View Full Version : A cannon I machined from 5" diameter stock

08-07-2011, 09:43 AM

This is a cannon I machined from 5" diameter manganese bronze stock. It was the retirement gift for my original director at Colonial Williamsburg,Earl Soles,who hired me in 1970.

It has a bore of 1 3/8" to shoot forged ball bearing balls that Jon,my journeyman,and I found barrels full of at the scrap yard. We bought hundreds of pounds of them.

To bore out the barrel,I took a regular taper shank drill and welded a long 1" shank onto it. Then,with a tool post grinder,I took a light grind off the diameter of the drill as it rotated in the lathe. The drill drilled the bore as smooth as a cylinder in an automobile engine. Scratches in bores mean that the drill has a curve in it.

This bronze looks the same color as the piece of 4'x8'x1/2" thick plate that I am getting ready to saw up . It was similar to cutting stainless steel.

The gun is modeled after the long Toms aboard the USS Constitution.

The carriage is mahogany.
In person,the bronze has a darker,richer gold color.

08-07-2011, 09:48 AM
Very nice looking piece of work

08-07-2011, 10:23 AM

08-07-2011, 10:42 AM
Nice work, but to me the obvious question is have you fired many of the balls you bought, and if so, how well does it work? Range? How much do the balls weigh and how much powder for the charge?

08-07-2011, 10:43 AM
Very nice!
How are the Trunnions attached to the barrel?

08-07-2011, 11:00 AM
They are threaded in with a nearly interference fit thread. They go into counterbores,where the trunnions neck down some and become threaded. I fitted them so that the threaded portions bottom out against each other just as the trunnions bottom out against the counterbored. Loctite used for the final assembly. I made a special wrench that fit round the trunnions,and used paper and rosin powder to grip them good and tight. Wrench was tightened with a large allen bolt. Then,the gun was bored out.

Black powder explodes all at once in the breech. The trunnions are away from the breech. The gun has not blown up! I don't have it here. It was a retirement gift to my boss.

I have seen an original 18th.C. pistol with a barrel made of solid sterling silver. The builder fitted an iron tube about 2" or 3" long to take the instant blast of the black powder. The bore of the iron tube was the same as the bore of the pistol,and the breech plug was threaded into it. This short tube was enough to keep the silver barrel from blowing up. It had to be proofed before it could be sold.

The cannon is eminently strong also,because it is made of cold rolled bronze.

The cast brass they used on the original guns was no where near as strong.

08-07-2011, 11:16 AM
Have you met Henry Szostek of the New England Model Engineering Society? Henry is a cannon builder too. He lives near Boston, and for his model of a USS Constitution cannon he was able to get some scraps of the live oak timber being used to restore the ship to make the carriage from. Not quite "wood taken from the USS Constitution," but it is "wood going into the USS Constitution."

If you go to the Cabin Fever model engineering show in January in York, PA, look him up and talk cannon building. He's hard to miss -- he's 6'9" tall. He should be at the NEMES table.

08-07-2011, 11:46 AM
They are threaded in with a nearly interference fit thread. They go into counterbores,where the trunnions neck down some and become threaded. I fitted them so that the threaded portions bottom out against each other just as ....

..... The trunnions are away from the breech. ....

Wait George, I don't get it.

Ref your comment: "...I fitted them so that the threaded portions bottom out against each other .... "

Are you saying the trunnions go all the way through the bore?
Or does the bore stop short of where the trunnions are positioned?

The powder charge isn't placed rearward of trunnions protruding through the bore is it?

08-07-2011, 12:50 PM
From his description, he made the trunnions as close as possible to being a solid piece of the cannon, then bored THROUGH the threaded sections to create the barrel.


08-07-2011, 01:34 PM
Yes,danlb,I bored clear through the cannon when it was still a straight 5" bar. Then,threaded the hole. Then,I counterbored each side just deep enough that when the cannon was turned down to size,the trunnions on the bottom of the barrel would JUST be buried in the counterbore.I put a little high spot blue on the ends of the threaded portions of the trunnions,and a little blue on the bottoms of the counterbore. Then,I faced off the trunnions' ends,until the hi spot blue got crushed both in the bottoms of the counterbores,and on the ends of the threads.

Then,the cannon was bored. There was no gap at all where the bore went through the trunnions.

