big safety question.

[dirtdobber1919a4]

i have been working off and on towards finishing my golf ball howitzer.  im now wondering about the safety of it. the chamber is 1.25 diameter by 1.5 long.  my wall thickness is only .5. the whole thing is made of 4140 cold roll. can i even safely shoot golf balls out of this thing? if so what is the max load i can use? or have i just mad a great noise maker and nothing else?

[armorer77]

Have you done any heat treating ? Any welding to set up stress patterns near the chamber ? Armorer77

[gulfcoastblackpowder]

Is the wall thickness the thickness around the chamber, or the balance of the barrel?

[dirtdobber1919a4]

the sub chamber was pressed in then the cascable and know were welded on. at the chamber the wall is the thickest, due to a sub chamber. the rest of the barrel has a .300 thickness.

[dan610324]

way way to thin if you ask me
the walls surrounding the chamber should equal the chamber diameter as a minimum
ok, now many will say that its not neccesary

yeah maybe not , but do you want to be safe or sorry ??

someone maybe will load it with smokeless powder in the future , you never know .

your grandson or grand grandson maybe will blow up both himself and his family

the decission is yours
I can only give you recomendations

[gulfcoastblackpowder]

I agree that the walls around the chamber should be at least equal to the diameter of the chamber.  That's the biggest safety requirement in a BP cannon, and one I wouldn't want to deviate from.  Having a powder chamber, the walls of the bore itself can be a bit smaller (as in a howitzer).

[dirtdobber1919a4]

thanks for the advice. always better safe than sorry.  i guess i have made a nice salute gun then?

[oyvind]

thanks for the advice. always better safe than sorry.  i guess i have made a nice salute gun then?

whether it is to be used to salute, walls surrounding the chamber should always be equal the chamber diameter .
You never know what the next owner will do with it!

[dirtdobber1919a4]

ok. i can live with the fact that i have a nice piece of wall art.  i now know better and can start a new one that can actuall make smoke and noise. thanks.

[dan610324]

check around here and you will find lots of good designs

a good advise is to decide first what model of cannon you want to produce
then check what material you got awailable or can get to a fair price

when you got that info you can start calculating on scale and bore size

for a golf ball cannon you need minimum a 5 1/4" diameter bar

[KABAR2]

 

ok. i can live with the fact that i have a nice piece of wall art.  i now know better and can start a new one that can actuall make smoke and noise. thanks.

Can I recommend one thing for your wall art? fill the bore with an epoxy this way

some future generation doesn't try firing it.....

[gulfcoastblackpowder]

Another approach that seems to work well is to determine what you want to shoot.  Once you have a projectile, you can determine the size of stock you need.  If I were making one right now near the size you were working on, it would probably be around golf ball size, since projectiles are so readily available.

[subdjoe]

You could always insert a liner.

[dirtdobber1919a4]

i absolutely love the 12 pound mountain howitzer.  i want to build a golf  ball scale one.  but dont want to have it be almost 6" diameter.  i planed on boring the round stock all the way through. machine a sub chamber and cascable in one piece. have the sub chamber a resitiance fit, then weld them on together, thus a smaller over all diameter. would that be ok?  1.72" bore with a .75" sub chamber?
 i dont want to hurt myself or anyone else, breathing is a habit that i dont plan to kick for a looooong time. 

[dan610324]

if you got the knowledge and posibility in turning I cant understand why you should make it in 2 pcs .
it will be much stronger if its made in 1 piece

a 3" bar is what you need to make a gb howie if you scale down the original drawings
but the 1849 12p howie is one of very very few that  NOT  follow the usual chamber/wall ratio

so I would choose a 3,5" bar and scale the outer from that dimension just to add some extra strength to it