Half Gun Drill Jig directions:

Half Gun Drill Jig.
I have made this Jig to control the size and location of the hole(s), for pressing the half guns into the parts,
(in my case, # 31 (5 by 15 MM) for the Victory by Corel)
that were cemented and pinned in place between the bulkheads, prior to the planking of the hull.

The plans show the location of these parts to some extent, but not definitively enough for me. So, I cemented two pieces of 5 by 15 MM together, the result being 10 by 15 MM,
and fit them in place between the bulkheads as required.

That gave the hull more strength, and me a margin of safety, in regard to the protrusion of the half guns, that I would have to control after the planking. This Jig works in conjunction with the Gun Port Sizing Gauges.

I used a piece of Nylon I had, but the Jig can be made of almost any material,
the important feature being the drill bushing pressed into it to guide the drill.

I also had a standard drill bushing that is used in commercial jigs and fixtures.
You can buy them, or you can make them. They can be made out of any material
that will withstand the forces involved when drilling the holes. Such as steel, brass, aluminum,etc.

We are not talking high production here.

The dimensions are:

A piece of Nylon 3/8" thick by 3/4" by 3/4" square.(.750")
A step was milled into it 1/8" (.125") deep all around to form a smaller square, that should be a snug fit for your gun port openings ( in my case, 10 MM .394" ). Then, in the same set-up, to insure centrality, the hole for the bushing was bored.

This must be a press fit. My bushing was #49 (.073") inside diameter, 13/32" (.203" ) outside diameter.
by 1/2" long.

The assembled Jig is then put into a gunport opening, and the hole drilled, keeping pressure on the Jig to prevent it from dislodging. For those who do not have a milling machine, the Jig can be made from two pieces , cut on a saw, and cemented together