New to cannon building

[bdmtm29]

I have never built a cannon before and want to build a golf ball cannon. I have a 2.5" OD piece of cold roll steel. I was thinking of making a combustion chamber of 1" X 2". That would leave me 3/4" of wall thickness for my combustion chamber. This will be welded to a piece of 2 3/8" sch. 160 seamless pipe. The pipe has an ID of 1.730" and a wall thickness of .330". My question is will this be sufficient enough for the build?

[Cat Whisperer]

bdmtm29  -

WELCOME to the board!

I'm a little confused as to how it's going to fit together.  End to end would put the weld right where you don't want it.  Tuning the cold rolled to where it can be 'shrink fit' (heat the seamless and press the powder chamber inside it) would work.

[dan610324]

I think its a little bit to thin walls , both chamber and the barrel .
but the cost for the iron is the least expensive in a cannon build ,
why not try to find any better (thicker) pieces of iron ??

could you please show a sketch of how you was thinking the construction .

maybe you could use the seamless pipe as a liner and do as cw said , shrink fit the chamber in the seamless pipe .
then reinforce it with a outer jacket that you get a parrot style cannon , then you are close to a good cannon . but still I think .330" is a bit to thin .
 
please remember a rule of thumb :
wall thickness in the breach area should be minimum the same as the chamber diameter
wall thickness in the muzzle area should be minimum 1/2 the chamber diameter

better to have it a bit overbuilt , then you know that it isnt dangerous .

[Double D]

Is schedule 160 pipe seamless?

[bdmtm29]

So instead of a 1" chamber, would going to a 3/4" chamber work?
  Yes, I was going to weld them together end to end. But after seeing what you all have to say, I think I will have it milled down to where it will fit into the bore. I am not planning to use a very big charge and all I want to fire out of it is golf balls.

 I really want to thank everyone for their help and input.

[Cat Whisperer]

Using ONLY golf-balls it doesn't take much.  The problem is how to control its use by whoever in the future.
By making a much smaller powder chamber one would at least give a indication of recommended powder charge.

In golf-ball caliber mortars, 30-100gr of fffg is plenty.

[Double D]

Nothing wrong with creativity or innovation, but for a first build it's probably better/safer to stick with proven designs. Go to the top of the forum an look for the safe loads and cannon plans post.  In that post you will find links to several proven golf ball gun designs. 

If you build one of those designs  you will get the basic design ideas down and should be able create your own design after that.

[bdmtm29]

What if I could get my hands on a 5" to 6" old boat propeller shaft? It is maid out of stainless steel. By using that I figure I could make a really nice cannon that would pack quit a punch. Could someone send me some good plans that are pretty simple. Thanks again.

[GGaskill]

You should look at the prices of large and long drills before making any commitments.  Even Chinese tooling in large sizes is expensive.

And 5" and 6" steel round is very heavy.

[Cat Whisperer]

What if I could get my hands on a 5" to 6" old boat propeller shaft? It is maid out of stainless steel. By using that I figure I could make a really nice cannon that would pack quit a punch. Could someone send me some good plans that are pretty simple. Thanks again.

This is the beginning of the addiction.  EVERYthing cylindrical or hollow becomes a candidate for a cannon or a mortar!  Good job!  You're getting into it.   

I stumbled into a 5" diameter 18" long piece of cold rolled for about $5 - the old man used it to roll down vynal tile.  It WILL shoot something someday.

[seacoastartillery]

     bdmtm29,   take heed to GGaskills comment:  "And 5" and 6" steel round is very heavy."  As an example of how heavy this size range can be, our first cannon we made for sale, the 1/6th scale 100 Pdr. Parrott Rifle, started life as a 29" long X 5.75" Dia. 4150 steel round.  These weighed 219 pounds before machining!  Finished weight is only 45 Lbs yielding bags and bags of lathe turnings and milling machine chips.

     Still though, we would not try and dissuade you from using the heavy piece as it will, after all, produce a larger cannon with more curb appeal and capable of snappy golf ball shooting and a very respectable report.  Please keep us informed.

Regards,

Tracy and Mike

[Double D]

Becareful with what you think is stainless steel propeller shaft , it may be monel a Nickel copper alloy.  It can be difficult to machine and  must be worked very slow to avoid heat and work hardening.

I'm not sure if monel is strong enough for cannon barrel makeing.  Some else can comment on that.

[Victor3]

Becareful with what you think is stainless steel propeller shaft , it may be monel a Nickel copper alloy.  It can be difficult to machine and  must be worked very slow to avoid heat and work hardening.

I'm not sure if monel is strong enough for cannon barrel makeing.  Some else can comment on that.

 I'll second that. Monel is awful stuff to machine, and boring it is a real drag.

 I don't think I would use it for a cannon barrel.

[GGaskill]

Monel physical characteristics (alloy unknown):

MECHANICAL PROPERTIES
Tensile strength, Ultimate    550 Mpa (79770 psi)
Tensile strength, Yield    240 Mpa (34800 psi)
Elongation at Break        48%

Marginal although highly corrosion resistant.

[CaptTHighbiter]

 We work with 400 and 500 Monel all the time. It is corrosion resistant - to Sea Water.  Not sure about  BP fouling. 

400 monel tensile is around 80 KSI min

500 ( or K-monel) is a lot higher, since it can be heat treated by age hardening and then soloution annealing.
Can be made to go as high as 150KSI.  The only way to tell the difference between the two is a hardness test and perhaps a chem check at a lab.

Very tough material to machine!