Thirty-odd years ago when I was in my teens and junior high schools still had wood and metal shops, my particular school hosted a weekly father- son shop on Tuesday nights. My dad is a talented engineer and mechanic and together we built a small non-firing naval cannon. It was about 12 inches long and we used the shop's foundry to cast the gun out of aluminum.
I have never forgotten that project and now that I'm a father (and a machinist) I thought it would be cool to make a cannon with my two boys. But, I thought, why not make a cannon that not only would actually fire but would fire something substantial? Why not make a cannon that would fire one pound lead balls? The die was cast.
I started with a 5 inch billet of 4140 twenty seven inches long. I had it rifle drilled and honed to a dimension ( I can't remember without going out to the garage and actually miking the I.D. what that dimension is at this moment.) that would accept a nominal one pound lead ball as cast from a dixie gun works mould. The bore is approximately 24 inches long.
I then cut sockets into the side walls about one quarter of an inch deep to accept the trunions. With this work behind me, I set out to profile the blank. I mounted the billet in the lathe and turned the cascable ( the rear ball) and the taper.
After the lathe work was complete I welded the trunions into the pre-machined sockets on the gun barrel. This was a little tricky because alloys such as 4140 (especially thicker material) must be pre-heated and allowed to cool slowly or the welds will crack. I heated the barrel with a torch to roughly 600 degrees, did my welding and buried the whole thing under a hill of oil absorbent (kitty litter). After more than twenty-four hours the assembly was still too hot to touch! How's that for slow cooling. No cracks, strong weld.
My boys and I began work on the carriage. We chose an approximation of a naval carriage simply because it is a little easier to build. It is made out of 1 3/4 oak (white, I think).
The project is almost complete. Only the finishing of the wood remains to be done and then we'll find a place to shoot.
One happy coincidence is that golf balls fit quite nicely into a bore designed around one pound lead balls.
I haven't the faintest idea of how to post an image or I'd do it. Too bad... looks cool.
Moderators note. Grumbly sent me an email message with photo's attached. It is so good that I am going to cut and paste it into this message and add the pictures...DDHello Double D:
That's a great idea! I'll attach a few photo's and you can feel free to post whichever you want or all if you want.
I'll give a brief explanation for each picture.
1. Right Side Cannon.
This is essentially the profile view. All visible acorn nuts are attached to allthread that runs through the entire length or width of the carriage components thereby drawing the assembly tightly together.
The wheels are pieces of 4" standard pipe faced to dimension and "filled" with solid maple. Gotta paint 'em; they look awful.
2. Rear View.
The rear view simply shows the overall width and proportion of the whole assembly. Also, the quoin (the apparatus that controls elevation) is visible in this view. A more traditional setup for the quoin would incorporate an integral dovetail rather than the slides that we installed.
3.Shop View.
This is a view of the cannon in my shop/garage which I included to provide a sense of scale.
4.Trunnions and Cap Irons.
This is a closer view of the trunnion and cap iron arrangement. The trunnions, as discussed earlier, are fitted into sockets milled about 1/4 to 3/8 deep into the sides of the barrel. The band that appears to encircle the barrel where the trunnions are located was material on the barrel that I decided not to cut away during the lathe turning phase. This decision was made to keep the trunnion sockets as deep as possible.
I used a little (very little) Bondo to feather out my welds in the interest of good looks.
The barrel itself weighs about 95 pounds.
The cap irons started out as two-inch steel plate flame cut to the general shape and milled to the proper dimensions.
Thanks again,
Heath (Grumbly)
