Mini Cannon

[lpeedin]

Neat, how much and what powder did you use? What is the bore ID? Bob

10-12 grains of FFg or FFFg black powder - BBs and pellets are .177 caliber - a #15 drill bit is .180 and works great. I got the fuse from cannonfuse.com - if I recall correctly, I used a 1/8" bit for that hole, but I'll need to double check that when I'm back in the shop. The breach end is drilled and tapped for 1/4 x 20. I did that to allow clean out in the event of a misfire.

Insert the fuse
Measure and pour in the powder charge
I use a small amount of cotton as a wad and tamp the powder and wad using a non-metallic ram rod (Q Tip with the cotton removed)
Insert the BB or pellet
Another small amount of cotton to hold the projectile in place.

These cannons are readily available via the internet - this is just my interpretation - and it's a lot more fun to build than buy.

 

[lpeedin]

I have seen some small ones made out of brass, but not alum. Although the size of this is not as big as the others I have seen. If you do decide to schetch up some drawings. I am very interested. (wife and animals might not be once done) what size charge are you using as that did look like a slot of sparks in your profile pic.
In the vid did it go all the way through the can or just the one side.

If you want a lot of sparks, as in a signal cannon, bore the barrel out larger. In the profile pix, that barrel was done with a 3/16" bit - .010 over. The fuse hole was oversize as well, but I don't recall right now exactly what I drilled that with. For a projectile cannon you want everything as tight as possible. You get more "bang" by compressing the powder and wad more, but you don't want to do that enough to prevent expulsion through the muzzle.

When I shot an empty can, it just knocked the can off the table. I put some water in the can and when I shot above the water level it went through both sides. In this video the pellet hit below the water line and it only penetrated one side. The MythBusters had a good episode on how fast water will stop a projectile.


SHOULD I EVER HAVE A MISFIRE, THE FIRST THING I'LL DO IS DROP THE WHOLE CANNON IN A BUCKET OF WATER and give the water plenty of time to soak the powder.

 

[lpeedin]

Here's a video where the projectile hit right at the fluid (beer) line. It went through both sides of the can.

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[lpeedin]

A couple of image captures from some videos. Note that the wheels of the carriage actually come off the table. In one pix you can see the cotton wad behind the pellet & in another you can see a tiny fire ball about 2/3 the way to the can.






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[lpeedin]

Some more pix I took in the shop. Forgot I had these.





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[lpeedin]

Do you see the mistake I made with the mill?

 

[T Bredehoft]

You mean where you took an extra corner of the step? That 's a witness mark.

 

[lpeedin]

You mean where you took an extra corner of the step? That 's a witness mark.

Yea, that's what it is.

 

[kvt]

Ok, a different monitor changes the whole thing. had my laptop hooked to a monitor at work all I could see of your pic was the sparks, Get home on my laptop and I see the whole thing. I can see the cannon in the picture as well. I see the miss step. What is the screw in the end of the barrel for.

 

[kvt]

Forgot to ask, Are the items on the sides of the cannon machined as part of the barrel or are they screwed on with the screws that hold it to the frame.