i'm wanting to make a cannon, originally i was going to buy a premade one from hernironworks made of cast iron, but i decided that turning one on a lathe at make ict might be both more cost efficient and much safer (as cast iron is not great as a cannon material)
the steel rod needed to make the cannon would weigh around 810 pounds with a diameter of 9 inches, and after shaping the outside it might drop considerably, like to maybe 600 or so pounds since it tapers
after that i'll need to bore out a hole in the cannon 3 inches in diameter and 37.5 inches deep
assuming i can use a metal lathe with that high of a carrying and length capacity, and $500-$700 to spend on tooling, how would i go about doing this?
heres a rough drawing of the cannon, the handles and trunnion will be added afterward
You will need a lathe that has at least 60" between centers, depending on your drilling setup.
Here ist a guy that made a Cannon 1/20 the weight you are planning:
Okay, I'll bite... Do you have access to a lathe that will handle work of this size, and have you ever run a lathe before? Have you sourced the material, and what are you planning on using?
i mentioned make ict in the op thinking it was business chain but i guess not, its a place that lets you work with machines for a membership, if that doesnt work theres also another similar place i can go to
the material will be 1018 steel, i found an online source which i can pay $1250 for, but due to possible shipping costs i'm gonna seek out a local supplier first
never ran a lathe before though, which i know is the biggest problem with the plan, but i have a friend who works a lot with car parts who's gonna make it with me, i know this doesnt sound realistic, but i'm hoping that if i throw enough money at it it'll work
if it doesnt look like things will work out, i wont buy the materials and i'll just buy the cannon i initially planned to buy for $2000
That's a tall order with neither of you ever running a lathe. I'll stop short of being that guy that seeths and says "If you have to ask you can't do it!" but I doubt you're going to save the money that you think you are. You need to check and see if your shop place has a big enough machine as well. If you want to bore something 4' long you'll probably need a bed twice as long. Just something to think about.
yea, to be honest if i cant find an experienced hobbyist machinist at the shop who's interested enough to help i wont do it, but if i have the option to turn a cannon myself i'll take it since its a small cost compared to the possibility of a cast iron cannon becoming a pipe bomb due to lack of strength
I tried to bore a cannon once but I could never get the Fourier series to work out.
what?
i'm thinking that due to the massive length required to bore a hole in the cannon, i might have the boring professionally done
it seems that metal lathes that would max out on just the size of the cannon without the extra space needed for boring it would be common, so i could shape the cannon myself and then take it to a machine shop to have it drilled
i'll also turn a small mortar on the lathe before i do a full cannon to test my abilities
My dad built a 12” cannon out of aluminum
Heated it and inserted a steel liner / sleeve
Turned out very nice. If my memory serves me it was .36 caliber. I was less than impressed when it fired
try making a smaller one, see how that works out. It'll probably be easier, it will cost less, you'll get an idea of what you're doing and you can see if you want to make a bigger one.
yea, like i said i'll turn a mortar out which would weigh considerably less
when i say tooling i mean the lathe bits, that $500 is assuming i can already use a lathe, which i dont think is unreasonable
and if it just doesnt work out, i'll simply buy a premade cannon, but what use is it to rail me for simply asking?
>$500-$700 to spend on tooling
> to bore out 70lbs of steel
Just moments before OP made this post
This.
The whole reason cannons were cast was to avoid machining. And one does not simply "cast a cannon"
Go to scrapyard, buy thick walled pipe
Weld a breach cap on one end
Drill a fuse hole
50$ cannon OP
Cast it as close to perfect as you can get it, then bore out the centre smooth. That's how the British did it in the Napoleonic era
I remember seeing someone make a mountain howitzer replica and walked through how he did it, are you copying his plans or making a new one?
the link to where he did it is www.buckstix.com/HowitzerBarrel.htm
i've looked at his method but i dont know where i could get the steel tube to do it, also the cannon that i would buy if i werent going to make it would be a mountain howitzer anyways, and i'd rather make something else
he also uses welding, and i'd rather have a solid cannon instead
yea i know the lathe would need to be very large, i just need to know how to use the lathe to bore the hole
all i know is that i have to use a spade bit and a boring bit, and then turning the outside like you normally would with a lathe
i've thought about casting from bronze but i dont know how i would go about lining the cannon and i dont trust whatever ghetto setup i come up with to not result in a bunch of airbubbles or spill molten metal on me, and a crucible that can hold 600 pounds of bronze wouldnt be cheap
>$700 for tooling
>boring bar with 37.5" of reach and a 12.5:1 overhang
top fricking kek
how the hell am i supposed to know elitist c**t? i can get a fricking car engine for that much, is it really so wrong for somebody who doesnt know much to think that a single tool wouldnt cost more? i'm used to making everything by hand on a forge not machining
OP you will most likely spend way more money than you would if you bought one, and probably would make you wanna die.
