Brainstorming retirement project

[Double D]

I have this tube.  It has a 6 PDR bore.  I was going to build it as Confederate pattern Coehorn.



I have been thinking about building it instead to look like a U.S. 10 Inch Sea-Coast Mortar Model 1855



The cheeks on the original gun were cast iron.  For my gun the cheek would be 21" x 7" x 2 1/4".  I could  look around for some 2 1/4 scrap plate.  There is a company up in Alberta who makes reactor vessels and the uses plate this thick.  If I can find them I may be ale to buy some scrap from them.

Something I had thought about doing is making these cheeks by casting them myself.  Always wanted to learn foundry work.  Is  this something I could self teach myself?  If so where do I start.

[John Traveler]

Hi, DD!

I've browsed web sites that described backyard foundries that sand cast aluminum, bronze, and copper alloy objects, but have never seen anything that went into cast iron.

I suppose ANYTHING is possible, and if you happened to have a backyard coal mine, that cast iron foundry is possible too!

Good to see you looking forward to retirement projects.  Let us know your progress!

John

[Cat Whisperer]

I have this tube.  It has a 6 PDR bore.  I was going to build it as Confederate pattern Coehorn.
...
Something I had thought about doing is making these cheeks by casting them myself.  Always wanted to learn foundry work.  Is  this something I could self teach myself?  If so where do I start.

Nice cheeks.  (oops out of character for this board    )

Casting with which metal?  Aluminum would be most practical for strength and heat.  Bronze would be classy.  Ir'n would be histerically correct - yes; but you have to get it right-much hotter to cast.

How big a crucible would it take?

I assume from the shape/size that sand casting is in order.

Casting is scary the first time - tremendous temperatures, noise and heavy iron tools to hold the crucible with which one pours the melt.

Saftety equipment of special boots, leggings, aprons and gloves in addition to face protection.

Certainly a project worth the effort!

I'd start with a standard textbook on foundery practices.  Let me look through my collection to see if I've still got one.

[Max Caliber]

DD, One of the best books for the home metal caster in the United States Navy Foundry Manual. It is available from Budget Casting and Centaur Forge. Casting is fairly easy to do and one can make most of the equipment needed. I don't know why more people that are into building cannons don't take up casting. One should be able to put together the needed equipment to get started for around $300 if they are handy with tools and can make things like flasks, tongs, pouring shanks, etc.  Store bought casting equipment is expensive and is aimed more at those who do production casting. Using propane gas as a fuel makes casting easier and I have heard of people who do cast iron casting using it.

[GGaskill]

One thing to consider about foundry work is weight.  You would probably need to carry at least 100 lbs weight to pour one cheek in iron using a crucible and pouring shank, most of it at the end of the shank away from you. 

The mould I used to cast my bronze mountain howitzers (which are a little over 18" long) weighed at least 200 lbs.  The school foundry had an overhead crane that made it easy for us desk jockeys to lift heavy stuff but such a device adds immense cost and complexity to a home foundry.

Here is a short slide show showing an iron foundry in India making manhole covers for NYC.  Ignore the narrator's referring to the covers as "manholes."

As far as learning the process, there are several parts of the process, some of which can be done without the need to handle liquid metal.  Patterns need to be made and moulds need to be made before the liquid iron can be used.  If you can find a foundry, maybe you can learn that as an apprentice and then pour your moulds on "the company's time," paying for only the metal and related expenses.

While the tube you have should be more than adequate in strength, its wall thickness-to-bore ratio is noticeably less than an 1844 10" seacoast mortar (which is 8.75:10).  The muzzle wouldn't look quite right.

[seacoastartillery]

     Looks like a good one to make, DD.  Cupola furnaces are very cool when operating and the 10" size will crank out more cast iron in 10 minutes than you know what to do with!  Buy Steve Chastain's book on building one if you are VERY interested.  www.stephenchastain.com    Of course there are always the Lindsay Technical books and the CD by Stewart.  Mike and I saw one in operation in Connecticut two years ago and we were astounded that something that small could put out a continuous stream of molten iron!!

     However, if you want to have universal machinery left over after this project is complete, then consider factoring in a used Bridgeport Series 1 mill or clone thereof, and an engine lathe of 14 to 16" swing into your land purchase fund.  This is at least worthy of consideration and would be a much cleaner, safer and multi-use alternative.   Machining boiler plate available at almost all scrapyards in this 2.25-2.50" thickness would take about a day (to remove the waste material) and about 2-3 days to drill all holes and shape the outside edge.  FYI

Good luck,

Tracy and Mike

[Cat Whisperer]

AND another completely different alternative.  One which you might get some interest in on this board (including me).

a) make the PATERNS and

b) have a local foundary pour the iron.

c) repeat step 'b' for other folks!

