Hello
I am just getting some ideas on a cannon build.I have a guy at a foundry that will pour a cannon barrel for me. But I am quickly learning that it not just that easy. The barrel would be about 24" long 4" at largest diameter. So my questions to the fine folks of this forum are
First welcome to our forum Chris, always glad to have a new face join us.
You are on the right track coming here. You are asking questions before you start building. All to many guys come here after they bought some unknown cannon off the internet or have built a gun, and then start asking questions.
The first thing they are told, is their gun is not built to proper safety standards or just plain doesn't look right.
First let me say something about oddball, doesn't look a right cannons. I am very critical of such guns. I am that way for a reason. The way a gun looks convey a message about its maker and shooter. If a builder has no idea what a cannon should look like, that tells me he probably doesn't know how build one safely either. There is no comfort in a statement by a cannon maker who says, I have sold hundreds of these without a problem. Almost every cannon accident we see reported, someone says, "we have shot this for years without a problem!" That is an "oh duh" response.
When I see someone shooting one of these amateurish looking built cannons, the first thought that goes through my mind is, if this guy doesn't know what a cannon should look like, then he sure doesn't know how one should be built safely and probably doesn't know how to shoot one safely either.
If you will go to the stickies at the top of this board you will find a post called safe loads and construction. Read it. Read the links in it. That will give you the minimum safety standards for a building a cannon. These same safety standards apply to casting cannons.
The first thing you need to do is find your self a cannon design and copy it. You can get cannon plans from Antique ordnance publishers. A link can be found in the cannon links sticky under cannon plans. A good inexpensive book to buy showing cannon designs is Round shot and Rammers. You can find copies on the used book market at
www.abebooks.com.
If you use an existing plan you can scale dimensions to meet your needs. The only dimension you may need to adjust will be the bore dimension. You need to have the wall over the chamber the same thickness or more as the bore diameter. You will hear this referred to as the one caliber thickness rule. If you use existing plans you will end up with a more pleasing appearing cannon, that you can display with pride, that doesn't appear to have been made by Bubba Leroy's Shade Tree Cannon works and is safe to shoot.
1 can this be poured in iron, if so does it need to be lined? how is that done?
2 if it can be poured from bronze is that better, does that need to be lined?
The best and safest way to do this is to cast with mould standing muzzle up and with a large sprue puddle and cast the cannon solid.. Do not cast around a liner. For steel the temperature of the molten metal can and will melt the liner and distort it or dislodge it. Cast the cannon solid, machine the bore out and then insert the liner. Construct the liner as out lined in the Construction sticky.
3 I was thinking a bore of 1.72, what do i need for a powder chamber if any?
There is no need for a reduced chamber if you simply follow the one caliber wall thickness rule. People will try to build a cannon with a too large bore on a piece of steel that is too small for the bore. In order to compensate they have too build a smaller chamber than the bore. It is not needed for a properly planned new build.
The reduced chamber is found on smaller lighter howitzer type orignal guns and requires some advance skills to load. Plan your first build to avoid the need for a a chamber.
4 what is the smallest the barrel wall can be at the muzzle?
As mentioned above if you use existing plans and scale them to your needs and adhere to the one caliber rule, you do not need to be concerned about this problem. The original designs compensated for the issue.
Thanks in advance for any help you can give me.
Chris
You are most welcomed, it is a pleasure to share. That is how most of us learned, from the sharing of others.
