Those parts look super clean. Nicely done! Smooth as a baby's arse.

That is sweet!

Those parts look beautiful. I was wondering about the shape of the piston as well. Seems air would go by it. What kind of cannon is this for? As for 3D printing, I've been tempted to get into it myself to make interesting projectiles. I have ideas to 3D print camera holders to shoot from the cannon ...

That is an interesting problem I've not encountered. The things you learn through experience...

^ I'm just curious to know what would really happen. Maybe one cannon fails like you'd expect, but a duplicate cannon fails in a totally different way. The only way to really *know* is to destroy not just one, but several of them at least. Repeated testing to failure is necessary to satisfy my desir...

If I had the money, I'd make 3 of every cannon I have and test two to failure under different conditions. That way I'd really know the safety factor in a practical way and discover the weak spots and failure mode. Unfortunately, you could buy a nice car for what all that would cost, so it is what it...

Disaster averted? Also, you need to know the yield strength to make a calculation. Without knowing the grade of steel, assume it's the weakest stainless in existence, plus the weld seam.

Watch out with that. I'm thinking your tube might have a weld seam since it's just a structural steel tube, right? Only seamless tubes should be used with high pressure and only then might the calculations provide some value. You often can't see the seam unless you look closely, and even then you mi...

Did you get back into the hobby after a while? I think that's the same cannon from back in 2013. It's a beast. What mix are you using it at currently?

I found I have to purge my meter pipe with propane to get the air out before fueling, otherwise the first shot will be weak and funky because the meter has an atmosphere of air in it.

Also, regarding the mixing issue, I don't think the fuel/air mixture is an issue at all. I'm betting it's a fuel/air ratio issue. I thought the same about my last cannon but it turned out to be a ratio issue because I didn't measure my meter pipe volume accurately enough. It fixed it. No mixing requ...

50X? Remote fire it behind a blast shield. Regarding the spark at that mix, I'm not sure that will work. Too much resistance. You'd need a lot fo voltage and a tiny gap. A guy named Larda on this forum made a very high mix hybrid and I think he used a wire inside the chamber and ran current through ...

When I chrony my cannons, I have to have the chrony about 10 to 15 feet away from the muzzle, or else the gasses pass over the chrony first and give readings of over 2000fps.

A customer of mine asked me to design them a silencer for a 9mm handgun. We live in California, and possession of silencers is illegal in California unless you have the proper paperwork or authorization. I didn't ask or pry about their legality status as it's none of my business. I wouldn't think DR...

That's actually pretty good. It actually looks exactly like many sketches I've seen over the years in machine shops. A lot of places work off of sketches just like that. The information content is what matters, and as long as they know what to do, then the drawing is just fine.