Solid steel, not iron mortar tube?

[entsminger]

This may be a dumb question but I seem to have no shortage of those. If steel liners are a safety nessesity when building a cannon why not pour the barrel of a reproduction 8 or 10 inch mortar ( or other cannon) from solid steel not iron? Is it a milling issue? Is steel to hard to turn in a lathe or is it a cost issue with steel being more expensive? I would think a solid steel 10 inch mortar would be virtually industructable plus you could easily weld to it?

  Scott

[Double D]

Scott,

First let me ask have ever seen one of those mortar in person?  I know the is one in Balitmore and another down at Petersberg.

Most likely that is exactly what people like Paulsen Bros are doing, using steel.

It's only the cast iron and bronze tubes that require liners.  

To cast a piece of steel or iron that big you need some serious big equipment casting equipment. A 10 inch seacoast mortar will be in excess of 11,000 lbs when finished.

Then machining the trunnions and bore require another set of equally big machines.  Not the usual home shop machinst garage tools.

Again using the 10 inch seacoast mortar example you are going to need a lathe with greater than 40 inch swing and more than 46 inches between centers, just to hold the piece. Add another 36 inches of bed to carry tooling.  Using the numbers to describe the lathe you would need a  42 x 86 lathe...Kap do I have my numbesr right?   That's a 7 foot bed.

That is a BIG lathe.  

You keep referring to the family in wisconsin that built their own mortar.  We have posted a link to that mortar here before. I'll see if we can find it. Does anyone have a link to that site?

Drop those folks an email and ask them for advice.

[entsminger]

I've seen several 10 and 8 inch mortars in person. Here at Ft. Mcnair in Washinton DC they have about 4, 10 inch 1861 mortars and a 13 inch tube. They have a wonderfull collection of other cannons as well. Unfortunatly since 911 it is hard to access them. I've seen some 8 inchers at Skirmish shoots. Arron Frederickson and his sons are the lucky fellows who have a machine shop where they milled their own 8 and 10 inch mortar! I did briefly talk with them on the phone and I think they said they made theirs from a stronger form of iron than gray iron of the civil war, I forget the metalurgy numbers.. God I'd love to go there and see their shop and how they do it. Can't afford the trip now. I also think Paulson Brothers and Herns make theirs from a superior form of iron.. Why not steel I don't know???I think Cannons online makes theirs from ductile iron/steel. I don't quite understand the difference yet other than it's weldable.
  Yes I know I'd never have the giant tools,lathes ,milling machines to make such a huge mortar . I guess I'm just trying to figure out a way to ever own one of these mortars with out just outright buying one which I'll probably never be able to do. Maybe I could work with someone to build one?? Who knows?Even if I never will be able to afford one I can at least dream and  I am interested in knowing all I can about their construction and materials so I keep asking stupid questions that I can't find answers for elsewhere.
   I've always liked big things. Funny ,but I find the huge weight of these mortars attractive not a hinderence! It sets them appart. I think the fun/challange of shooting them would be equal to the fun of moving them. I know, pretty crazy hugh? Nobody would steel one of these babys from your front yard either! I'm hoping someday to get a solid 15 inch Rodman cannon ball to add to my small collection of cannon balls. I just love the huge size of it!

 Not knowing anyone personally who is interested in making cannons it is sort of hard to get information on the subject. This forum is all I have to talk to.  When I get done with all my investigation of mortar making I may write a book.....Mortar building for Dummies....

  Scott

[Double D]

Never ever give up your dream...who knows.

In the meantime build yourself a smaller mortar and start your learning curve. Learn how to build and shoot mortars and as circumstances present work up the scale.

[The Shootist]

:shock: If you had the huge casting, the machine work could be done with something like a Climax Portable Boring tool.

The Climax is used for things like boring Steam Loco cylinders without removing them from the engine.

You could make one, by boring a pilot hole at the rear of the chamber, then make a boring bar that slides up and down a guide rod inserted into this hole. Auto shops used to have a boring machine that bolted to the deck of an auto's engine block and could bore a single cylinder in place.

The touch hole is easy and could be drilled with a hand drill if you are carefull.

The trunions don't have to be trully finished at all, but could be smoothed with a an internal reamer(like a threading die, minus the threads). Or a horizontal mill could be made with a lathe headstock, and a section or 2 of heavy I beam to use as ways.

If we can be resourceful in where we get materials, we can also be resourceful in our machining methods. In the guidlines the windage needed for a huge-bore peice is so loose that tolerences are very forgiving anyway.

Grant

[Cat Whisperer]

Grant -

WELCOME to the board!

Intersting ideas on methods of doin' it.

I like it when the word 'can't' doesn't show up, just ideas on how to!

[Santa Dave]

I saw a story on the San Diego Chargers "Cannon Man" unfortunatly they were NOT interested in the cannon. in the few glimpses we got I saw what appeared to be either 1/2 or 1/3 scale, mounted on a field cariage and CHROME! Don't cannons suffer from hydrogen embrittlement too? The way I know of Hydrogen embrittlement is from my "sporty car" days where chrome roll bars were a NO-NO because the chroming process caused that problem.
And this guy fires it in a crowded football stadium!
Dave

[GGaskill]

Hydrogen embrittlement can be addressed by baking the plated parts at 400° F or so for a while.  The heat drives the hydrogen out of the crystal structure.

Cast iron is used for casting because it is much more fluid when melted than steel, which allows thinner sections and greater detail in the finished castings.  However, steel is cast, and the simple shapes of blackpowder artillery would seem to make them a candidate for steel castings.  Unfortunately, melting large quantities of steel is more difficult than melting large quantities of cast iron, so steel casting is more of an industrial process.

[Santa Dave]

Thank you sir!
Dave

[sixgun_symphony]

Scott,
It's only the cast iron and bronze tubes that require liners.  

 Did the originals from 200 years ago have steel liners?

 If not, then why do the modern reproductions require steel liners?

[jeeper1]

200 years ago surviving relatives didn't sue everybody.
Also I don't think steel had been invented yet. Steel making did not become practical until 1855 (Bessemer process).

[Double D]

Did the originals from 200 years ago have steel liners?

 If not, then why do the modern reproductions require steel liners?

Safety.  The originals were prone to bursting due to the less advanced metalurgy.  THe lliner give strength.

To replace eroded, corroded and wore out bores.

Safety.

[kappullen]

A horizontal machining center will make quick work of your mortar casting when ready.

The bore,  as well as trunnions can be machined in one setup with am indexing table.    A large ball mill can "profile" the id contour.

Cannons online in Maryland has their mortars done this way based on pictures on their website.

All you need is an 11,000 pound engine hoist to load it.

If I was serious about that scale,   I would sub out the boring operation.

Oh my aching back!  :cry:    

This shows the staking of a sleeve in a Confederate Mountain Howitzer.



Kap        :toast:

[kappullen]

Hern Iron Works now offers an 8" seige mortar and parts.

http://www.hernironworks.com/siegemortar.html

I have no connection with the above but it sure looks pretty!

kap