What to do with this thing?

[Victor3]

 Below are some pics of a cannon I built years ago  (In my late 20's, before the internet and shortly after the Gutenberg printing press came into use).

 I obviously didn't know much about cannons when I designed it. I was wanting a compact cannon with a large bore that was small enough to fit into a manageable crate along with everything required to use it. I based it roughly on pictures I had seen of seacoast guns.

 It became one of my 'cigar box' projects that never got off the ground. I just took it out of storage...



 The bbl assembly is four parts, all of 304 SS. The main tube is 3" OD seamless with a 2.28" bore, 14" deep. There is a threaded/welded plug in it. The outer chamber boot is 4" OD and heat-shrunk on with a .003" interference fit. The trunnion is one piece, held in a bore with a set screw at the rear. There is no powder chamber, so this bbl violates the accepted wall thickness requirement.

 The cheeks are 7075-T6 and are bolted onto a channel iron base. I put leveling/elevation screws in front...





 I made a fancy elevation device (never installed), as well as a slug mould that would allow me to experiment with different weights depending on how much lead was poured into it...





 After some time languishing in a box, I took it out and made a lock and vent insert to fire a 209 primer. I used a quick-release sling swivel so the lanyard could be easily removed...







 So..... What should I do with it now? I'd still kind of like to make something usable and safe out of it.

 I could:

 1. Bore a powder chamber into the breech plug (it's ~2" long). However, this would require plugging the existing vent, drilling a new one and junking the lock.

 2. Make a golf ball liner with integral powder chamber.

 3. Put it away for another decade or two and go paint the house.

 I've also considered adding wheels to it.

 Any input would be much appreciated...

[rifleshooter2]

I'd hate to see all that fine work go to waste. I'd make a liner for it and shoot golf balls, Just make sure you use a sub chamber. Besides painting the house is boring.

Andy

[Cat Whisperer]

If the choice is to do something minimal to get this project to the front lines and engaged, two things come to mind:

one, use it for blanks;

two, use it for golf-balls - which are MUCH lower pressure than with iron, zinc or lead projectiles.

[GGaskill]

The mount as it stands shouts "mortar" although it would be best to fire it with the barrel pointing the opposite direction from that shown and it will need a solid platform to keep from digging in. 

As far as safely firing it, you can do that as long as you don't use too heavy a shot and too much powder.  The breech wall thickness is about 7/8" from the numbers you gave which is below the forum recommendation but not insignificant.  If you can find or make zinc shot for it (you'll need a steel mould for that) and restrain the desire for bombarding the next county, it should be OK.

But a golfball liner would be even better.

[seacoastartillery]

     Victor3, from the traditionalists here at Seacoast Artillery Co., we have an idea that will enable a capable machinist like yourself to create a REALLY unique gun that will not only turn heads, but shoot as well.  This would involve more than a little work on your part, but we think the result would be worth it.  Starting with what you have now a 1/4 scale British Blakely Seacoast Gun is possible.  There is at least one in this country, privately owned, but photos exist and all the markings are known which is a huge advantage.  Made in the English city of Liverpool by Fawcett Preston& Co. in 1864, this seacoast gun, No. 95, has lines forward of the trunnions which you have almost perfectly duplicated in your posted pics.  The resemblance is incredible! 

     It's Sunday, our day off, so I will work on some sketches to SHOW you what the heck I'm talking about.  If you have a copy of The Big Guns, Civil War Siege, Seacoast, and Naval Cannon by Olmstead, Stark and Tucker you can see a photo of this gun on page 139, photo 10.9.  I will see about getting a scan, with proper credits applied, later as well.

Until later,

Tracy and Mike

[lance]

 Victor3, how about giving it to me, shipping paid of course oh, can you also send Mike and Tracy's drawings too

[phalanx]

I'm like Lance ,i sure know what i would do with it ,or i know some folks who would be thinking the same thing i am.
I'm not telling you to do this ,,,but,,, in what you have you have a great breech with step down.
Here in the oil fields they have a seamless tubing ,it has to withstand gas pressure of up 250,000 PSI and more.
Its OD is 2.250 ,its Id is 1.75 highly polished.
It is some kind of really strong SS , your tube is 14in deep ,cut some of this tubing 36in long ,Lathe its outside to a point it can be  super heated  on a  tube like this  ,freeze the tubing ,basically what was done on your chamber ,make sure it seats properly.
Then drill through what you have barely into the tubing and plug weld it.
Surface lathe the entire outside for effect.
Golf ball cannon.
I'm sure i started a flame here ,and i have never done it ,but i see a lot of Machine shops around here on a week end with a couple of guys using this stuff to make golf ball tubes.
I have seen them on the range ,i never heard of an issue.
One guy even took Off Shore high pressure Dill Collar casing ,4in od 2in id ,
Made a chamber tube out of 4in id ,6in od ,same stuff and he has a very nice gun.
Someone like Sea Coast could tell you better ,i am not saying do this ,but they can tell you better.
I would just make a real big noise maker out of it.
I am in no way a barrel maker ,i am only stating what i have seen done ,and i don't know which is stronger ,Laminated or solid.

