Author Topic: Help... (Read 927 times)

no guns here · « **on:** July 06, 2009, 08:55:35 AM »

Okay, I've been on GBO for years and have lurked aroung the cannon board for a while. I ran into a guy a work that is something of a machinist in his spare time. He said that if I could find the metal he would turn a small barrel for me. He has a complete shop in the US but only brought a small lathe here to germany. I would like something in bronze. I'm thinking a small coehorn would be a good start. He said he could handle something on the order of 3" dia x about 9" long. Problem for me is... all I know is the word "bronze". Is there an alloy number or something that would be universal so I can ask around at some German suppliers. I want something that will actually fire a projectile. A golf ball would be great but I'm not sure 3" diameter would work for that. Suggestions? Ideas? Plans? I can handle the bed for it. I can get the hardware made too if needed.

On another note, the same guy found a unit that is deployed. The equipment that is left behind has a complete shop of some kind with two big old lathes. He said the biggest one is for up to 12' stock and the smallest is for 6' stock. Really big implements that weigh tons apiece. I don't know crap about it but sounds like something that could be fun to play with if I had a clue...

NGH

gulfcoastblackpowder · « **Reply #1 on:** July 06, 2009, 09:32:31 AM »

From my research, SAE 660 Bronze is probably the most machinable that would be useable for a barrel, though I'd recommend a seamless steel liner if it is a large bore. For small guns (probably no larger than ~.50 cal in my mind), the liner may not be as necessary, as the pressure levels become similar to a pistol barrel.

Most people don't recommend using brasses, as the high zinc content tends to make them brittle (i.e. prone to catastrophic failure). There are a number of other bronzes which may be better suited for cannon, but most of them have low machinability, and are therefore usually cast.

BTW, don't just take my word for it, as I contracted with a builder on here to make me a bronze handgonne, but he stopped communicating with me when it was almost finished, so I don't actually have any bronze barrels, but it was being made of 660. Others on here with bronze barrels have at least 1" unlined 660 barrels.

dan610324 · « **Reply #2 on:** July 06, 2009, 09:56:03 AM »

3 inch bar for a golfball bore (1,75 inch) is good enough for a coehorn mortar with a sub chamber .
thats no problem at all . you dont even need a liner

GGaskill · « **Reply #3 on:** July 06, 2009, 01:58:45 PM »

Dan,

Can you give him a European alloy to use?

C90700 is a US designation for bronze that is 89% Cu, 11% Sn, plus or minus impurities. That is pretty close to the 90/10 bronze used in US Civil War era bronze pieces.

no guns here · « **Reply #4 on:** July 06, 2009, 09:46:30 PM »

Thanks guys, I was pretty sure I could get away with a GB mortar and a small chamber. I don't want anything big right now. Actually I do... but I have to break the wife in slowly on this. She's okay with rifles, pistols, shotguns, bows, etc... cannons might be a different story. I'll need some plans for a gb coehorn too. Maybe I didn't dig deeply enough on the sticky's.

NGH

brokenpole · « **Reply #5 on:** July 07, 2009, 05:57:38 AM »

Quote from: no guns here on July 06, 2009, 09:46:30 PM

Thanks guys, I was pretty sure I could get away with a GB mortar and a small chamber. I don't want anything big right now. Actually I do... but I have to break the wife in slowly on this. She's okay with rifles, pistols, shotguns, bows, etc... cannons might be a different story. I'll need some plans for a gb coehorn too. Maybe I didn't dig deeply enough on the sticky's.

NGH

You do realize that what you have is an addiction. There is no cure. There is no shot the doctor can give you. The only 12 step program available is buying 12 artillery pieces. Currently, we are not sure if this 12 step program works...but it can be a whole lot of fun!!!

no guns here · « **Reply #6 on:** July 07, 2009, 07:28:10 AM »

Heck, I've got an addiction!!! If it goes "boom" I want one. I'm fully cognizant of my addiction to cannon and I don't even have one. I can't imagine how absolutely cool it would be to have a 1/2 scale something or other in my foyer pointed directly at the door. It would have to be unpainted and shiny with a semi-worn paint job on the carriage. Enough to look "used". Of course it would have to be in firing order. No lawn ornaments for me. I spend a lot of time looking around here and drooling. Tropico's Six Pack just about did me in... still got a strong ticker but I'm pretty sure I was hyper-ventilating... I'm definitely going to have to indulge my addiction.

