More Small Cannon Parts
I suspect that this post will not be of much interest.
But the parts represent 2 whole days in the workshop, so I am writing these notes for my own diarising more than your entertainment.
The chassis of the model Armstrong RML cannon has a cross bar, which is bolted to the longitudinal bar, and is attached to the side girders with some small, shaped clamps.
The cross bar doesn’t look much, but it has 4 bends and a twist. The space was too tight for me to measure the angles, so I bent the cold bar by estimating the degrees by eye. Same with the twist, except that the twist had to be confined to the section not attached to the girder or the central longitudinal bar. So I heated that to red heat with oxypropane. The twist was 4º. But I eye balled that too.
The clamps required some planning. I considered machining them from solid bar, but work-holding was going to be problematic.
So I silver soldered 2 strips together, cut off the pieces, then sanded, filed, and manually bent the angles.
p.s. Another day later, more of the same…
I would prefer to use 2mm metric bolts rather than 8BA, which is a similar diameter and pitch, but unfortunately I have been unable to find a supplier of 2mm bolts with hex heads. BA bolts are several times more expensive per piece than metric, and it adds up when using hundreds per cannon.