Finally I have a curved smokebox door for the miniature Burrell traction engine.
The radius turning tool has taken a few days to devise and make. However, I managed to set this at 71.4mm radius and turn the dome on the smokebox door.
I must admit that turning mild steel in this way is not easy. However, lots have told me that this turning tool is dangerous and will not work. The proof is in the results.
39.2mm diameter and with a rim thickness of 1.5mm this is quite a small door.
OK, after turning the dome I hand to use emery and then wet and dry paper to get a reasonable finish.
The radius tool is not quite stiff enough and so you do have to set the tool up precisely. Even then, mild steel is quite an ask. In brass the results are much better.
Now I have a curved smokebox door I needed to dome the brass nameplates.
I annealed the brass in a flame and then once cool I clamped the parts onto the domed door using a piece of rubber and wood to give some compliance.
Note: in order to hold the parts in place I tacked them to the door using a small amount of superglue.
It’s quite easy to remove the superglue if necessary by heating the parts up.
That little bit of curvature makes a big difference.