Wife thinks I'm nuts for some of the things I want. I really have the jones for a big bronze bell too... I don't want a play bell or a toy bell or a train bell. I want something that rolls out a strong BOOOOOOOOOOOONG that will echo the hills. I think something in the 20" range would do for a start.

Maybe it's just an addiction to brass and bronze?

??

No about those plans for a GB coehorn???

NGH

dan610324 · « **Reply #7 on:** July 08, 2009, 10:43:45 AM »

sorry I cant recomend anything in this .
when I was in the steel manufacturing business we just used sis numbers (swedish industrial standard )
my knowledge in this is to old , and today I mix my own bronze when needed .
90% copper and 10% tin , try to find that alloy if its possible .

but if you want to look at some beautiful original drawings from mid 1600 to early 1800 go to :

www.arkeliet.net

when you come there , look for the word bildearkiv in the upper right corner of the screen , leftclick there
when that opened just scroll down to the bottom of the page , there you find some original artillery handbooks .
click on the book of your choise and it will open and you can see high quality photos of each page .
there you will find lots of drawings , there is so many beautiful designs to choose from .

all pictures are enlargeable .

gulfcoastblackpowder · « **Reply #8 on:** July 08, 2009, 06:37:00 PM »

THe mix of 90% copper 10% tin is the traditional ancient bronze formula, and can be very good for cannon, but it's machinability is low, which is why I recommended the 660 (often called bearing bronze), because it has been tested in a number of small cannon and it has good machinability. If you wanted to cast, the 90/10 would probably be the way to go.

GGaskill · « **Reply #9 on:** July 08, 2009, 06:49:22 PM »

I'll need some plans for a gb coehorn too. Maybe I didn't dig deeply enough on the sticky's.

They are in the stickies but I'll post them here, too.

GGaskill's Golf Ball Mortar Contest Entry

CU_Cannon's Golf Ball Mortar Contest Entry

(image was posted on a short term hosting site)
Cat Whisperer's Golf Ball Mortar Contest Entry

DD's Golf Ball Mortar Contest Entry

dan610324 · « **Reply #10 on:** July 08, 2009, 08:21:36 PM »

what is the exact alloy content of the 660 bronze ??
hope it aint any silicone or wismut in it for example .

GGaskill · « **Reply #11 on:** July 08, 2009, 08:25:58 PM »

SAE 660 is also called C93200. Click the link for details.

dan610324 · « **Reply #12 on:** July 08, 2009, 08:49:09 PM »

its similar to what you americans call gun matal , except for its very high lead content.
the lead gives it very good machining caracteristics , but Im not sure how much the lead does for its strength.
but it sure aint adding any strength .
anyone who have a good knowledge in metalurgical issues ?? mine is just basic .

the 90/10 alloy isnt having that bad machinability , just use sharp hss tools

gulfcoastblackpowder · « **Reply #13 on:** July 08, 2009, 11:22:36 PM »

The closest I can find to commercially available in 90/10 is 89/11: c90700

C93200 (link provided by GGaskill), has similar characteristics in strength and modulus of elasticity, but has machinability of 70 compared to 20 (meaning 70% and 20% the machinability of free cutting brass, respectively). I'm not a machinist, but according to the ones I discussed it with and the research I've done, this makes a significant difference in the ease of manufacture by machining processes.