first off, assuming that you can find a piece of steel locally for 1250, plus 700 for tooling that still puts you at 1950, which is practically enough to buy the premade one, to address your concerns about the quality of the hern cannons, you clearly MASSIVELY underestimate the strength of modern grey iron, hern has been casting cannons for 50 years if one of them was going to explode it would have done it by now.
to expand it a bit more, 700 for the type of tooling that is required to accurately bore a hole of that size is laughable, you're looking at at least double that amount, if you wanted to do it on the cheap, a twist bit would work, but that would most likely get you a cannon that can't hit the broadside of a barn, you most likely want a carbide spade bit, but i cannot fathom how much one of the size you need would cost, likely you want a twist bit that is undersize, then go through it with a boring bar, that setup would give pretty nice results, and might fall within the 700 budget, if you buy the cheap shit.
also you need to know what kind of machine you are using, does it have a coolant feed? if so, does it have a coolant fed tailstock? because frankly i wouldn't even attempt boring that if it didn't, and as for shaping the outside, a coolant feed would probably knock a few hundred dollars off of the tooling costs, you could slow the lathe down to preserve tooling, but you would be there for an eternity.
and PLEASE for the love of GOD, get some experience running a lathe, there are so many small things about turning stuff that i cannot tell you, also if your friend has some experience machining, great, if you're just having him along because you think the skillset of a machinist and mechanic are interchangable, you are entirely wrong, mechanics put things together, machinists create the stuff that they put together, very different.
well, my concern has been surrounding the mountain howitzer 3 inch
its a 3 inch cannon with a straight bore rather than a howitzer with a reduced powder chamber
and while this means i could shoot it like a normal cannon, i'm worried that since it has the same dimensions as 2 1/4 inch bore mountain howitzer, that it would only be able to handle half a pound of powder charge instead of a full pound, since it shoots a 3-4 pound cannon ball and the weight to charge ratio should be 4:1 or 3:1 for a cannon
to be honest though i am considering ditching the idea so that instead of wasting a lot of effort into making a cannon, i can put that effort into making different ammo types for it, like machining aluminum molds to cast rifled zinc slugs or armor piercing sabots
also, i asked for a quote from a machining company what it would take to bore a 3 inch hole in a 9 inch diameter stainless steel rod (stainless was the cheapest they had), and while over my budget, they only asked 4500 to do it (and considering this is twice the weight and size of the howitzer, i dont think its a bad price at all), while the closest in size and weight that hern offers is 4100 (the alamo 4 pounder)
>if you're just having him along because you think the skillset of a machinist and mechanic are interchangable
i oh i know he's just a moron like me who wanted to do stupid shit together
Again, you’re underestimating the strength of modern grey iron, also you have to remember these guys are a company, if it was found that a certain design was incapable of handling the powder charge it was designed for they wouldn’t sell it, because if it blew up then they could get sued, and then their entire company goes down the shitter, if it says that the cannon you’re looking at can only handle a 1/2 pound powder charge then buy a cannon that can handle what you want if you’re not sure about it then call them, I’m sure they have tested what these cannons can safely handle, at the end of the day buying one will be simpler and cheaper no matter what, I would save the effort and put it into something more worthwhile like making your molds
>because if it blew up then they could get sued, and then their entire company goes down the shitter
he doesnt know
Problem is, that would never hold up in court, it’s a company that sells cannons, they are marketed as cannons, implying they are ready to be fired, like a cannon, and say someone blows up one of these cannons and dies, who is a jury gonna side with? The grieving family or the company who sells poorly made “iron castings” that are clearly supposed to be cannons, the real kicker is that some of their cannons are rifled, why would a display piece need rifling? Why undergo a costly time consuming process just to end up with the same result? The “castings” true purpose is evident, and therefore the company should either make them non functional or ensure the structural soundness of the cannons.