[lance]

 Double D, that looks like an excellent project!!! I'll also mention Lindsay Technical Books, i have every foundry book they sell..........that's also one of the things i want to do, build a decent sized foundry. ya know me, always got to have something to play with     as a side note: i have a good friend that works at the Radford foundry,near where Tim lives.........anyway,he told me all kinds of things are snuck in there and cast without the company knowing anything at all about it

[Terry C.]

An alternative (one that I would pursue if it were me) would be to fab up the cheeks out of steel plates. They don't need to be solid.

A single plate equal to the thinnest section would serve as the framework of the cheek, with additional metal added where the cheek is thicker. Properly constructed, the end result should look like a solid unit.

Thinner plates would be easier to handle, and cut to shape.

[Cat Whisperer]

...
 i have a good friend that works at the Radford foundry,near where Tim lives.........anyway,he told me all kinds of things are snuck in there and cast without the company knowing anything at all about it

I'm SURE it could be done, but going through the front door would be repeatable. 

I'll bet that if we took our time at it, we could make a small 'production run' quite economically - especially if we made the pattern ourselves.  We could even 'rent out' the patterns to folks to make their own.

There used to be another foundary in Radford - many short run items came through there.  There is also an independant company that does nothing but make paterns for them.

Now you've got me thinking about making the side plates for my golf ball Dictator - (6" OD barrel).

[lance]

 Tim, i'll talk to my friend soon i hope, he is very hard to catch on a phone, but he lives in Willis as a side note: the same friend was at that other Radford foundry when it blew up, lucky to be alive.

[Double D]

While the tube you have should be more than adequate in strength, its wall thickness-to-bore ratio is noticeably less than an 1844 10" seacoast mortar (which is 8.75:10).  The muzzle wouldn't look quite right.

Actually George, you have touched on the hesitation factor I have on this project.   That is the bore to muzzle ratio is wrong.  The thought pattern is to finsh this tube out as originally planned in 6 PDR Confederate Coehorn.  While doing that acquire another piece steel and build a tube in pop can bore in the  1844 10" seacoast mortar pattern with the checks in iron or steel plate. Also while building the  6 PDR I can do some research on the foundry work, and see if I really want to get involved. 

The pop can bore rationale is that I seem to remember seeing various clubs hold pop can mortar shooting events using pop cans only and I don't have a pop can mortar..

I do have to set up a zinc smelting furnace also. 

I have a 12 inch swing lathe now.  I don't have a mill, do have access to one.  Finagling a mill into the land purchase would not be a safe idea.  Might have to do a couple of consulting jobs to cover that angle.

Man it starting to look like I'll never get sit in that rocking chair!!!

[GGaskill]

Now you've got me thinking about making the side plates for my golf ball Dictator

The mounts for the 1861 series of mortars appear to have all been made from rolled wrought iron rather than castings.

[Victor3]

 If I were to do it, I think I'd go with flame-cut plate. Home iron casting is an option I've looked into but for me, I don't think I'll ever be doing enough of it to justify the startup cost or storing the required stuff.

 If you can find a local place that does flame-cutting of large plate, make nice and look poor, you might just get a good price for what you want. They should already have a pile of plate chunks on site that would be able to be used for your project, so you won't have to pay any shipping or break your back delivering them.

[Cat Whisperer]

George you are histerically correct - built up side plates.  Remind me to get that 4140 off the floor of the truck into the mail box.

Victor - waterjet cutting is precise, looks good and COSTS too.

Lance - We need to persue this - there will be a time when several of us want something cast of steel (they do a quality steel casting - things like diferrential housings and manifolds.)

[Victor3]

George you are histerically correct - built up side plates.  Remind me to get that 4140 off the floor of the truck into the mail box.

Victor - waterjet cutting is precise, looks good and COSTS too.

Lance - We need to persue this - there will be a time when several of us want something cast of steel (they do a quality steel casting - things like diferrential housings and manifolds.)

Yes, but I was talking about flame-cutting, which is generally much cheaper than water-jet...

[accuratemike]

My vote is for flame cutting. But then, I am biased . I don't know about steel, but we had some thick plastics water jetted, and the edges ended up with some taper (like a plasma cutter would do). Flame (oxy/acetylene) leaves a nice, square, edge. Actually 21x7x2 1/4 would fit on my little, home-built, table. If I ever get around to it, I was going to flame cut the iron parts of the cheeks for the Gribeauval. Usually it is more time consuming to draw the item in CAD. I have software to convert a .dxf CAD file into g-code for the CNC torch. Good luck, looks like a fun project. MIKE


http://www.accuratepower.com/Torch
http://www.accuratepower.com/Rest

[lance]

Lance - We need to persue this - there will be a time when several of us want something cast of steel (they do a quality steel casting - things like diferrential housings and manifolds.)

