Mini Cannon Fires Away!

mini cannon

Mini cannon fires!

A friend of mine named Foster recently gave me this great little mini cannon he made from our material as a gift. It uses actual black powder and fires a small lead BB. We decided a test firing was in order! Foster designed it to fire in my apartment without making the neighbors nervous. But still, we decided firing off a small cannon in the office probably wasn’t the best idea. So we headed down to an empty park, set up the target, and put a couple mini cannon balls into it.

Simple construction

Materials

The mini cannon consists of five pieces.

  1. 1x 1″ dia x 2.5″ 304 stainless steel round bar – for the cannon
  2. 1x 1″ x 1″ x .25″ x 2.25″ hot roll angle – for the carriage
  3.  1x threaded steel bolt
  4. 2x washers
  5. 1x steel nut

Steps

Use a drill press for this if you have one. You will be more accurate and the barrel will be straighter. Also, Foster got the bar a little oversized and machined it down to exactly 2.5″ long.

Machining

  1. Drill the main barrel, a shaft 1.5″ long smack in the middle of the bar. Make sure the barrel is slightly larger than the BBs you want to use.
  2. Drill the vent, a small hole at the end of the barrel, 1.5″ back. This is the trickiest part because you need to drill just enough that the vent connects with the barrel but you don’t accidentally drill a divot into the other side of the barrel. Also, the vent must be smaller than the barrel. Excess gasses will escape from there, and the larger the vent, the less efficient the mini cannon will be.
  3. Make the pivot hole. The pivot attaches the mini cannon to the carriage. It also allows you to aim up or down. To make the pivot, drill another hole completely through the cannon about .5″ from the back. Line it up to be perpendicular to the vent. This makes sure that the vent will be facing up once the cannon is mounted. Drill a matching hole in one leg of the angle, about .75″ from the edge and top. The hole must be the same size as the bolt. You want to allow the cannon to pivot but not be loose or rattle.

Assembly

  1. Place the bolt through the pivot hole in the angle.
  2. Slot on a washer.
  3. Slot the cannon onto the bolt, make sure the vent is facing up.
  4. Place another washer and put on the nut.

Boom! Now your cannon is ready to fire. Loosen the pivot nut to aim up or down then tighten it again when you’re happy.

mini cannon

A side view cut-away of the angle (left) and cannon (right) for illustrative purposes. Not to scale.

 

mini cannon

Foster rounded and tapered the edges on the angle, but that’s entirely for style. The muzzle is slightly tapered as well, which makes loading easier. And the little wooden powder scoop doubles as the ram rod for the ball.

Loading and firing

Here’s a bit of trivia for you. During the 18th and 19th centuries, the five-man cannon crews in the British army were assigned a number between 1 and 5. Their number told them what they were supposed to do during the loading process and in what order. This is where the phrase “do this by the numbers” originates from!

The first step of loading this mini cannon is to put a small amount of gunpowder down the barrel. We are talking about a little more than half the size of the nail on your pinkie finger sized.

Next, put the ball into the barrel and use a ramrod to shove it all the way to the back. Use something made from wood, padded, or that won’t ever risk making sparks when it slides along the barrel.

Then, prime the vent for firing. Originally, my mini cannon was supposed to have a fuse. But the ones Foster ordered wound up being too large to fit into the vent. So instead I just piled a little extra black powder on top of the vent to fill it and lit that.

Now you’re ready to aim and fire! Ignite the fuse/powder at the vent to fire. If the vent fizzes but doesn’t go off, wait a minute and try again. Do NOT LOOK DOWN THE BARREL if it fails to fire.

Safety notes

It goes without saying that any time you are dealing with black powder or projectiles, some risk is involved. Therefore, don’t aim at people, animals, or anything you don’t want to risk breaking. Again, NEVER LOOK DOWN THE BARREL. This is especially true if the cannon is loaded. You’ll shoot your eye out, kid!

After you’ve fired, wait a minute or so before loading it again. There is a slight chance that there may be some powder embers still in the back. If that is the case and you try to load more powder, it will go off prematurely. On a cannon this size that’s less of a concern than with full sized ones. But still, safety first!

Lastly, black powder devices are mechanically inefficient. When you fire, you’ll notice a lot of smoke and unburned powder shoots out of the barrel and also out of the vent. As such, don’t lean over the vent when firing. You’ll catch grit and that unburned powder in your face. Trust me, I’ve done it before and it’s no fun. On that note, eye protection is always a good idea.

mini cannon

You can clearly see what I’m talking about on this larger cannon.

With all of this in mind, be safe and have fun! If you make a cannon of your own, or even just part of one, please send us pictures. We want to see!