accurately mount this lot onto the jig back-board. In order to do this I printed out a 1:1 scale plot of the frame and the tooling.

I set the centre of the bottom bracket and this formed the datum for the location of all of the other aspects of the frame.

Next was to set the sliding drop-outs to horiontal and the rest was easy!

Marking Out
Mounted Tooling
Next up is to start joining the dots!!!

Thursday, 6 September 2012

Frame Stay Tooling & The First Bent Stay!!

The next step in the build has been for a while to pluck up the courage to start practicing with bending the tubing for the seat and chain stays.

This has been for me the most intimidating part of the build as it was the part I knew the least about and the lack of information on the Internet regarding techniques other people have successfully employed only served to make this task event more daunting.

I did find one picture of a stay bending setup on the net which was comprised of a set of form tools mounted in a fly press. This seemed pretty simple and after a quick chat with Piet (now my full time wood turner and general jig building consultant!!) we decided on a plan to make a set of tooling.

The picture below shows the turned piece of wood which will be used to form the basis of the bends in the tubing, for initial tests this will be mounted in a vice and the tube pulled around it to form the bends,

Turned Wooden Form Tool & Bar Clamp
Because I was so keen to test the tooling and also wanted to see if I could get away without needing a fly press I modified the turned block to incorporate a clamp to hold the tube during bending.

The next step was to have a play with bending a tube.

Tube Being Bent
This technique definitely requires some honing however the results of the first bent tube were pretty encouraging.

Chainstay Number One!!
At the moment these test pieces are being done using cheapo seam welded tube of the correct diameter. I need to do a couple more tests to accurately determine how far the centre of a bend ends up being from the mount in the form tool and I should be good to go on the real things!!

Next up should be a finished set of stays and even maybe all the bits on the jig ready for some brazing action!!