For the non engineers, this job could be a little tricky!
I need to bend two Aluminium tubes to form the rear cable guides
First requirement is a former, cut to the required arc size
Aluminium "age hardens" with time and is stiff and inflexible and needs to be annealed…..This is done on the kitchen stove or a blow lamp.
Heat the tube for some time, all over and cool off under the tap
Clamp the former securely to a flat surface and gently bend the tube over the former……..Be careful!…..The tube is now very soft. After several minutes of bending and shapeing…..The Ali…….."work hardens" and needs to be annealed once more

The former……Use the table surface to keep the bend flat

There we go!…..The jobs done
Filing the ends accurately was quite fiddly
Bob