I hope this makes sense.

08-07-2011, 02:29 PM
OK, I think I got it now.

08-07-2011, 06:39 PM
Another interesting well done project, thanks for the great pics of your'e projects!!

08-08-2011, 09:09 AM
Thanks for the kind comments,guys.

Your Old Dog
08-08-2011, 02:10 PM
Very nice! Your boss should be thrilled with that. He doesn't live in the city does he? :D

08-08-2011, 04:35 PM
That is VERY nice work George. I have a couple of questions-NOT critcisms. First what is a "long tom?" Did you work from plans, and if so, where did you get them?
I assume that towards the end of the eighteenth century, a bit of a cannon industry was developing in your country, and that designs were evolving. FWIW, Mueller, Master of Ordinace for Britain, recommended mounting trunnions on the centerline of cannon in 1752. However, since NOTHING ever changes, the Navy paid absolutely no attention to the Army, and it was a while before the idea was adopted.
What windage did you allow? Again, Mueller, in his book "A Treatise on Artillery," stated that the British used 1/20 calibre while the French used 1/28. He proposed 1/24 as a reasonable compromise that could STILL handle rusty balls and yet improved both range and accuracy while diminishing wear.
Finally, what charge does this model take? Again, in theory, a working charge for a naval cannon would be 1/3 of the weight of the ball. I suspect that such a charge would create quite a recoil as well as surprise the neighbors!

08-08-2011, 09:28 PM
Duffy,a long Tom is a nickname that was given to the extra long cannon used on the main gundeck of the USS Constitution.

The Mariner's Museum in Newport News,Va. used to sell the plans,but they don't now. I think you can get them from the USS Constitution's museum.

I don't know what Earl shoots out of his cannon. He lives a good distance away. I haven't made the carriage for mine yet,but as mentioned,we have these 1 3/8" ball bearing forgings. I made a good knife out of one of them.

I have a 1" cannon of the same model,I turned from steel,made some time ago that is longer in proportion than this gun. I had to use the length of bronze I could get,of course,and was lucky to get it as scrap. This piece of bronze would be very expensive if bought new!

I have shot 1" ball bearing balls out of the steel cannon,and as much as 400 grains of powder. It makes a tremendous blast when it goes off. I could take a picture of it,but with the black barrel,it isn't as nice as the polished bronze,but definitely indestructible! It has a Walnut carriage. Sits on top of the wood stove in front of the fireplace.

We only have about 100 yards of range to safely shoot into a ravine,so range is pretty much point blank. I would not want stray balls bouncing off to who knows where!!

08-08-2011, 09:29 PM

I need to get off my butt and finish mine.

andy b.

08-08-2011, 10:54 PM
Reminds me of my fraternity days. There was a house with a small cannon whose bore was a perfect pool ball fit, and they would get lickered up and take pot shots at a neighboring campus 1/2 mile away. The university eventually plugged the muzzle with cement.

08-08-2011, 11:24 PM
Lucky nobody got killed!!!

In Colonial Williamsburg's earlier days,a lot of stuff went on that would not be tolerated today. At the powder magazine,there is an octagonal high brick wall surrounding the octagonal magazine. Now,you had young guys with a lot of black powder and cannons to play with!!:):):)

One of their favorite things to do was to load up a cannon with a tennis ball,and fire it horizontally around inside the brick wall! Needless to say,you had a high velocity tennis ball slamming around and around inside the wall. Lucky no body got smacked with that,either.

Another thing they did was to occasionally send an apple flying off in the direction of the Williamsburg lodge. No telling where those landed.

One last feat was to put a bunch of black powder in a wide copper pan and light it off. There would be a bunch of tourists getting a lecture on military history in the walkway above. They would suddenly find themselves enveloped in a large cloud of sulfur laden smoke!! That would get them fired in a hurry today.

08-08-2011, 11:44 PM
I just showed that picture to my wife and her comment was "Ohh... Sweet!". I'll point out that she is qualified and licensed for long guns and hand guns... but not cannons. ;)

08-09-2011, 10:31 AM
Well,the new cannon is going into the living room beside the fireplace whenever I get the carriage done. On top of the wood burning stove in front of the fireplace is a smaller edition of the same gun.

J S Machine
08-09-2011, 11:16 AM
Very nice work