Not an engine---but what I did this summer

[awJCKDup]

Hi all, haven't posted in a while, but I wasn't completely idle this summer. I finished up a small cannon, from prints in an (I think) old popular mechanics magazine. Brass barrel, hickory carriage, made all the hardware except for the chain. 50 cal. Hope you enjoy the pics and video. The time stamp on the camera, needs to be reset!

It was an interesting project, since I didn't know much about cannons, so a little research brought me somewhat up to speed. Here's a link to a short poorly done video of it firing.



hope you enjoy
John

 

[robwilk]

;D Very nice work John . Are firing ball bearings out of the cannon

Rob......

 

[Omnimill]

Neat. How did you do the trunnions?

Vic.

 

[awJCKDup]

Neat. How did you do the trunnions?

Vic.

I Turned the trunnions separately with a short threaded stud, and turned a washer to use as the "shoulder". Tap the barrel and loctite.

 

[kustomkb]

That is beautifully made John.

It was hard to get a sense of scale until the video. Great detail!

I've often wondered, what is the clearance between the projectile and the bore?

Do you think the article might be found on google books?

Thanks,

 

[awJCKDup]

That is beautifully made John.

It was hard to get a sense of scale until the video. Great detail!

I've often wondered, what is the clearance between the projectile and the bore?

Do you think the article might be found on google books?

Thanks,

I think this is the link to the plans on google books
http://books.google.com/books?id=WC...ysburg how to construct a scale model&f=false

John

 

[kustomkb]

Thanks a lot John!

I was just looking and found this one also.

24 Pounder

Page 134.

Cheers!

 

[rake60]

Very Nice John!

Beautiful work on the details.
Where did you find the brass chain?

Rick

 

[awJCKDup]

Very Nice John!

Beautiful work on the details.
Where did you find the brass chain?

Rick

Since retiring, my wife and I have taken up going to auctions and yard sales, the chain on some costume jewelery was as close as I could find, thought about painting it but.... I think it looks good.
John

 

[Omnimill]

I've long been thinking of making a model Dahlgren shell gun like those fitted on the USS monitor but couldn't make up my mind what carriage to mount it on.

Vic.

 

[Swede]

Beautiful work! I especially like the iron rims and strap work on the carriage. Well done!

 

[Wrist Pin]

John
What kind of powder are you using to fire your cannon??

 

[awJCKDup]

John
What kind of powder are you using to fire your cannon??

I'm using 60 grains of Goex?? FF black powder, with no projectile, wadding only. That stuff burns D I R T Y !!!! pain in the @$$ to clean.

John

 

[Wrist Pin]

Thanks John
A friend found a signal cannon in an old house he bought. Long story short, I had to make parts to replace those lost and bored the cannon out to .501. Bought some black powder via the internet that had to be mixed from components. Never could get that cannon to make noise, just fizzle. My hunch is the powder I bought and assembled burned too slow be useful.

 

[Entropy455]

This is a picture of my cannon.

I built it before I purchased my 10-foot lathe, which is why the barrel has no taper.

The barrel is three-inch 1028 mild steel seamless tubing. The wheels came off an 18-wheeler. I cut the king-pin mounts off the spindles, machined them flush, and built a drop axle. The breach plug was welded up with 7018 rod, 100% penetration (about 15 pounds of rod). Even though 1028 is not considered susceptible to hydrogen embrittlement, I still preheated both the breach-plug and barrel to 250 degrees, to drive out any free hydrogen. The rod was baked for several hours at 500 degrees, to ensure that it was completely dry.

Helpful Tip: never use nitrocellulose based powders within a cannon (i.e. smokeless riffle powder). And never ever use nitrocellulose based powders that have nitroglycerine accelerators in them (i.e. smokeless shotgun and/or pistol powder). The pressure rises with nitrocellulose based powders are difficult to control, and just a few grams difference in charge could mean the difference between a “safe” shot, and over pressurization of the barrel. When you burn a charge of shotgun and/or pistol power within a cannon, the nitroglycerine accelerator can transition from combustion to detonation, causing roughly 4 million PSI - which will easily liquefy steel. I.E. don’t do it!

Pyrodex is relatively safe for blanks, but is not safe for firing projectiles. Again, the issue is controlling the pressure rise – a little too much Pyrodex is capable of building yielding pressures.

The only “safe” powder is REAL black powder. The bigger the cannon, the bigger the required powder grain. Do not use FFFF powder in anything but the smallest of model cannons – it will cause dangerous pressures. For my cannon, 1F is fine for blanks, however Cannon Grade (grains the size of oatmeal) is required for shooting projectiles – which is illegal to do by the way - with my cannon size. . . . . In the picture, I’m loading up a blank charge (two loaves of bread), with a charge of 1F black powder. The picture was taken on the fourth of July at our local gun range.

It weighs about 2000 pounds, and is road-towable.