>therefore the company should either make them non functional
they arent functional though, they get sold without the vent liner
you cannot shoot them without modifying the cannon
whether the agreement you sign still holds up i dont really know
Definitely cast material, some cast steel or something, combined with machining the innards. Its a lot of tooling spent on boring a hunky chunky block of steel to shape unless you cast it.
i've looked at the possibility of casting it again, and i do think it might be easier than machining it
i doubt i could cast steel very easily, but bronze would be preferrable to cast iron because of its properties
and then instead of going with the half inch liner that hern builds their cannons with, i could use a 1 1/4 inch liner instead, which considering its steel i almost wonder if it would be enough to absorb the shock of firing on its own
but i could just cast bronze over the liner, and make a model of the cannon out of something easy to work with like styrofoam to form the mold out of
but heres the greatest question
where the hell would i find a graphite crucible that can hold up to 600 pounds of molten metal
i already have a decent idea of how i would make a structure out of bricks to cast the cannon for me that would completely eliminate handling it manually and having the threat of spilling it, i just dont know how i would get a crucible that large
actually, i've watched this video https://www.youtube.com/watch?v=Lr6jGWD2DAE
and its given me an idea of how the crucible should work
a subtle thing to miss thats crucial to how their foundry works is that the crucible seems handmade, and its made in a way that a seal can be broken in it by hammering a steel spike through it
by making a crucible like this, i wouldnt have to worry so much about a handmade crucible being too fragile as it would be completely stationary rather than being lifted and tilted, having to support 600 pounds on its own
in the video i dont really like the safety of molten iron gushing out of the spout due to its own weight forcing it out, so i would change a few things
for one, i would dig a hole and put the mold in it, and have the crucible cast near ground level
i would also surround the area surrounding the hole with fire brick to prevent splashing
if possible i would also like to somehow heat up the mold before casting to prevent the metal from hardening on the sides of the cast before it reaches the bottom and causing defects, which i could do by blowing flames on the inside of the mold
and while i want to do a practice cast before a full cannon, i believe i would only get one use out of a furnace like this each time, since i would be building it out of fireclay like an older bloomery rather than all firebrick, and the crucible would be unable to be used twice if i have to drive a spike through it
so i'll probably make a second scaled down version of the furnace instead
as to how i'll make the crucible, it seems its made from a really cheap combination of clay and different powders, but that firing it at high enough temperatures is difficult
You can turn and bore round bar but the smart way to make a toy you won't really use often is do what bowling ball mortar hobbyists do.
Buy high pressure gas cylinder used. MUCH cheaper than machining. Saw off the valve end then drill touch hole or even mount a classic flint or percussion lock. Put your material money into the carriage.
Casting a large barrel is silly unless you fully understand foundry because a void can kill you. Turning round stock is reliable and avoids noob foundry mistakes. There are plenty of suitable large lathes and they make far more useful parts than some improvised crucible chosen out of ignorance.
Acquire lathe (which can be a very old one since it doesn't need to be a screwcutting lathe though those are reasonable and you can resell it later), source suitable steel which can be a very large scrap shaft. Bandsaw shaft to length (a local shop can do this if you don't want to own a horizontal band saw) and have at it.
Demilled military cannon barrels can make slick breechloaders:
https://www.go2gbo.com/threads/20mm-cannon-french-75-carrage.428266/
Hobbyists have solved EVERY possible question OP may have so study success rather than make assumptions out of ignorance. Getting shit done requires knowing not assuming, and everything about making cannon is known.
i think that a combination of using a much thicker steel liner than whats necessary, lower powder charges, and taking precautions to avoid casting deformities will make the cannon stable enough that even if there was a void, it would be safe to shoot
the steel liner alone is rated for atleast 60k psi, and by going off data from a muzzleloading calculator it would barely pass 15k, which even if its not accurate i doubt that it would be so off that a single charge could break the liner before its even cast over
and once you cast the iron over the liner, it would be many times thicker
im also accounting for the weakest part, the breech, by adding much more material to the back than is necessary
i decided on a 36" long 1 1/4" thick liner with an OD of 5 1/2" and ID 3", which will be fitted over a 3 inch long steel plug and welded at the back (which i'll hire a professional to do)
the cannon itself is gonna be 45" long, so there would be an entire foot of solid metal between the rearest part of the cannon and the back of the chamber
i could also reinforce the breech by shrink fitting a few thinner pipes over the liner, or by adding a 9" diamter pipe to the mold so that it reinforces the cast iron