Stainless Golf Ball Mortar and Howitzer

[Mortarmer B]

Want to know the possibility of making a scale 12lb. mortar and howitzer out of stainless.  I just didn't see anyone using stainless.  I know it's not historically accurate, but I planned on using some stove black or stove paint to create the cast iron look anyway.  The thing is that I have a heavy duty pump shaft that came out of a sewage pump station.  It's 5.5" dia. and 36" long.  Thought I could get a mortar out of it, then maybe a howitzer too, but I haven't worked the number on how long the howitzer should be for the scale. 

I'm not completely sure what allow it is.  I don't think it's as low as 306/314. 

Just wanted some thoughts on my first project for practice before I invest in brass rod.

Thanks in advance for your time
Bryan

[GGaskill]

Want to know the possibility of making a scale 12lb. mortar and howitzer out of stainless....  It's 5.5" dia. and 36" long.

12 pdr bore is 4.62" which would be too large for a 5.5" dia piece of stock.  Your chamber size should be 1/3 the diameter of the stock (both howitzers and mortars are normally chambered pieces) and the bore size should leave a reasonable thickness just for mechanical strength.  I would say 6 pdr bore (3.62") would be OK. 

A 12 pdr mountain howitzer scaled to 5.5" dia would be 26.92" long leaving a 9" long piece for a Coehorn. 

Ordinary stainless is not as strong as plain mild steel; it is more in the area of brasses.  It would be OK for a muzzle loading artillery piece as long as you use prudence in loading, but it would not be as strong as mild or low alloy steels.

[Rickk]

beer can mortar?

[Mortarmer B]

Sorry, when I meant scale, I didn't mean full scale, but a fractional scale of the full size.   I saw CU Cannons Excellent .pdf document of the shop drawing of his mortar and planned to use it, he did say it was over built, with a wall thickness of .885 at the thinnest, thicker around the bands. 

GGaskill, it seems as though you put some thought into the scaled howitzer.  With a Golf ball sized bore, what OD and length should I "Shoot" for, instead of just staying with the 5.5" stock I have.  It seem like just buying some new steel would be my way to go instead of using scavenged stuff.  Would 1018 stuff be alright?

[GGaskill]

I consider 1018 to be ideal muzzle loading cannon material.  But scavenged material, especially if you know what it is, can be good, too. 

A golf ball bore mountain howitzer could be made at half scale, which works out to be 3.8" max dia and a little over 18" of length.  This is under bore for the scale but not too much.  Check out this thread for some discussion of a half scale mountain howitzer.