Author Topic: Where to find write up on O2 Tank Cannon (Read 3284 times)

Double D · « **Reply #30 on:** February 13, 2012, 07:31:46 PM »

Something else you might want to look at is the safety rules of the American Artillery Association for the construction of mortars and there barrel length.

After tonight meeting at the gun club and one more whipping boy session over balls leaving the range, I again reassured the club we were safe and would adhere to the safety rules of AAA.

If we hold the mile bowling ball shoot, a mortar will have to comply with those safety rules.

jamesfrom180 · « **Reply #31 on:** February 14, 2012, 04:37:03 AM »

DoubleD: Thank you for your explanation and I too agree your picture is worth a thousand words. Fouling is a great point and in considering it the joint of any connection within the chamber would need constant inspection including a vent liner. It is very easy to inspect a mechanical joint as apposed to a weld. But I would offer that by locating the weld of the "tank" between the muzzle and vent you may get the best of both worlds. As far as amateurish if its a better design then what it looks like has alittle less bearing. Though a seacoast style mortar is very nice looking.

GGaskill: By using a set of rimbases you could pass any stress to the trunnions also and in the process greatly increase the weld length beyond using just the trunnion.

CannonSalute: I hope you don't mind but I took your drawing and edited it to illustrate my idea. I will add that I have not built this and have never seen this design.

DoubleD has pointed out to me that in most cases it is best to use designs that have been built and proven. I offer just my opinions and ideas. A quick search yielded a similar design in this thread http://www.gboreloaded.com/forums/index.php/topic,36962.0.html the builder it appears even proofed the design. The effects of long term use still are unknown and do not fully answer the design questions.

Also of note it has been mentioned further in this thread that welding near or around the chamber may create uneven heating. Uneven heating can lead to hardening and changes in metal crystal latices upon cooling. Proper welding techniques can limit this problem, but different designs may eliminate this all together.

Cannon salute · « **Reply #32 on:** February 14, 2012, 06:27:07 AM »

Thanks for the clarification Douglas

Cannon salute · « **Reply #33 on:** February 14, 2012, 06:29:46 AM »

Quote from: jamesfrom180 on February 14, 2012, 04:37:03 AM

DoubleD: Thank you for your explanation and I too agree your picture is worth a thousand words. Fouling is a great point and in considering it the joint of any connection within the chamber would need constant inspection including a vent liner. It is very easy to inspect a mechanical joint as apposed to a weld. But I would offer that by locating the weld of the "tank" between the muzzle and vent you may get the best of both worlds. As far as amateurish if its a better design then what it looks like has alittle less bearing. Though a seacoast style mortar is very nice looking.

GGaskill: By using a set of rimbases you could pass any stress to the trunnions also and in the process greatly increase the weld length beyond using just the trunnion.

CannonSalute: I hope you don't mind but I took your drawing and edited it to illustrate my idea. I will add that I have not built this and have never seen this design. DoubleD has pointed out to me that in most cases it is best to use designs that have been built and proven. I offer just my opinions and ideas.

James, I understand your idea and I believe it would work fine. It just wouldnt give the look most people are looking for.

jamesfrom180 · « **Reply #34 on:** February 14, 2012, 07:42:03 AM »

I agree!
Profile wise the chamber does look odd. But to anyone familiar with mortars or cannons the O2 tank thickness is also odd. That said we were discussing your design CannonSalute, and after all its yours.

Make it your own. So far seems you are asking the right questions and asking the right people. I can't wait to see your final creation.

Cannon salute · « **Reply #35 on:** February 14, 2012, 10:54:29 AM »

I'll definitely post pictures once I start making it. Ill cut the end of the tank first then get the machining done on the chamber. I'll price some materials before deciding on a 4" or 6" chamber.

Cannon salute · « **Reply #36 on:** February 14, 2012, 11:34:35 AM »

Updated drawing

BoomLover · « **Reply #37 on:** February 14, 2012, 12:25:06 PM »

That is a pretty interesting design, Cannon Salute...I like it and think it may have potential! It would be interesting to do it and see how well it works...looks like less welding, and the tank is sitting right on the base. Powder chamber looks about sturdy enough, is the "1 caliber" rule followed on all sides and bottom of the actual powder cavity?

