My First Pneumatic Cannon

[MarkV]

Gippeto,

Thank you for clarifying your concerns. I'll see if I can find a hose clamp to tie the barrel to the air chmber.

I'll look into the chamber sealing piston valve for my next gun.


Ed,

The wheels are from Harbor Freight Tools and cost about $30 each. They are VERY cheaply made though and required a bit of work - and they are still weak.

1. Get a store employee to open all of the boxes so you can sort through them and get the best pair. Look for a good circular shape, minimal cracks and knots, well centered hub, and no flexing.

2. Remove the metal bands around the wheels. These bands were quite loose on my wheels and didn't contribute to the strength of the wheel at all - but they did cover cracks that needed to be glued and got in the way of painting.

3. Squirt wood glue into all of the joints, knots, and cracks in the wheels. Note that the spokes are STAPLED in, rather than being let into the rim boards as they should be. I am counting on the wood glue to really hold the wheels together. Let the glue dry before proceding.

4. Insert a metal bushing into each wheel hub. The bushing should fit snug into the wooden hub and have the inner diameter needed to turn easily on your axel. I simply cut a piece of metal tubing to fit and hammered it in, making sure that the back of the hub was supported while I hammered. (Be careful, if the bushing fits into the wheel hub too tightly, your hammering will split the wood.)

5. Prime and paint the wheels.

6. Don't expect the wheels to last five minutes if you treat them like real wheels. I consider them to be just a stationary support for my cannon. When I move it around, I carry it rather than trust the wheels.

If you are willing to spend about $250 you can have actual wheels made to spec here: http://www.cannonthunder.com/index.html (I have no ties to the seller and have never ordered from him.)

MarkV

[starman]

This would also give me a place to put a stiff wire, sticking out of the face of the plug, that could keep the ball from rolling back over the hole. - What do you think?
MarkV

First off, excellent gun!! There are obviously many hours of study and consideration put in to it. In my view, while not the most powerful, overall one of the upper tier pneumatic designs on the site.

My first concern drifted to how you were going to consistantly get the ball out in front of the air tee. I think your plug idea will work just fine although I would use a small bolt instead of a wire on the plug face.

I have successfully used the barrel dimple method where you tap and screw hole into the sched 80 barrel sleeve but not the SDR21. Then you twist a small screw into the tapped hole, tightening just enough to press a dimple into the SDR21 deforming it slightly at the place you want to detain the golfball. You can also install a dimple in front of the ball location to keep it from rolling out the front.

Again, beautiful project.