Have a look at the original Plycycle here .

4 August 2014

Metal work takes a step forward.

Even though this is a wooden bicycle frame project, certain parts do need to be made from metal.
The head tube fixing and bottom bracket are areas of huge stress so these need re enforcing within the wooden frame.
I have worked with the same design I came up with on the first PLYCYCLE. It uses metal plate brazed onto or around the main component that is the sandwiched between the wooden layers with epoxy and then bolted for good measure.

Bare bottom bracket beside scale drawing of stress plate.

Once the parts were made up I asked my pal Lew Gardiner to braze them together. Which as before he did. This time his welds were not very tidy but strong none the less. This is a major step as I could now get onto fitting the bottom bracket into the frame.

Head tube and bottom bracket with stress plates brazed on. Deep score marks added for gripping to epoxy.

The fitting was fairly straight forward. Just a case of routing out an equal cavity on either side of the frame for the plate to sit into, plus any additional excavation for bulges in the brazing.

Frame routed out to fit plate.

Plate fitting nicely.

I'm glad to say that the bottom bracket fits well, see below. Next I have to fit the head tube.

Frame fitting over bottom bracket and plate. Side view.

Frame fitting over bottom bracket and plate. Front view.