Gunsmithing Miniature cannon project

[rero360]

For a school project, I have been building a miniature cannon, it was that or miniature steam engine, maybe I'll do that the second half of the semester. I fully intend on making it fully functional. Its not completely done yet but I thought I'd share some pictures of the progress.

The barrel was made from a 12" long 2.5" diameter piece of 4140 steel, it was sent out to another shop that specializes in deep hole drilling to drill the bore which is .50" in diameter and to a depth of roughly 10.25" I intend to mill out the trunnions from the band of metal you see in the middle and if need be drill and tap them for extensions to bring them to the outer edges of the side plates of the carriage.

The carriage is comprised of a mild steel square stock axle, turned down on the ends to accept the wheels which I purchased and are sand cast aluminum. The side plates are also mild steel and the trail is 6061 aluminum. The trail still has a fair amount of machining to be done to it to shape it. Also will need to drill and tap it for the elevation screw. The top straps to hold the cannon in place on the carriage will be made out of brass.

And for a nice little touch, the wheels are kept on the axle via AR-15 firing pin retaining pins. I will update it as progress is made, and should have videos up of the barrel being turned as well.

 

[The Lawn Ranger]

Re: Miniature cannon project

Are you an ID student?

 

[rero360]

Re: Miniature cannon project

Machine shop tech and engineering design, doing a dual certificate program. I already have a bachelors in business, but after I finish this program I may transfer to another school and get a B.S. in manufacturing or mechanical engineering.

 

[The Lawn Ranger]

Re: Miniature cannon project

Good luck to you. The cannon looks very well put together.

 

[Apothus]

Re: Miniature cannon project

That cannon looks so awesome. I've always said that I wanted a cannon. One of these days, I'll find one for sale that's not insanely expensive

 

[SDWhirlwind]

Re: Miniature cannon project

Now that is a pretty kool project. Have always wanted to do about the same but have no mill. How do you decide what steel, thickness etc to use. Always figure I will end up with a fancy schmancy 'grenade' on wheels. Then afterwards I will hear the "well you dumbass, why did you use XXX steel, you shoulda known it wouldn't hold a charge like that"!!!

Will look forward to your progress and more pics. Thanks.

 

[Moose72]

Re: Miniature cannon project

Nice cannon.. My Gf bought me a Mini Cannon for Xmas.. I can't wait to shoot it, I haven't had any time yet.. I also need cannon fuse, and .36 balls as well, but it's neat looking.

 

[rero360]

Re: Miniature cannon project

Thanks gentlemen, I did a bunch of research online first, for the barrel metal, the original ones were cast and from weaker material, bronze, copper, cast iron. I just followed the formula for material thickness for the old materials, one caliber minimum for wall thickness: so its a .50" outside dimension of the tube from the end to the trunnion roughly 1.97" which makes the wall thickness of .735" so almost 150% of the bore.

for the carriage, I figured the real ones were wood so any metal pretty much should be better, and I found the prints online for a revolutionary war era one but I liked the looks of the civil war era so I took it and modified it to suit my needs and wants. Its not going to be a 100% reproduction as in drilling and tapping the hole for the elevation screw will be easier on a flat plane than an angle, should have the trail fully fleshed out by the end of tomorrow unless we have other jobs to do.

 

[rero360]

Re: Miniature cannon project

Plus when I test fire it I plan on using a long slow fuse and being far far away and behind something substantial.

 

[dinc]

Re: Miniature cannon project

Lassen College's Summer NRA Gunsmithing Program used to offer a cannon class. Haven't had it for a couple of years but this guy used to teach it.

George Gaskill
email: [email protected]
13045 S. East End Av
Chino, CA 91710

You could try to get in touch with him for hints and other info. They used to do tennis ball cannons and beer can mortars. Fun stuff. Your cannon looks great.

 

[Keith Johns]

Re: Miniature cannon project

Very kool

I made one in high school and just recently got rid of it after 10 years.

For fuse...
www.cannonfuse.com

 

[rero360]

Re: Miniature cannon project

In between doing actual work I managed to get some work done on the trail of the carriage. I did a rough layout and then giving myself a healthy padding, I rough cut it out on the band saw.

So all I need to do now is finish the contour on the trail, drill and tap a hole on it for the elevation screw, create the trunnion caps, drill and tap the holes to secure them to the side plates, and do the finish work on the cannon that I mentioned above.

 

[rero360]

Re: Miniature cannon project

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[dwtaylorpdx]

Re: Miniature cannon project

I built one smaller back in high school, used a model rocket ignitor to fire it from a safe distance the first few times.

