This is also posted in Tea? but may be more of interest here.
I had a look around for some light weight stuff to build a light weight trailer to go with Tiddles.
I started with an old aluminium rucksack frame. The 'shelf' bit at the bottom was removed and put on the front side so that the concave surface becomes the trailer bed.
I then had a route around a load of old aluminium tent frames for some 'stuff'.
I cut the bent bits to make them shorter at the short end and so that they would interlock with a sleeve. One of the bent bits was flattened at the long end for later. The two long straight tubes are the axle tubes, one to fit inside the other. The smaller one was drilled to take the locating balls from the quick release spindles from the wheel chair wheels.
The flattened piece was then wrapped around one of the cross members of the rucksack frame and riveted in place to form one half of the central draw bar.
The other bent piece was then riveted into the short tube and holes drilled to take the turn screw and the snap release button.
This is the axle with the holes drilled. The smaller one was jammed into the larger one and a rivet fitted in the centre to locate it.
The front of the draw bar and the ends of the axle were then secured to the frame with stainless steel cable ties, pulled tight with the proper tool.
A quick assemble to check it all looks ok.
And dismantled.
I am now gluing some oak together to make the coupling for the Brompton seat post. It will be a wooden version of the aluminum one I fettled for a friend's Brompton. If it doesn't work I will make a proper aluminium one with a quick release airline fitting.