[phalanx]

Speaking of barrels ,could someone tell me how standard cold roll ,bored milled ,plugged and welded stands up as a barrel ?
Surfing the web you always run across someone offering barrels made from this .
OK it is steel ,but is this material to soft to hold up as a barrel ?
Isn't it something only like a grade 5 bolt material ?
I know it bends easily ,scratches easily,and is easily cut or welded .   

[seacoastartillery]

    Victor3,   Take a look and let us know if this might be a possibility.  The top image is from The Big Guns by Olmstead, Stark and Tucker.  It is a large, British Seacoast Gun of the type used in the 1860s through the 1880s in England and her throughout her Empire.  The sketch is drawn to a 1/4 scale and also allows the slap hammer to be retained with a very slight modification to the tip.  The extra weight would allow heavier projectiles to be shot without uncontrollable recoil consequences to prevail.  All thickness rules would be met without a finicky chamber insertion operation.  We have drilled several slant vents;  you could easily do this with your experience.  Tap and then screw in a stainless vent-piece, and your all set.  A metal carriage could be designed and built to duplicate those in use in the Palmerston forts or you could go all-out and put it on a Montcrief disappearing carriage such as the one which can be found at Crownhill Fort today.

Let us know, Victor3.

Good luck,
Mike and Tracy

[Double D]

Cool!!!

[phalanx]

That is sort of what i thought it would look like. Much smaller scale , Going inward like that it doesn't give him a lot to play with.

[Victor3]

    Victor3,   Take a look and let us know if this might be a possibility.  The top image is from The Big Guns by Olmstead, Stark and Tucker.  It is a large, British Seacoast Gun of the type used in the 1860s through the 1880s in England and her throughout her Empire.  The sketch is drawn to a 1/4 scale and also allows the slap hammer to be retained with a very slight modification to the tip.  The extra weight would allow heavier projectiles to be shot without uncontrollable recoil consequences to prevail.  All thickness rules would be met without a finicky chamber insertion operation.  We have drilled several slant vents;  you could easily do this with your experience.  Tap and then screw in a stainless vent-piece, and your all set.  A metal carriage could be designed and built to duplicate those in use in the Palmerston forts or you could go all-out and put it on a Montcrief disappearing carriage such as the one which can be found at Crownhill Fort today.

Let us know, Victor3.

Good luck,
Mike and Tracy

 Mike/Tracy,

 That's an excellent idea. I hadn't even thought of adding another chamber piece - I had only considered  a bbl insert to go to a smaller bore. I appreciate your taking the time to post the picture and making the sketch for me. I have not seen many cannons (only mortars) having the trunnions back that far. I like the looks of it a lot.

 I have everything available to modify the bbl just as you show, and will certainly consider it when I can find the time to get this project going again.

 However, since I still have a 40" long piece of the 2.25" ID tube, I may just make up a Blakely breech for a new bbl. That might end up being easier than modifying my existing one. The breech would be a fairly simple item to make and heat-shrink onto my tube.

 Do you by chance have any pics of the "Palmerston fort" mounts?

 Thanks a lot guys. Certainly some food for thought for both my existing gun, and maybe a new one also!

 Regards,

 Victor

[Victor3]

Speaking of barrels ,could someone tell me how standard cold roll ,bored milled ,plugged and welded stands up as a barrel ?
Surfing the web you always run across someone offering barrels made from this .
OK it is steel ,but is this material to soft to hold up as a barrel ?
Isn't it something only like a grade 5 bolt material ?
I know it bends easily ,scratches easily,and is easily cut or welded .   

 Phalanx,

 Mild steel is probably the most common type of material used by hobby-cannon folks to make bbls from. Strength of most modern mild steels is better than some of the materials used for original period bbls. It holds up just fine and is safe to use for a properly designed and properly loaded bbl.

[GGaskill]

Speaking of barrels, could someone tell me how standard cold roll, bored milled, plugged and welded stands up as a barrel?