Dave

 

[Straight Shooter]

Re: Miniature cannon project

We have a 50 cal my son built in high school. Mild steel. Walls are 1.5 times as thick as the bore. We proof tested it to 1.5 times our max load. We mic it after every outing and it has never grown a bit. It's just as loud with a bit of paper towel packed into it or shooting patched 50 cal round lead balls. We shoot the same max load that 50 cal muzzle loaders shoot. I would say it's as much fun as Tannerite.

 

[rero360]

Re: Miniature cannon project

So I finally got the program written, with some help from my boss and a few of the other guys in the shop who have more experience. Yesterday I got the cannon loaded into the CNC, a Haas VF2, and started cutting the band down into the trunnions. Due to a misunderstanding between me and my buddy who drew the original solid up in Solidworks, the X origin was off by a bit, which was realized after the second op. Luckily due to the design and the program, I was able to just rotate the cannon 90 degrees and start over again, after fixing the problem and rezeroing the X axis.

I used MasterCAM 6X to write the toolpaths and its coming along well so far, doing one side at a time, with an estimated machining time of 4 hours per side. If I had access to better tools and could make a more rigid set up I could be more aggressive with my feeds and speeds and depths of cuts, but I really don't want to break tools and seeing how we don't have any jobs requiring both VMCs I don't mind taking it slow and conservative.

Here are some pictures of the setup and the progress so far, had to stop about halfway thru the program, ran out of time, should have it done Monday morning.

 

[rero360]

Re: Miniature cannon project

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: *Straight Shooter*</div><div class="ubbcode-body">We have a 50 cal my son built in high school. Mild steel. Walls are 1.5 times as thick as the bore. We proof tested it to 1.5 times our max load. We mic it after every outing and it has never grown a bit. It's just as loud with a bit of paper towel packed into it or shooting patched 50 cal round lead balls. We shoot the same max load that 50 cal muzzle loaders shoot. I would say it's as much fun as Tannerite. </div></div>

Awesome, sounds like tons of fun, being able to do it with your son is a huge plus. Glad to hear that mild steel is up to the challenge, so my 4140 will be even more so. I guess I'm overly cautious when it comes to this stuff, even when I know it'll be safe I still err on the side of caution, me and some friends are going to test fire it when its all said and done and I'm considering building a sandbag bunker to enclose it for the initial shots just in case it does grenade, so no one will get hurt.

 

[Straight Shooter]

Re: Miniature cannon project

For proof testing we just used a long fuse and made sure to keep some earthen barriers between us and it. It has proven itself to be safe to repeated proof tests of 200 grains. Our max noise load is 150 grains. Typical cannon loads are supposed to be something like 60 grains of powder. Lame O.....h. 100 grains is better but 150 grains rock!

 

[rero360]

Re: Miniature cannon project

Was able to get on the machine and finish the second half, work has been busy hence the delay:

I had an additional cleanup pass with a 3/32 ball endmill but I decided to skip it as I actually like the look and effect of the 3/8 bull endmill. The band left around the tube is roughly .013" tall, overall I like how it looks, adds character to the whole thing.

I'm expecting to load up the trail into the mill tomorrow and clean up the contours down to final dimensions. I figure while that is going on I can mill a small flat on the top in the rear and drill the hole for the fuse, I'll do that on the manual Lagun.

Baring any unexpected tasks at work come up, I should have the whole thing done by monday at the latest, top straps should be quick and easy to make.

 

[northern50]

Re: Miniature cannon project

This is awesome. I love projects like this, I've learned a lot by taking on projects and figuring things out as they are built. Nice machine work!

 

[rero360]

Re: Miniature cannon project

Final update:

I finally finished the cannon, last weekend I took it out and test fired it, started with 35 grains of powder with just a patch and then 75 grains with a patched lead ball and then finally 100 grains with a patched lead ball. The cannon fired just fine and I probably could have doubled the powder charge with no concern for safety. Sorry about the poorer quality picture. The barrel was Black Oxide treated by a semi local company who did the work for free as this was a student project.

 

[wtopace]

Re: Miniature cannon project

The final product came out looking amazing!!

 

[JuniperEyes]

Re: Miniature cannon project

Very cool project!

A video of it being fired would be awesome...

 

[11B-B4]

Re: Miniature cannon project

just dont let it end like this...

http://www.nbcsandiego.com/news/local/Cannon-Death-Portrero-Valley--141569173.html


looks cool though. Video would be fun to watch

 

[Sportin Wood]

Re: Miniature cannon project

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hang-fire</div><div class="ubbcode-body">A video of it being fired would be awesome... </div></div>

+100000