An internet search lead me to diagrams of naval guns from the Continental ship Philadelphia, with dimensions. Using some math-fu, I printed two versions of the diagrams; one at 1:48 and the other at 1:56 scale, to cover the ends of the 25mm gamut. (The guns pictured here are also a larger bore than the barrels I acquired). I laid the brass barrel onto my printout to see what size carriage would work for it, and went with the smallest carriage of the 1:56 set.
The appropriate sized carriage was cut out and traced onto heavy paper stock to use as a template to transfer the outline onto 1/16 in basswood. I then cut out the pieces with a dull exacto. After they disintegrated during cutting, I repeated the process with a sharp exacto, with much better results.
|Basswood and dull blades do not mix.|
Since the gun barrels came sans trunnion, with only a simple hold drilled where they would be, I mounted them on 1/32 in brass rod, clipped to the width of the carriage.
Using square needle file, I cleaned up my cuts on the stepped tops of the carriage. Then a test fit to check proportions of gun vs. mount.
For wheels, first I searched my wife's sewing box for tiny buttons I could use, but her collection of odd buttons was just that, and i couldn't find four that matched. Instead I found a dowel of the right diameter, and cut "pennies" off the end.
Rather than mortise the wheels onto tiny axels, I changed my mind and opted to create a sturdier model, since the wheels were cut against the grain. These axel nubs were cut off and sanded smooth and the wheels glued to the four corners.
My naval officer decided to inspect the first of his guns.
The scale seems to check out...