Buddy of mine wants to build a cannon

Discussion in 'Blackpowder & Musket' started by Scratchammo, Apr 18, 2012.

  1. Scratchammo

    Scratchammo New Member

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    So a buddy of mine wants to build a black powder cannon with 4130 chromoly cold rolled steel tubing measured at 18" long, 1" in caliber, & a 1/4" wall. He said he wants to replicate loads similar to that of a swivel gun but he said he's not stupid enough to hold it. He wants to use a solid round ball & ffg pyrodex. How many grains should can that tube handle safely?
     
  2. hiwall

    hiwall Active Member

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    How are you plugging the end of the tube? That is the area of most concern. Cannon builders frown on welded on ends.
     

  3. Ranger-6

    Ranger-6 New Member

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    Your friend might want to check FFL regulation.
     
  4. purehavoc

    purehavoc New Member

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    Out of personal experience I dont think 1/4" wall thickness it heavy enough for that kind of load shooting a projectile .
    My uncle has one he build its more like 3/8" thickness about 18" long , we load it up jab newpaper in it and pack that ol girl tight with a 1" oak dowel and rubber mallet , stand back 20 or so ft and pull the drop cord . KAAAAABBBOOOOMMMMM it has 3 legs about 8" long with 2" flat circle bases . you should see what it does to a truck bed when it goes off back there . 3 real nice perfect circles about 1/8" deep . We make sure its on the ground when it goes off now :)
     
  5. Scratchammo

    Scratchammo New Member

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    He's gonna have it threaded for a 1" screw plug.
     
  6. Scratchammo

    Scratchammo New Member

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    I looked around & couldn't find any FFL regs for cannons using black powder.
     
  7. c3shooter

    c3shooter Administrator Staff Member

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    4130 is a decent material- it is used for modern rifle barrels.

    As indicated, the issue is not so much the material itself, but how the breechplug will be held in place- and welding is not generally a good idea. Also, consider how the trunnions are attached- you do not want to be changing the heat treatment of the steel.

    If it uses loose powder and ball, and does not use modern primers, ATF does not care- it is not a firearm (it is an antique- even if you made it today)

    The load will not be as critical as you might think- what does not get burned in a black powder barrel gets blown out as unburned powder. So long as you use black powder (or a BP substitute) and the projectile is FIRMLY AGAINST THE CHARGE- it would be hard to burst a barrel.

    I made one cannon as a present for a friend (hey, he bought a boat- needed something to repel pirates, OK?) THAT one started as a 3 inch rod of bronze, 4 inch length over chamber left full sized, then tapered down to 1.5 inch OD barrel, smooth bored to 0.75 inches.

    Proof fired that with 200 grains of ffG, and a 1 oz lead slug. Had touchhole, used cannon fuse (a LONG length of fuse!) 4 proof shots, no changes in exterior dimensions. He mainly uses it as signal gun, 75 gr ffG, paper wadding.

    BTW, these folks are firing BOWLING BALLS using cut off oxygen tanks. Those are made out of (I think) 30 CrMo, have a wall thickness about 5.7-6mm.

    [ame]http://www.youtube.com/watch?v=dIMNdobqUH8[/ame]
     
  8. Scratchammo

    Scratchammo New Member

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    Noted. I guess we'll have to start with small charges & measure for chamber expansion along the way.
     
  9. Scratchammo

    Scratchammo New Member

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    HOLY CRAP!!! I need that :eek:

    Yep, it'll be loose powder & ball (or other stuff). I talked him out of welding a plug. I'll have to post videos of this thing once it's completed.
     
  10. W. C. Quantrill

    W. C. Quantrill New Member

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    There are numerous articles on building and firing cannons on the searches. The rule of thumb on cast cannons was that the barrel was as thick as the bore. Everything about a cannon is in relationship to the bore diameter. Even the wheels are functions of bore diameter. There are also some books available that give specs on the cannons.

    I suggest that you all get into a bunch more research before you do this. The info is online.

