Safe wall thickness for brass cannon

[Jarikeen]

If one was turning down a small cannon from brass stock, is there a 'rule of thumb' for wall thickness to bore diameter, that will handle the appropiate charge of BP?

 

[andrellj]

"The more complete cannonneer" states that cast iron cannon should be no less than 1 caliber thick but brass I'm not quite sure either. Please post when you do find out if it's not another forum member who informs you.

 

[TheDoubleD]

That rule found in The More Complete Cannoneer applies to all cannons. Diameter over the breech should be a minimum of one caliber in all directions.

The rule is actually from the N-SSA

 

[GunneyG]

If one was turning down a small cannon from brass stock, is there a 'rule of thumb' for wall thickness to bore diameter, that will handle the appropiate charge of BP?

You've been given the rule of thumb; unfortunately there is no rule of thumb for an "appropriate charge," so you are still somewhat in the dark. Also, powder charge for a blank (noise making) load or for a load with shot?

 

[HarborMaster]

Actually there is a rule of thumb for an "appropriate charge" . There is a designated amount NOT to exceed per bore diameter.

How to load a small black powder cannon for blank salutes

Bore diameter
in inches Typical barrel length in inches
(depends on barrel style) Black Powder
Grains
Maximum Black Powder
Ounces
Maximum Approximate *volume fg (ffg**) - powder -
Using a aluminum measuring spoon
(level measure)
1/8 1.5 - 2 L 10 .02 oz 1/8 teaspoon
3/16 2 - 3 L 15 .03 oz
1/4 3 - 5 L 20 .05 oz 1/4 teaspoon
3/8 5 - 7 L 40 .1 oz 1/2 teaspoon
1/2 7 - 8 L 60 .15 oz 3/4 teaspoon
5/8 8 - 12 L 100 .23 oz 1.25 teaspoon
3/4 12 - 14 L 140 .32 oz 1.75 teaspoon
1 14 - 26 L 438 1 oz 2 tablespoons
1.5 25 - 40 L 656 1.50 oz 3 tablespoons
2 40 - 50 L 875 2.00 oz 4 tablespoons
2.25 50 -60 L 1313 3.00 oz 6 tablespoons
2.5 60 L 1313 3.00 oz 6 tablespoons
3 65 L 1750 4.00 oz 8 tablespoons

 

[mike alexandre]

Afraid this seems to have come out a bit jumbled. Could you reformat it please as I'd like to understand it a bit more.

 

[rifleshooter2]

I think this is what Habormaster was trying to send

Bore diameter in inches
Typical barrel length in inches(depends on barrel style)
Black Powder Grains Maximum Black Powder Ounces
Maximum Approximate *volume fg (ffg**) - powder -Using a aluminum measuring spoon (level measure)


Bore Dia. 1/8----Bore Length 1.5 - 2 L------Grs 10 ---------.02 oz 1/8 teaspoon
Bore Dia.3/16----Bore Length 2 - 3 L--------Grs 15 ---------.03 oz
Bore Dia.1/4----Bore Length 3 - 5 L----------Grs 20 ---------.05 oz 1/4 teaspoon
Bore Dia.3/8----Bore Length 5 - 7 L----------Grs 40 ----------.1 oz 1/2 teaspoon
Bore Dia.1/2----Bore Length 7 - 8 L----------Grs 60 ------------.15 oz 3/4 teaspoon
Bore Dia.5/8----Bore Length 8 - 12 L---------Grs 100 ----------.23 oz 1.25 teaspoon
Bore Dia.3/4----Bore Length 12 - 14 L--------Grs 140 ----------.32 oz 1.75 teaspoon
Bore Dia.1-------Bore Length 14 - 26 L--------Grs 438 -----------1 oz 2 tablespoons
Bore Dia.1.5----Bore Length 25 - 40 L--------Grs 656 -----------1.50 oz 3 tablespoons
Bore Dia.2-------Bore Length 40 - 50 L--------Grs 875 -----------2.00 oz 4 tablespoons
Bore Dia.2.25----Bore Length 50 -60 L--------Grs 1313 ----------3.00 oz 6 tablespoons
Bore Dia.2.5----Bore Length 60 L--------------Grs 1313 ----------3.00 oz 6 tablespoons
Bore Dia.3-------Bore Length 65 L-------------Grs 1750 -----------4.00 oz 8 tablespoons


Andy

 

[mike alexandre]

Thanks. These look like live firing as opposed to blank charges. Could you confirm that please.

 

If one was turning down a small cannon from brass stock, is there a 'rule of thumb' for wall thickness to bore diameter, that will handle the appropiate charge of BP?

The first thing you should be asking is do you have the right type of brass for the job. I would reccommend 660.

CP

 

[Jarikeen]

Thankyou for the responses, some good information there. Is the thickness of one bore in all directions primarily because most cannons were cast, and that loads often exceeded the above quantities. Just seems like most of the steel rifle barrels have a wall thickness about 1/2 the bore diameter - mind you, if you are building a replica cannon, best to go with correct dimensions.