BoomLover

Cannon salute · « **Reply #38 on:** February 14, 2012, 12:30:41 PM »

The chamber breech wall will be atleast as thick as the walls, in that design the breech wall is 4" thick. That is only because I havent found a 4" round 6" long. I can only find 8" long pieces so far. I might change it up and use a 6" round for the chamber, but the price for that is $150. I am trying to keep the price low.

Cannon salute · « **Reply #39 on:** February 14, 2012, 01:09:36 PM »

Quote from: Double D on February 13, 2012, 07:31:46 PM

Something else you might want to look at is the safety rules of the American Artillery Association for the construction of mortars and there barrel length.

After tonight meeting at the gun club and one more whipping boy session over balls leaving the range, I again reassured the club we were safe and would adhere to the safety rules of AAA.

If we hold the mile bowling ball shoot, a mortar will have to comply with those safety rules.

Hmm according to the American Artillery Association's Mortar Safety Rules, barrel length shall not exceed two times projectile length. So if a bowling ball is roughly 8.5" that means barrel length must be at most 17 or 18". I gather you measure from the muzzle of the chamber when measuring barrel length. I was wanting to do around a 48" barrel, but it seems only a mortar can be made using an O2 tank. Firstly because you need the trunnions on the chamber to provide support, and secondly it would be hard to pour powder into a cannon if it didnt have a steep angle.

Double D · « **Reply #40 on:** February 14, 2012, 01:38:33 PM »

http://www.americanartillery.org/aaa/mrt.html
Barrel length shall not exceed 2 times the projectile length, while projectile length shall not exceed 3 times the bore diameter.

48 inches is far to long. Cut it to 18 inches it will look better and be more stable. In this type of mortar there is no advantage to f longer barrel. In fact since the barrel is nothing more than ball holder and expansion chamber, the longer barrel night increase drag as the ball is launched.

Actually these tanks have a strong very resemblance to the profile the Confederate 24 PDR

Move the weld as far from the muzzle as you get it. You also do not want weld over the chamber. The heat of welding can create a hard spot and possibly a brittle spot. Probably not a real issue, but you you don't need to take tyhe chance.

This is a big impressive mortar and up might as well make it look good. Build for safety build. for efficiency and build for looks. You will never regret it..

Double D · « **Reply #41 on:** February 14, 2012, 02:03:41 PM »

oops you already responded...I wrote this up a couple of hours ago and forget to hit post.

Cannon salute · « **Reply #42 on:** February 14, 2012, 02:12:12 PM »

No big deal, I revised the drawings, let me know what you think.

Cannon salute · « **Reply #43 on:** February 14, 2012, 04:43:28 PM »

Quote from: Double D on February 13, 2012, 05:54:54 PM

The vent goes into the back of the power chamber and not the front. The vent provides an unbroken path from out outside to the powder chamber.

I have posted my version of a vent tube a number of times. I make mine from socket screws or bolts.

I put the screw in the lathe in a screw mandrel I made to hold the screw Drill a pilot hole with a center drill to get through surface hardening.

Then drill the rest of the way through.

Here the vent liner is in place in my popcan mortar.

Here you can see the hole through the screw.

The big screw, that will be the vent liner for my bowling ball mortar.

I cant see any welds on the trunnions or on your chamber on your soda can mortar. Where did you weld the trunnion.

Double D · « **Reply #44 on:** February 14, 2012, 05:30:46 PM »

Those are K.I.S.S. Mortars they have no welds!

Here is the thread on the K.I.S.S. bowling ball mortar

Cannon salute · « **Reply #45 on:** February 14, 2012, 05:36:43 PM »

So how is the trunnion attached? And is the chamber presfitted or sweat fitted?

Double D · « **Reply #46 on:** February 14, 2012, 05:41:55 PM »

Like the drawing says, bolt on. Everything is slip fit.

Click on the link...

jamesfrom180 · « **Reply #47 on:** February 15, 2012, 02:48:48 AM »

You may need to increase your trunnion length.