"Standard mild steels" are best referred to as 1018 (CR) and 1020 (HR) because all kinds of alloys are available as "cold rolled."  It also has the advantage of getting a particular alloy with known characteristics rather than some mystery metal that the steel seller has left over from some long forgotten purchase. 

I consider 1018 to be a superior steel for muzzle loading cannons when you are reproducing the proportions of antique pieces.  If you are trying to make a piece from the minimum amount of material (for least weight), then you should use the stronger alloy steels, after you have done all the engineering calculations that form the basis for original design.

[seacoastartillery]

     Victor3,   Mike and I agree with you, it's probably best to leave your unique cannon as is or maybe make just a minor change.  It's important, we believe, to have some "history" of what you have built.  Terry C. just posted the first entry in a new thread called, "the Official 'ones we don't talk about' thread....., which is an idea with lots of potential.  So, if you decide to craft a big British gun, fine; do it from scratch.  That method would probably yield more satisfactory results.  All the artillery drawings and photos you will ever need on the subject of British seacoast guns can be found at the link below posted by MikeR C just recently. 


http://www.palmerstonforts.org.uk/index.php


Regards,

Tracy and Mike

[dominick]

Victor,  That's a nice cannon you got there. Here's a method to determine safe loads for cannon barrels that are less than one caliber at the breech.  Whatever the thickness of the breech is, use that "bore size" amount in your powder measurement.  ie,  1" thick breech = 1" bore = 190 grains.  You can use the Switlik chart in the reference above to determine the proper amount.  The same can be done for projectiles.  The type and amount of powder, weight of the projectile, and its resistance in the barrel are what determines pressure and not the bore size. Whatever the weight of a 1" projectile is would be the maximum projectile weight.  As you can see, this method is precise and unforgiving, and does not allow for very thin walled cannons.  For example, a 1/4" breech wall cannon would have a maximum powder charge and projectile weight equal to 1/4" bore cannon.  Hope this helps.     Dom

[Double D]

If I read this right what Dom is sayings is to determine your maximum load by looking at the thickness of the breech wall.   

If you have a cannon with a 1 inch thick breech wall and say a 1 3/4 inch bore, to determine the max load treat this gun as if it has a 1 inch bore and use the load data  from Switlik for a 1 inch bore.

Then for the projectile for this cannon, what ever the maximum weight is for a 1 inch projectile that is the maximum weight 1 3/4 projectile to use.

Interesting.  I have never heard this before. Where did you find this Dom, this is very intersting!!! 

The only question I have is on the projectile  weight. Other than the N-SSA chart, I have never seen anything before on projectile weight for bore size. Composition and projectile shape are going to play a role in this.  Give us more, please this is very interesting

[Victor3]

Victor,  That's a nice cannon you got there. Here's a method to determine safe loads for cannon barrels that are less than one caliber at the breech.  Whatever the thickness of the breech is, use that "bore size" amount in your powder measurement.  ie,  1" thick breech = 1" bore = 190 grains.  You can use the Switlik chart in the reference above to determine the proper amount.  The same can be done for projectiles.  The type and amount of powder, weight of the projectile, and its resistance in the barrel are what determines pressure and not the bore size. Whatever the weight of a 1" projectile is would be the maximum projectile weight.  As you can see, this method is precise and unforgiving, and does not allow for very thin walled cannons.  For example, a 1/4" breech wall cannon would have a maximum powder charge and projectile weight equal to 1/4" bore cannon.  Hope this helps.     Dom

 That's excellent Dom. Sounds like a good way to stay well within safe limits.

 However, while I agree that this formula is "unforgiving", I wouldn't say that it's "precise" without taking the strength of the bbl material into account.

 Also, as DD noted, it should determined what the "maxmum projectile weight" for a given bore diameter would be. Maybe a pure lead ball with 1/40th windage in the case of a smoothbore?

 After looking at the design of my gun and taking material strength, projectile and charge weight into consideration, I believe I've come up with a safe way to shoot it nearly as is;

 Using a standard billiard ball (2.25" dia, 6 ounces) with a maximum charge of 200 grains FG.

 Does this sound reasonable to you guys?

 I may bore it slightly larger to add more windage than it currently would have with a billiard ball (it would have only .03" right now). I'll also have to add my elevation assembly and do a few other things to finish it. I may add some small wheels.

 One thing that I had not calculated until AFTER I built the gun was the tremendous recoil it would produce with a lead projectile ("Measure twice, cut once" came to mind at the time). I came up with ideas to add rear struts and steel plates to add weight, but then it would not have been the smallish gun I had intended originally. However, with a light projectile and charge, it shouldn't move too much.