Tim, i hear ya, persue it we will! i'm also serious about building a foundry we can play with, didn't buy all those books for the captivating bed time stories

[seacoastartillery]

     You guys are on the right track with the foundry operation, although the learning curve will be considerable.  If you want to make a pattern for the mortar pictured in the line drawing posted by DD, then you need to order the "10-Inch Seacoast Mortar, Model 1844" drawing from Antique Ordinance Publishers.  Actually, what you are getting is the 1840 Model, 10" Seacoast Mortar which evolved very quickly from the Model 1839, after only one '39 was built.  It's not a Model 1841, like Wikipedia claims, either.  There were 33 built from 1840 to 1861 and five survive today.  Wayne Stark wrote in The Big Guns, Civil War Siege, Seacoast and Naval Cannon that although Laidley identified the 10-inch seacoast mortar as a Model of 1844, neither a break in the registry number sequence, nor a significant weight difference exists among the 33 of this model produced.  All five survivors were produced by the West Point Foundry and Registry No. 2 was produced in 1842 which is really hard to do if you follow Laidley's I.D. (Model 1844)!.  The remainder of survivors,(4), were made in 1861, the last year of production for the Pattern 1840, 10" Seacoast Mortar. The Big Guns authors suspect the 1844 was a typographical error or scrivener, rather than a model change. 

     Anyway if you want to see one labeled correctly you can always go this link:  www.cwartillery.org/ve/mortar.html

     If you want to see the famous, historical photo of these guns being  emplaced at Butler's Crows Nest near Dutch Gap, Virginia, you can go to Wikipedia and do a search under "Siege Artillery in the Civil War".  Scroll down to the second main photo section labeled Siege Mortar Photo Gallery.  Look at those huge radiuses along the bottom edges.  Only casting will produce those without burning up     lots of end mills OR very fancy welding.  Dig those books out and buy one on Cupolas too.  Let us know when you are going to fire it up!  Hope you guys are on good terms with your neighbors; a ten inch Cupola Furnace can be heard from a mile away!  If you run one at night you will know what a volcano looks like close-up.   

Keep us posted!

Mike and Tracy

[Double D]

Square corner cutting ball end mill....

Horizon mill with a square corner cutting radius on the end...

I'll check E-bay...groan.

What a pain that would machine.  Artistic license would give it rounded corners.

Now to make the mould pattern for casting you could probably use some picture frame moulding.   

[GGaskill]

... but we had some thick plastics water jetted, and the edges ended up with some taper ...

All water jet cut material I have examined, no matter how thick, has had some draft angle to the jet cut edges.  It comes with the process.  In really thin stuff, it may not matter, but it's there none the less.

Remind me to get that 4140 off the floor of the truck into the mail box.

Remind me what I was going to do with that. 

[Cat Whisperer]

I think it had something to do with boring a hole in one end ...

[GGaskill]

I am thinking I was going to make a Rodman from it.

Only casting will produce those without burning up lots of end mills OR very fancy welding.

You mean the concave portion at the edges of the thick area where the trunnion rides?  Only need the ball end mill for the edge; do the rest of the area with square end mill or a shaper.

[seacoastartillery]

     George,  thank you very much, I just dropped my sandwich and ran out to the shop to check the length of stroke on our little shaper.  It's 6 inches, which is just barely long enough for the bottom edge radius and the vertical radius at the edge of the thicker area where the trunnion rides.  So, if casting is not possible, we may be in business after all.  We hate using ball end mills; they don't last very long and are so expensive.  Sometimes we tilt the head over at 20 to 45 deg. and cut a pseudo radius,(cove cut) if a true radius is not required.

     Thanks!!

     Tracy and Mike

[Double D]

Will the Cove cutting  or a shaper  make a square corner?

[seacoastartillery]

     Never have attempted that type of cut with the shaper, DD, but while the corner junction might not be possible to do only with the shaper, a brief use of a ball end mill could quickly finish this small area.  Because your standard end mill presents a tilted end surface at the junction, this method could not do it alone.  A ball would have to finish the small junction area if you used this cove cutting method.

     Good to have a fall back Plan B;  yes you could cut everything from solid plate.  Why all these exotic periphery cutting methods?  A good used bandsaw and a new bimetal blade can do all the cheek shaping cuts with little difficulty.  Low tech in this area is CERTAINLY cheaper and just as accurate if you use a little care.  Finish with files.  Fairly simple stuff.  FYI

Regards,

Tracy and Mike

[Double D]

Ah, files, now there is a language I understand!!   

[dominick]

accuratemike said:  My vote is for flame cutting. But then, I am biased  . I don't know about steel, but we had some thick plastics water jetted, and the edges ended up with some taper (like a plasma cutter would do).



Mike, With the newer water-jet machines, you can dial out the taper for a straight cut.  It's programed in the cut.  Dom

[accuratemike]

Dom, I'll bet that is pretty slick to watch. Nozzle tilting around as it goes about the part and all. I could watch CNC machines run all day. Well at least for a while anyway. MIKE