I like it really does look like an older pattern.

Cannon salute · « **Reply #48 on:** February 15, 2012, 01:42:29 PM »

Updated drawing based on materials I have been able to source at reasonable costs. Will be using 4" Diameter Round Stock, 6" long. A 6" round has an exorbitant cost that I cannnot justify for this project. Does 2" thick breech wall sound sufficient?

Cannon salute · « **Reply #49 on:** February 15, 2012, 02:44:48 PM »

Quote from: Double D on February 14, 2012, 05:41:55 PM

Like the drawing says, bolt on. Everything is slip fit.

Click on the link...

Reviewed the link am I understanding that you driiled and tapped a hole behind the chamber? Doesnt that violate the safety rules?

GGaskill · « **Reply #50 on:** February 15, 2012, 03:58:27 PM »

The holes are to the sides of the chamber.

Cannon salute · « **Reply #51 on:** February 15, 2012, 04:02:01 PM »

Oh ok, so the trunnion is just bolted to the chamber and the tube is slipped over it with nothing holding it in place?

GGaskill · « **Reply #52 on:** February 15, 2012, 04:12:29 PM »

The breech interlocks with the tube and the trunnion holds them all together. Look at the bottom drawing more closely and you will see this.

What is not obvious in the sectioned drawing is that the trunnion bears on the tube.

Double D · « **Reply #53 on:** February 15, 2012, 04:41:21 PM »

If you will click on the links provided and read the post there you will understand what is going on-there is a complete description in the post on how this works. You will also get some ideas on how to build your gun.

Cannon salute · « **Reply #54 on:** February 15, 2012, 05:18:10 PM »

Ah yes now I see the lip on the chamber and tube and where the bolts are. After some initial measurements I have found that if I cut the threaded portion of the tank off at the base it will leave a opening about 3-5/8" in diameter which means a 4" round wont fit unless I machine down the breech of the chamber so it has a lip like your design. Either that or cut the tank so that it has a 4" opening.

Double D · « **Reply #55 on:** February 16, 2012, 05:10:54 AM »

My turn to say your drawing sucks...

Here's what you have so far.

Your design meets the safety standards. Weld the chamber to the trunnion, then weld the tank to the trunnion-chamber. Do not try to apply the K.I.S.S. principles to the tanks mortar.

I don't like the look of diameter of the trunnion but that is aesthetics.

Cannon salute · « **Reply #56 on:** February 16, 2012, 05:33:30 AM »

Think it would look better with 3" round? Also I noticed you said earlier dont weld over the chamber, do you mean dont run a bead across the bottom of the chamber when welding the trunnion on? Or are my welds as layed out in the diagram ok?

I know the drawing is mediocre, I have a design program, but I did those drawings quickly on paint. I'm going to start taking pictures soon so no more drawings will be needed!

Double D · « **Reply #57 on:** February 16, 2012, 10:13:43 AM »

3 inch does look better....

Don't worry about your drawings---I took one whole semester of introduction to AutoCad last fall and I just showing off.. prior to that only used P&P 1.0 for dry erase boards to draw... (Paper and Pencil= P&P)

I think if you build the mortar in the drawing you will have a mortar that will look good and work well.

Have you hought about a base? Here is an idea!

KABAR2 · « **Reply #58 on:** February 17, 2012, 03:06:13 PM »

I think he may be using what I use for drawings at work..... Microsoft word......
I wish I had Autocad.......

BoomLover · « **Reply #59 on:** February 19, 2012, 04:08:13 PM »

Ok, here's my question...I have several oxygen tanks, (diving), that are 6.75 inches I.D. The closest projectile to that diameter that I have readily available are Coffee containers, which measure 6.5 inches. Using the 39/40 rule, ideally the I.D. would be 6.6666 inches. I figure that is pretty close, for windage. So, if I use the same plans as posted by Double D on the 16th, given the scale-down from Bowling Ball Mortar to this one, what size stock should I be looking for for the powder chamber, and what would be the ideal depth and diameter for the actual powder pocket? Also, given the smaller diameter tank, what would be the optimal size trunnion? Thanks, BoomLover