Bending a firehole tube

In message , virgin writes

First of all make an oval wooden male former to the size of the required fire-hole. Then...

Heat the copper to red heat and allow to cool. Introduce the copper to combined gentle ministrations of the former and a ball peen hammer. Initially the copper will be surprisingly soft but will soon work harden, so... Heat the copper to red heat and allow to cool. Introduce the copper to combined gentle ministrations of the former and a ball peen hammer. Initially the copper will be surprisingly soft but will soon work harden, so... Heat the copper to red heat and etc...

By now you should have a plain oval tube.

Now make an oval wooden female former with a 4" diameter curved end and round the edges. Trim the end of the copper tube against the former. The end of the tube now needs to be flanged outwards so that the flange will lie snugly against the outside of the barrel. So pull the tube through the former until sufficient protrudes to form into a flange. Then ...

Heat the copper to red heat and etc...

(Assuming it's to the GLR drawing and you've done the foundation ring and the holes in the barrels). I've kept the holes in the barrels for it circular. Turn up a piece of wood to 3.5" as a former. Anneal the tube. Gently and carefully form the tube by tapping with a hide mallet to the curvature of the former. Keep annealing, forming and trying the tube in its place between the barrels. It's fiddly and may need a some filing to fit but has worked OK on the ones I've made. Unless someone knows a better way! Stan Bray's articles from ME 1997 is useful. Any more help feel free

Kevin heyes

why not make the oval a little thicker (wider) and machine the boiler diameter into it.

Thanks for your help chaps,

I used a wooden former as suggested and it worked fine.