Barrel Elevation Gear

by John

This photo is the original Port Fairy cannon, and the 3D printed 1:10 model size copy. The original is ferrous and the guide is bronze or gunmetal. I decided to make my scale model versions from brass, for ease of construction, and to avoid rusting because these parts will not be painted.
I did not have a piece of brass big enough and thick enough to cut a 360º disk. It would have been 182mm diameter and 2.5mm thick. So, I made this fixture, and attached an aluminium plate.
Bolted on some bits of brass bar the correct thickness, using holes outside the gear, plus one which will be incorporated into the gear.
Then cut the teeth, using my CNC rotary table.
Then used the same fixture held in the milling vice, and cut the interior contour, and a rebate.
The ends still need to be shaped.
Showing the curved guides, rebates, and the bronze castings which secure the gears to the barrels

Making brass fittings is always a nice and enjoyable part of a modelling job. Making “bling” as my GSMEE friend John B characterises it.