Cannon barrel or fence post?

[civilcannon]

One of my good friends recently came across a good find, (free of course) . One of the local milk dairy's that produced their own  plastic milk jugs dipsosed of some of the machinery that was  used for this purpose. He found (2) 7-1/4" Od x 3" ID about 7'- 6'' long sections of steel pipe that were used to make milk jugs.The bad news is that they have a series of holes about 1/4 dia. drilled in a radial pattern (6). around the circumference all the way thru the outter wall , at 18 inch intervals the whole length of the tube. Then it gets worse, also the tubes each have an internal steel auger frozen in place with solidified plastic hardened the entire length of the piece.

Some of the suggestions I've heard so far include building a long trench fire below the tube to slowly melt and soften the old plastic ( we have been told that this type of plastisc melts at a low 180 degrees F) At the same time, rig a come-along to the exposed end of the auger to extract this piece. If that works how would this affect the strength to the tube? It would only be used for reanactments with powder only no live fire. And how would you plug or fill the many holes? I thought about driling and tapping for high strength, hard, fine thread  bolts welded on the exterior ? then clean up the interior with an internal boring bar. He has a next door neighbor with an industrial machine shop with a lathe large enough th chuck up one of these pieces. My friend wants to build a Blakely style gun with another piece of pipe welded over the breach as a reinforce. The breach plug would be pressed in and welded as per the proper thickness formula . Same with the trunons. This is about a thousand dollar piece of pip if you had to buy it new, sow it might be worth a try ? or ir it only good for a fence post? Any ideas?. Also if this works a might get a shot at having enough left over for my 2.9 inch confederate rifle.

Thanks: civilcannon

[Cat Whisperer]

I'll take an educated guess.

What you have is called a bi-metalic tube.  (The world's largest manufacturer of them - until it joined with it's biggest competitor and got larger - is here in Pulaski (Xaloy).)

The tubes (here) are often made of 4130 or another softer steel.  The cylinders are cored and then the inside is coated with a VERY hard (abrasive resistant) coating consisting of a propriatary mix.  The mix looks like coarse gravel, is placed inside, plates welded on the ends and the whole is revolved in a furnace to give a thin even coating.  Then they are honed to a smooth inside surface.

A screw goes down the center, band heaters around the outside (holes may be for thermocouples to monitor temperature or may if large enough be for cartridge heaters).  A hopper on one end feeds the material into the screw, it's heated - melts and is conveyed under pressure to the other end where is the nozzle or fitting to where it's used.  Generally used in two industries - plastics and food.

I've made mortars from the 4130 and so have a number of others around here that work at Xaloy.  Stainless is also used.

FWIW.

[Double D]

I you are thinking of using a section of this tube with plug holes, don't.  This would be no different than a seamed barrel and every where you have a plug hole in the bore you have a round "seam" .  You could line the bore and make some gun tubes. 

Best thing to do is work between  the holes.  Breech plug can go in and cover the plugged hole area.  This looks like some prime stuff for 6 PDR mortar tube

I have a piece of steel 6 1/2  x 12 iinch bored out for 6 PDR that I want to build a scale model of a 10 inch seacoast mortar like this.



You could easily make the same thing in 12 PDR. 

You could almost build a full scale 12 BPDR Confederate Mortar.

I don't have scale plans for a Mtn Howizter but I would be surprised if you couldn't do a  1/2 scale.

Lot's of Ideas.  Try to work with what you do have and not what you don't have.

[civilcannon]

Yes that appears to be what we are dealing with ,Thanks duoble D, I like the morter idea, this looks like a good project for a long cold winter.The seamless liner (3'' dia 1/2  wall seamless high strength steel),looks like the best plan for the longer barrels  since we have about 15 feet of this tube, more or less to work with,(you can never have to many cannons ), but you still half to fill the holes from the liner to the outter surace. do you agree that the (thredded studs left short about 1/4 inch, then welded over at the surface) would be the best way to fill the open holes?

civilcannon

[Cat Whisperer]

I would avoind any parts with holes.

But in any case, IF it is 4130/4140 welding it takes preheating to preclude cracking - have the welding done professionally.