 I was also thinking of using my mould for some type of epoxy or cement if I could find something suitable and cheap.

 Any thoughts?

[Double D]

Apply Dom's  theory to your barrel.  Your bore is 2.28 with an OD of 3 inches.  Wall thickness .36.  Standard load for a 2.28 in barrel 4.56 oz.     According to Switliks chart--well it doesn't go down that far but by extension .36 is about 30 grains.

Using his chart for a gun with a  1.5 bore  and 1.0 inch walls.  1.5 bore max load is 500 grains.  1.0 inch bore would be 180 grains.





 

 
 

[Terry C.]

Wouldn't the breechband be included in the calculations?

At the breech, the OD including the band is 4". This gives a total thickness of .86" at the chamber.



Charge weight for .86" would be about 130 grains.

[Double D]

Sure of course forget that. 

[dominick]

                                                              Doug, To answer your question, the general principle of breech wall, ball weight, powder charge has been around since at least the mid 16th century.  Here's the short version.  A Mathematician/artillerist named Luis Collado adopted a  system  were he divided cannon into three degrees of "fortification." Fortification was the term used to describe the thickness of the bore wall.  A gun thicker than one caliber measured at the vent was "double fortified",  one caliber thick was "legimate", and less than one caliber thick at the vent was inelegantly described as "bastard."  From a logistical view point, there was a need for lighter artillery pieces with thinner tubes.  Collado placed the emphasis on training the gunner to understand the different classes of guns.  Cannon burst in the batteries every day because the gunners were ignorant  of how the gun was made and what it was meant to do.  Most, but not all iron guns were one caliber thick or greater. Some bronze guns were made with thinner breech walls and the weight of the projectile and the powder charge in these guns were lessened .

                                                             Armstrong [not the 19th century Armstrong] and Muller in the 18th century followed this principle. Muller sought to increase the caliber of the cannon without  increasing weight.  Muller created a unit of measure by dividing the shot diameter into 24 parts.  The caliber of the gun was 25 parts or 25/24 of the shot diameter and the thickness of the barrel was expressed in the same way.  A typical field cannon was 16/24ths thick at the vent.  Emphasis was then placed on the powder charge and the shot weight.  Again, the exception to the rule was cast iron guns, which were typically one caliber thick at the breech.

                                                              There are three main conditions among others that can cause a cannon tube to fail.  1. excessive barrel pressure  2. metal fatigue  3. corrosion.  Metal fatigue is generally caused by excessive pressure.  Excessive pressure is the main area of concern when firing a lighter cannon and is caused in part by projectile weight and powder charge.  What I developed is a method of keeping the barrel pressure the same as if the gun were a one caliber thick gun.  Also, with the larger bore, the barrel pressure will drop off quicker when a projectile leaves the barrel due to the increased volume of the bore.  It's precise in that there is no guess work in measuring powder, ball weight, and grain size.

                                                              Now to the Victor's "double sleeved" cannon tube.  A cannon builder named Blakely in his writings, referred to a  mechanical engineer named Barlowe.  Barlowe found that the maximum strength in a tube was the inner portion of the tube.   As you move toward the outer wall of the tube away from the center, that portion of the tube does less for strength.  Another way to describe it is that  more metal does not mean more strength.  He found that there is a transition point in the thickness of the tube where you no longer add strength, just weight.   The higher the tensile strength of the tube the closer the transition point  to the inner wall of the tube.  By shrinking tubes over the inner tube, a gun barrel's strength was increased a good bit over what it would be if it were one solid piece of the same thickness.  This was  the advent of the modern "built-up guns" in use today.  Blakely, along with Treadwell, Parrot, Armstrong, Krupp and a few others, were original founders of this concept.   I hope this explains the general idea without too much confusion.   Dom
                       

[dominick]

Using a standard billiard ball (2.25" dia, 6 ounces) with a maximum charge of 200 grains FG.

 Does this sound reasonable to you guys?

 I may bore it slightly larger to add more windage than it currently would have with a billiard ball

 I don't work with stainless so I'm not sure what you have there.  I think the tensile strength of stainless is roughly equivalent to a grade #3 bolt.  I was told this by a bolt salesman several years ago, so I'm not sure if it's correct.
  If it were my gun, and this is only my opinion, I would start off with about 100 grains of powder and see what the ball does.  More powder does not necessarily mean higher velocity especially in a shorter barrel.  That big flame coming out of the front of the muzzle could be the extra 100 grains of powder burning up and doing nothing to propel the ball.  It's great for smoke and fire, but possibly a waste of powder when delivering a payload.  The windage is not a problem, providing the projectiles are consistent in size and the bore is of uniform diameter throughout it's length.  Dom

[Double D]

Only one  question reamians for m e.  How was maximum weight of projectile determined?

