.36 caliber Dalgren Light Boat Howitzer

[The Jeff]

At work I've been building up a box of scrap brass and last week the boss let me take it home. It's mostly 1/2" brass round bar about 3.5-4 inches long. There's also a few 5/8" pieces. As you can imagine, my mind was racing with possibilities.


I've never really done much with brass in a lathe so I thought I'd make a light Dahlgren boat howitzer because it's about as simple a cannon you can make. On Saturday I did a lot of research and drew up a set of plans. I got the dimensions for the barrel straight from Dahlgren's "Boat Armament of the US Navy" and I made the boat carriage from a picture. I measured the pixels on the picture, then calculated what the actual dimension would be. It ought to be pretty close. I did modify the chamber from the gomer style to a 1/3 cylindrical style when I built it though.

 
Next I started turning the barrel. I scaled my drawing down so the 8" breech diameter was .625" and the bore worked out to .36 caliber. Like I said, I've never done much with brass and it seems to be kind of splintery. At least I seemed to get more bits of brass stuck in my fingers than I usually get with steel. I drilled a hole through the wall, threaded it with a 1/4-28 tap and then screwed on a piece for the lug. Next I ran the 23/64" drill bit down the bore again and cut off the excess threads.



I shaped up the lug with a Dremel tool and a cutoff disk. It still needs a bit of work with a file. Then I started working on a boat carriage out of some hickory. I found surprisingly little on the internet about this carriage. Perhaps the best picture I found was from the CSS Teaser.



And this evening I started working on the lower part and cut the slot in it. After I finish the base up I'll make a brass A frame to hold the barrel and the wing nuts for the compressors.



I haven't drilled the vent yet, and I'm really not sure if I plan to. I don't know what kind of brass it is, but it did seem a bit brittle.

[BoomLover]

What you have done so far looks pretty good......

[GGaskill]

I am assuming that you haven't soldered the lug into the barrel.  If that is the case, I would be reluctant to fire it because those threads are an open invitation to the collection of fouling and would be difficult to clean unless you take the piece apart after each firing specifically to clean the threads.  Although it would force you to a smaller caliber, a steel liner would make me more confident about firing this.

[Soot]

I've considered making one of these barrels and attaching the lug using a dovetailed slot.
One of these days.

[jamesbeat]

I'll second that, being .36 caliber gives you plenty of room to fit a .177 liner.
That will negate the problem of the threaded section and your concerns about the brass being brittle.
It seems a shame to have such a nice piece and not fire it...

I'm not a machinist, but is it possible that the brass would be more pleasant to machine if it was annealed first?
Brass is really easy to anneal, just heat it to red and let it cool, or quench in water.
Too late for this one, but it might make all of those other pieces in your box easier to machine.