A Peek Inside Nick's Workshop

 

One reason the GNAT has taken a long time to become available is that a lot of equipment is used in its manufacture. This page looks at some of the processes involved in making just one of the dozen or so brazed steel parts that are supplied in the kit:- the seat back.

Three tubes are bent from 1/2" diameter Reynolds 531. A specially-made machine does the job nicely. The shot on the left shows the longest tube ready to be cut off. Presets (right) produce consistent bends requiring a minimum of fitting to the jig.

 

The seat back has three steel bushes, threaded 8x1.25mm. Some day (soon, I hope), I'll find someone with an automatic lathe to make them for me. Until then, making a seat back needs 12mm steel rod to be cut into short lengths (left). These pieces are then drilled, threaded and faced on my lathe using a cobbled-together 4-way tool turret (right). Note my touring bike in the background.

 

Three pieces of 3/16" dia. wire need to be bent. Two of these are the loops at the top of the seat which enable a pannier, lights, or a fairing to be attached to the trike; the third reinforces the bottom. The wire is formed on a purpose-made tool (left), and cut to length (right) on a bench shear. (photo obviously taken in winter!)

 

The ends of the tubes may still need a little bit of filing, and everything needs to be cleaned and fluxed before assembly. The shot on the right shows the seat-back in its jig ready to be bronze welded. This joining technique, the traditional way of making cycle frames, requires an oxy-acetylene flame, and produces very strong joints with thin-walled tubing.

 

When the seat has been brazed in the jig, it is removed and the parts of the joints which were inaccessible are finished. After a little bit of cleaning up it leaves the workshop unpainted; the design (right) turned into reality