 

[Wrist Pin]

Wow Entropy!! That must make a joyous noise!!!
The cannon I am working on would fit in your barrel with lots of room to spare! As a gun owner and re-loader, I am familiar with black and smokeless powders. And, as they are not substances to be trifled with, I did visit cannon and powder websites to research what I was asked to do with the signal cannon. Looks like FF black powder is the size to use. As I did this job in June of this year, I have forgotten what the charge size is but I did make a charge cup and told my friend not to exceed it in use.
The powder we bought on line just burns too slow. I tried using discs cut from cork to contain the gasses. That didn't work. I switched to wadded up newspaper. That didn't work. Best I got was a "PFFFFFST", lots of smoke and the wad fell on the ground. I think it is time to drive down to the corner gun shop, buy some commercial powder and try again.

 

[awJCKDup]

"PFFFFFST", lots of smoke and the wad fell on the ground------Yep, that's all I got when I used some Pyrodex that a friend gave me. That black powder worked great--------keep in mind I know NOTHING about what I am doing. I do know however, that black powder is a dirty, smelly way to shoot something, and hard to clean the cannon afterwards.
ENTROPY...Am I correct in assuming that when you tow your cannon, that you don't have any problems with tailgaters?
John

 

[Entropy455]

Sometimes I get strange looks while driving down the road. . . .

My cannon will rattle windows over a half-mile away!

My old cannon was much smaller (about 380 pounds), and I would use tee shirts as packing. The combustion event would consume over half the shirt, leaving the burning remains over 50 feet away. I found that if I wetted the shirt down first, I would only burn about 10 percent per shot, and the shirt would not burn on the ground afterwards. I could pick up the scraps, and reuse them.

With my big cannon however - I loaded full size beach towel (wet) and the biggest piece I found after the shot was about one inch long, and a half-inch wide. Needless to say, cloth was no longer an option. I found that bread makes for excellent cannon packing. It’s moist, packs well, doesn’t burn, it’s biodegradable, and nothing but crumbs are left over.

The purpose of the packing is to give the charge a “little something” to push against. It will reduce the required charge for a given bang. You should also be able to fire a pure blank charge (powder only) and get a nice bang. If you’re getting a fizzle, then your grain size is too large – reduce it. Or your charge size is too small - increase it. For miniature cannons (firing blanks) you might need to use FFFF powder. There are even finer pyrotechnic grades of black powder (for fuse making I believe), that are available. A mini cannon will require very small powder grains. On that note - loading FFFF powder into a big cannon would be a serious mistake.

Do not use a blank-charge quantity of powder for firing projectiles. A projectile will require 1/2 to 1/4 the amount of a blank charge, to achieve very high combustion pressures. A blank-charge will a projectile is likely to over pressurize the barrel. Projectile loads are smaller, with larger grain sizes.

I normally wrap my charge in aluminum foil. It keeps the bread and/or shirt out of the powder, and also stray firework sparks out of your powder. Probably the most dangerous thing you will ever do in life is pour black powder out of a 1-pound can, when other people around you are lighting off fireworks. So don’t do it. Weigh and wrap your charges the night before. I use a pice of 1/8" welding rod to poke a hole into the foil, so that the fuse makes direct contact with the powder. In the old days, cloth bags were used for the powder charge. Needless to say, if burning cloth embers remained in the barrel during reloading, the gunner would be disemboweled. (Aluminum foil is MUCH safer)

Also – plastic is a no-no. Black powder is easily ignited by static electricity – which is why the product is normally sold in metal cans, or from specially engineered static-free plastic containers. NEVER pour black powder into a plastic bag, or any type of plastic container – or you’re asking for serious skin burns.

You do not need to “pack” the powder charge. Use a WOODEN rod to squish the foil ball down, so there are no large air pockets between the charge and your wadding. An air pocket will cause rapid expansion of the charge, followed by an impulse event (I.E. a pressure spike). So get off of the air out of the charge, but don’t pack it. You can however pack the bread. . . .

 

[Wrist Pin]

Thanks Entropy
Lots of good info in your post. I hadn't thought of using bread. (Using bread is good if you have to solder a copper water pipe leak. The bread keeps the water away from where you are soldering, absorbs any water trying to get to the solder site and blows out the faucet when you are done...but I digress).

I am going to get the cannon back and give it another try. I haven't had to post a picture here yet so if I can figure out how, I will post a picture of what I have.
Jim

 

[awJCKDup]

Jim, the advice I was given when firing a unknown/untried cannon for the first time, was to start with a much smaller charge than what I thought the final charge would be, and work your way up in small increments. I had also found a list for small cannon safety, can't remember where I found it, maybe Dixie Gun Works? There were things I hadn't thought of like "swab the barrel with a damp mop to make sure there are no hot embers which could ignite the next charge you put in" and many others. It would probably be a good idea to find those if you can. Always best to be safe!!

Good luck
John