Setting Elevating Gears on the Armstrong 80pd RML Model

The elevating gear is a quadrant gear, and it is centered on the trunnion centre. This is how I set it up on the model Armstrong RML 80 pounder. There are probably other better ways of achieving the result, but this is how I did it .

The barrel is removed from the carriage, and a round bar sits on the trunnion caps. The round bar is 20mm diameter, the same as the trunnions. The quadrant gear sits in position, and external calipers measure the distance from the quadrant gear to the exterior of the bar. The position of the quadrant gear is determined by its passage through the front transom. The rear position is determined with the calipers at the same setting.
The calipers measure the identical distance, at the front transom. The quadrant gear must be in the correct position. It is Super glued into position after marking.
Then the bracket which joins the quadrant gear to the cannon barrel is roughly positioned X,Y and Z. When satisfactory, the position is marked.
It all lines up. Next the BA8 fastening bolts will be drilled and tapped.

This is the second 80pd Armstrong RML model which I am finishing, this time for myself. It should be straight forward, having done it all before, but it is like a new adventure. Ah the joys of memory loss. Everything is new.