[Victor3]

 Great post Dom. I think I understand where you're coming from with your formula.

 I'm familiar with Barlow's formula for determining bursting pressure of tubes. I've used it in designing pressure vessels. The basic formula is:

 P = 2 St / D

 Where:

 P = Bursting pressure (psi)

 S = Tensile strength of tube material

 t = Wall thickness

 D = Outside diameter of tube

 The formula can also be rearranged to determine what is needed in terms of tensile strength or dimensions required for a given bursting pressure. Here's a useful link:

http://www.dixiepipe.com/barlows.html

 I believe that this formula must have been what was used by the early cannon designers along with other considerations.

 You appear to have distilled what was learned by our cannon-building forefathers down to a simple, safe, and useful formula. However, there are variables that if they were to be defined and considered, would make it more precise (But also more complex, and maybe less useful to some).

 In regards to "double sleeve" cannons, this might be an interesting read:

http://en.wikipedia.org/wiki/Hoop_stress

 Using Barlow's formula to determine bursting pressure on my bbl, it would contain ~40K psi at the breech.

 Dom, I'm very comfortable with the loading of a pool ball and 200 grains FG, but I will certainly take your advice and start out at 100 grains to see what it will do. You're right - no use in wasting powder.

[dominick]

                                                           Doug, I'm not sure if Collado or Muller had a written table or formula for determining maximum weight of a projectile.  I think the projectile itself determined the weight of the tube and the charge. That's why I used the phrase "general principle".  I do know that the weight of the projectile was a factor.  Both of these individuals wrote about it when explaining construction and use of artillery tubes.  I'm not saying that a formula does not exist.  I simply don't know if one does or not.  The closest I can find to it, is from Muller, who designed for example, the heavy garrison guns to have 172 lbs for every pound of shot, and ship guns weighed 146 lbs per pound of shot.  Also, there was a table for barrel thickness along the length of the tube measured at the vent, trunion and chase.   Length of barrels were 15 calibers for the ship guns and 18 caliber for the garrison guns.  He kept the powder charges at about one third of the weight of the projectile.  Collado varied the powder charges.  Full weight of the ball in powder for the double culverins, four-fifths for the legitimate and two-thirds for the bastard culverin.  It appears that everything was determined using weight as their unit of measure back then, hence the word "pounder" , 6 pounder, 12 pounder, 24 pounder etc.   

                                                           What I am saying is we are fairly certain from experience that a "properly constructed" one caliber thick cannon of the correct material can fire a lead projectile using  the Switlik chart, safely.  Then, by using the table of weights for lead projectiles at a given diameter, we can determine a safe maximum projectile weight for a cannon that is less than one caliber thick by using the thickness of the breech as the bore size.  With presenting this method, I am not advocating for the constructiion of  lightweight cannon and I also think that the one caliber thick rule for the Forum is a good rule and should certainly not be changed.   What I am proposing is, since there are so many cannon in use today as in the past, that are less than one caliber thick, here is a method of determining how to use them safely.   Dom

 

[dominick]

Victor,  Thanks for the website info. 

[Cat Whisperer]

Let me add the standard warning, the formula's are just a STARTING point.

The nature of the dynamic pressures of a cannon is different than that of hydraulics.

One MUST account for the repeated hammerings that a tube will encounter - that's not in the formula - it involves both good design and good choices of the type/nature of the materials involved.

If you're not a mechanical engineer or a metalurgical engineer you run the risk of missing that critical element that could get you killed.

Comparing your designs to those that have been proven over time with many applications by many people is simply prudent.

[Victor3]

 I agree completely, CW.

 I only posted Barlow's formula because it is similar to Dom's formula in that there is a relationship between wall thickness and a safe pressure/load that can be calculated. I didn't mean to imply that Barlow's (or any other single) formula is the only thing to be considered in a cannon barrel's design.

 I like Dom's formula in that it has a hefty built-in safety factor that limits projectile/charge weight for a given breech thickness (assuming a normally designed bbl).

 As Dom noted, there are many 'under-built' cannons out there that will be fired - Just like there are many Trapdoor Springfields that are used daily. One wouldn't want to use a full-zoot load in either gun, but they can both be fired safely if a safe load is able to be determined.

[Cat Whisperer]

Victor -

Some good comparisons!  I use my trap-door not daily, but with loads (lead bullets) designed for it's strength (or lack there-of)!