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Discussion Starter · #1 ·
Im talking to a builder about a 3 inch bore one.
Hes going to use 1026 cold drawn seamless tubes, one on top of the other.
3/8 inch square threads.
My question or concern is the chamber metal.
1.5 inch metal around chamber and 2 inch behind it on cap.

I kinda thought we wanted close to one bore thickness, he said this is safe.

Thoughts?
 

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This is why they use internal breech screws in more modern cannon . The external screw cap on the Whitworth might be safe if used to spec's but it has nowhere near the safety factor that a internal breech screw has. With only 1.5 in walls things have to work right all the time to be safe .
 

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Discussion Starter · #7 ·
I dont know about plans other than it will be similar to an original.
I had been looking for something around 3 inches so i asked about that size. I also said i could do smaller if needed for safety. Builder said 3 can be done safely. Just wanted the consensus here about type of steel and chamber area thickness.
Granted im not giving you much info, i dont really have it, just basic guidelines.
Does it sound safe?
 

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I do not like to be discouraging, but some time it just cannot be helped.

I think you are going about this entire project wrong. I think you need to do a whole lot more research before you begin.

You say you want to build a Whitworth. Good project!

You say you are going to have someone construct it for you. That means you don’t have the machinery and perhaps the skills to do that yourself. Nothing wrong with that, plenty of gun owners out there, who don’t have the skills, who have guns built for them. I am sort of doing that right now myself.

I have the skills and knowledge to build my bowling mortar tube. I don’t have the machinery or experience to work a piece of steel this large. I don’t have the welding skills to fabricate the metal work. I am having others do the work for me.

Actually I don’t have the woodworking skill either. I am learning that and building my own carriage.

In the case of my bowling ball mortar barrel maker, he does not know cannon construction, so I have to tell him what must be done. He has a machine big enough to hold the steel and knows how get it on the machine and do the turning. I don’t!

It is very obvious your barrel maker does not know anything about cannon barrel construction. You must tell him what you want done. You must not rely on his lack of knowledge.

To start off your barrel is larger than the original. That doesn’t make sense. The Original Whitworth had a 2 ¾” hexagonal bore-a type of early rifling. It is kind of hard to find a hexagonal rifled barrel at the barrel store. Some guys just substitute a regular rifled barrel for this project. A good scaled down bore size and less expensive approach would be to use a 20mm barrel of some sort. That would solve several problems. Size-a 3’ bore gun will be big and handful to operate-definitely a crew sized weapon. 20mm would be smaller and more easily crewed by one person. A 20mm rifle barrel is more obtainable and much better for this type gun than a smooth bore. 20mm projectiles are readily available. What would you use for a projectiles in 3 inch smooth bore? 3 inch round ball in a smooth bore breech loaded?.

Some folks build Whitworth rifles using 40mm barrels. The 40 mm is 1.57” bore. The 40mm barrel stub GoW offered up for free here was 48 inches long and weighed 120 pounds. I have no Idea what a full length 104 inch barrel would weigh in 40 mm—somewhere between 250 and 300 pounds. And this doesn’t include the breech ring or trunnions. You are talking about a 3 inch barrel, that would weigh even more.

I suggest you get a copy of the AOP plans for the Whitworth and study them. Learn everything you can about the Whitworth. Start doing your material planning. Run your ideas by us on the board and we will help you get this gun built.

Right now all we can do is tell what you are doing wrong. We would much rather help you learn about this gun and help you build it right!
 

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I have to agree with everything DD has said & emphasise the sourcing not only of barrel but also of components to fire it after. With a project this large... and this is an impressive first project... that you go the extra step to make it fully first rate in every way. YOU may never intend to sell this project gun but a first rate project will protect your investment... even be worth more than you spend.
I will contrast this to folks who regularly show up here with questionable devises, sold to them as "cannons" & which they will have difficulty recovering their costs when they realize the unsuitability. We, here, would much rather point you in the right direction to be a knowledgeable future cannoneer.
Welcome to the forum.
 

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Everything DD and Flagman said. Get a cost estimate for wheels alone, Get a cost estimate for machine work. Then figure the weight of a gun this size.....how will you move it?.....where will you be able to shoot it?....how much will every shot cost?. Black powder is not exactly cheap and a gun this size would eat up a lot of it fast. What do you plan on using for projectiles? will they have to be individually machined? Sleep on it for a night or two and count dollar signs instead of sheep as you are dropping off.
 

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Hey DD. Are you talking about the 40MM Bofors barrel I am getting?

I was kinda wandering what the length and diameters of it was. I knew it said around 120 pounds. But never really knew the length or diameter. I was guessing it was around 42 Inches by the length you said the pallet it was laying on was.

Would be nice to know the dimensions if you have time or even know them right off. I know you may not even have access to that info at this time anyway. I forget whos place you said the stuff was even at at right now. I think a member here? Maybe they could tell me?

Not a big deal as it is what it is now, and I will work with whatever that may be..Thanks
 

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Discussion Starter · #14 ·
I dont intend this reply to be sarcastic or rude so please dont take it that way. Its hard to gather tone of voice in typed words.

Im aware the real ones had polygonal twisted bores and 2.75. Im aware that a 3 inch smoothy is not the same. Neither is a 40mm. I dont mind. I dont need an exact replica, just basic idea.
Im aware carriages need to be built a certain way and that they are expensive.
Im aware the barrel will be heavy.
My builder is a cannon and mortar builder, not just a random machine shop guy. He may build like you guys here, he may not. I asked him if he could do a Whitworth style in 3 inch.

You guys are hitting me with considerations and thats cool but you all skirted the question i asked.
Is there enough metal thickness at the breach to be safe?
 

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Youngblood said:
You guys are hitting me with considerations and thats cool but you all skirted the question i asked.
Is there enough metal thickness at the breach to be safe?
"He's going to use 1026 cold drawn seamless tubes, one on top of the other.
3/8 inch square threads.
My question or concern is the chamber metal.
1.5 inch metal around chamber and 2 inch behind it on cap."

Drawings would really help here..... one consideration is how deep are the threads? That cuts your wall thickness down some..... How long is the area being threaded? Is the breach area reinforce slipped on and welded? it could all be perfectly safe..... BUT...... there are at the moment too many possible variables and not enough data......
 

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Youngblood said:
My builder is a cannon and mortar builder, not just a random machine shop guy. He may build like you guys here, he may not. I asked him if he could do a Whitworth style in 3 inch.

Is there enough metal thickness at the breach to be safe?
Blunt but truthful answer, we don't know. Not enough information is known about your build.

But if your guy is a knowledgeable cannon maker and he has first hand information about what and how you want your build done, then he is in a far better position than us to pass judgment.
 

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One thing that would help is to use stronger steel than 1026; something like 4140 even if in the annealed state is likely much stronger.
 

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The smokeless ratio is about two-thirds. However, I would try to get some engineered numbers before committing.
 

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IIRC, 4140 requires a pre-heat when welding. If you're welding on it. :)
 
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