    The amount of powder is also a function of the weight of the ball. Too much or too little and you can get some really high pressures. Go to the cannon pages where they shoot the cannons and talk to those guys.

    I saw one cannon that had the breech plug threaded in like a black powder rifle, It should be threaded in at least as far as the diameter of the bore, then it could be welded by a certified pressure vessel welder who would heat it to 600 degrees and then weld it, then pack it in ashes and let it cool very slowly to preserve the integrity of the weld.
     
    Last edited: Jul 7, 2012
  11. HockaLouis

    HockaLouis New Member

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    The rule of thumb for cast wall thickness is 50% of the bore I believe. But that's not steel.

    I chose to buy professionaly reproduced fully-cast steel-lined bronze and cast iron for my both my 18th C. Cohoern mortar and swivel cannon, respectively, for safety's sake. All it takes is one accident...
     
    Last edited: Jul 7, 2012
  12. W. C. Quantrill

    W. C. Quantrill New Member

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    My scale Carronade is a 1.6" bore with a 1.25" wall thickness at the muzzle, and 2.25" at the breech. It was cast for me by John Hern of Hern Iron works at CdL, Idaho. I had him cast in a high pressure seamless steel bore liner. It will punch holes through car bodies at 1/4 mile with an appropriate lead ball and powder charge.

    I chose not to turn my own barrel, although I could have.

    [​IMG]

    Barrel on my deck, 2x6's. for size reference. Weighs right at 100 pounds.
     
    Last edited: Jul 7, 2012
  13. Scratchammo

    Scratchammo New Member

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    Nice piece!
     
  14. W. C. Quantrill

    W. C. Quantrill New Member

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    I strongly advise obtaining a copy of this book. It is the bible on cannons.
    [​IMG]
    Your friend should obtain this book and study it before getting into the sport. It contains 300 pages of detailed information, charts, graphs, drawings and dimensions of about every known type of cannon.
    [​IMG]
    This is but one of a number of pages with comparisons of guns and loads.

    [​IMG]
    Some details concerning charges.

    Before I had John Hern cast my barrel, I contacted Mr. Tucker while he was at TCU, and we visited with him several times before I obtained my cannon. Mr. Tucker is an authority on cannons, and has 3 books out on them. There are several companies with cannons for sale. It might be worth your time to contact them about clubs that shoot cannons in your area, and get involved with them. Another thing to note is that the pressure in the barrel increases substantially as the angle of the barrel is elevated.
     
  15. St8LineGunsmith

    St8LineGunsmith New Member

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    I have seen a lot of misinformation about building cannons here.

    There are no regs preventing anyone from building a muzzleloading black powder cannon
    .
    a cannon with a 1" bore needs to have a minimum 3/8" wall thickness using 1018 or 1026 mild steel DOM but if you are using 4140 or 4150 Chromalloy you can get away with using 1/4" wall thickness as long as you dont go over board on the powder charge.
    175 gn charge should be safe but I would proof test it with at least 250 gn charge to make sure it is going to be safe to shoot.

    Most cannon breech plugs like an 8 pound mountain howitzer are shrink fitted then welded.
    with a small bore cannon such as the one your friend wants to build you can thread the end of the barrel and use a threaded breech plug.
     
  16. Scratchammo

    Scratchammo New Member

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    Good info. Maybe I need to check those out.
     
  17. Scratchammo

    Scratchammo New Member

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    Wow, 175 grains would pack a punch! Hell, it might even be a good punt gun lol.
     
  18. HockaLouis

    HockaLouis New Member

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    Amazing. Yeah, that poor cannon, having to somehow cope with firing quite less than double a standard musket charge.
    :rolleyes:
     
  19. St8LineGunsmith

    St8LineGunsmith New Member

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    you want to use more powder use thicker barrel material.
    get some 1/2 thick 1026 DOM you couldn't blow that up if you tried
     
  20. griffin81

    griffin81 New Member

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    I've seen bowling ball cannons made out of welding gas bottles they work well!