dan610324 · « **Reply #14 on:** July 09, 2009, 12:12:12 AM »

yes of course it is a difference , the only reason to add the lead is to get better machinabilities ,
but we are still talking about turning one mortar for hobby purpose ,
and not to produce 2 000 000 pcs of something .
I have done some machine jobs to my castings without any problem or difficulties .
both drilling , turning and milling , if you just have sharp tools and dont try to hurry up to much its no problem .
as it is a cannon that will be used and not a desktop showpiece I would recomend to think more about safety then the mechanical characteristics during the production .

so I would go for the c90700

but as usual its just my ideas .

gulfcoastblackpowder · « **Reply #15 on:** July 09, 2009, 08:53:31 AM »

Very well, I defer to your expertise. I have no experience in the manufacture of barrels, so yours trumps any information I've gathered second hand.

dan610324 · « **Reply #16 on:** July 09, 2009, 09:02:05 AM »

Im absolutely not any expert, just have made some barrels during the years .
but in this case where its just one barrel that should be produced I think its better to use a well known alloy of suitable quality also if its a bit more difficult to machine .

no guns here · « **Reply #17 on:** July 10, 2009, 01:42:36 AM »

thanks guys... I've got a line on a scrap metal yard on the other side of Stuttgart. I'm going to take one of my buddies that speaks Deutsche like a German. At least we have a starting point. May be a week or two before we can get time off at the same time to go. At least I have a starting point now. I printed off some of the pictures and drawings for the guy who will do the work. He's actually sort of ready and excited to try this. Dang, if we get that done I'll have to hit the wood shop and work on the bed... and then I'll HAVE to get my blackpowder and reloading licenses so I can buy the necessary supplies. It could take a while before I can actually make noise... nah... I know a guy who does BP so I can get him to come with me to the range. Still might be a couple of months before... I'll just have to stay focused... Pigs need to be hunted... Deer need to be killed... focus.... focus... No Mike you can't shoot deer with the cannon. I'm sure that is illegal in germany... hmm... Focus... FOCUS!!!

NGH

Ex 49'er · « **Reply #18 on:** July 10, 2009, 03:59:56 AM »

Quote from: no guns here on July 10, 2009, 01:42:36 AM

thanks guys... I've got a line on a scrap metal yard on the other side of Stuttgart. NGH

Keep an eye out; the scrap dealer may have some old rifled barrels lying about.
Could be some easy pickens there.

kappullen · « **Reply #19 on:** July 10, 2009, 07:34:15 AM »

Quote from: gulfcoastblackpowder on July 06, 2009, 09:32:31 AM

From my research, SAE 660 Bronze is probably the most machinable that would be useable for a barrel, though I'd recommend a seamless steel liner if it is a large bore. For small guns (probably no larger than ~.50 cal in my mind), the liner may not be as necessary, as the pressure levels become similar to a pistol barrel.

Most people don't recommend using brasses, as the high zinc content tends to make them brittle (i.e. prone to catastrophic failure). There are a number of other bronzes which may be better suited for cannon, but most of them have low machinability, and are therefore usually cast.

BTW, don't just take my word for it, as I contracted with a builder on here to make me a bronze handgonne, but he stopped communicating with me when it was almost finished, so I don't actually have any bronze barrels, but it was being made of 660. Others on here with bronze barrels have at least 1" unlined 660 barrels.

Golf Coast,

660 bronze is a bearing bronze, and in my mind may be too brittle, not knowing where it is going.

The Handgonne is, and has been done for a while.

You have to negotiate with SWMBO.
SWMBO's afraid of selling guns for legal reasons.

I apologize for your continued heartache.

Kap Pullen

gulfcoastblackpowder · « **Reply #20 on:** July 10, 2009, 09:39:33 AM »

Fair enough, Kap. It's unfortunate that we didn't know that SWMBO would put a block on the sale before you made it. I don't know any way of convincing her, so I don't suppose the sale will ever be completed. Have you tried it yet? I'd love to see a final polished picture.

Quote

No Mike you can't shoot deer with the cannon. I'm sure that is illegal in germany...

Hmm I seem to remember a minimum caliber for deer in FL, but I don't think there was any mention of an upper limit...