Author Topic: new cannon (Read 1752 times)

porta mill · « **on:** April 24, 2011, 06:21:23 PM »

well after a lot of research and time my cannon is almost finished, and more pic's and video to come.

porta mill · « **Reply #1 on:** April 24, 2011, 06:27:41 PM »

more pics

porta mill · « **Reply #2 on:** April 24, 2011, 06:43:50 PM »

just figured out how to post more than one pic at a time .

moose53 · « **Reply #3 on:** April 24, 2011, 07:30:48 PM »

Really hate to see a stressed tube ringed with weld . You may not have any problems that far forward , but its not a good idea. I worked in mill repair and saw some spectacular failures , some of them my work . You tend to learn from that kind of thing.

RocklockI · « **Reply #4 on:** April 24, 2011, 07:36:45 PM »

Welcome porta mill !

.

Did you research your cannon on this site ,or somewhere else ?
This is the place for cannons !
Gary

Double D · « **Reply #5 on:** April 25, 2011, 01:14:11 AM »

That tube looks to me to be a piece of welded seam pipe. Not good material for a cannon barrel. If it ds seamless it will need to have the bore machined smooth.

Also because of all those welds you now need to anneal the entire tube.

How did you do the breech plug?

Cat Whisperer · « **Reply #6 on:** April 25, 2011, 01:48:05 AM »

Portamill -

WELCOME to the board!

Good start IF....

We've raised some issues that need to be answered, even if the answers are hard to take.

I've seen a cannon explode from about 15' away. You NEED to know, when you light the fuse, whether it's a cannon or a bomb.

Pipe or tubing with a seam will fail over time. Maybe in your ownership, maybe later. Where there are welds (the seam in the pipe) you will have porosity - into which the products of combustion will seep - and corrode - weakening. They will develop into cracks. Cracks give way suddenly and without warning (with steel).

If you have any doubt set it up as a carbide cannon. Big bang, no pressure to speak of.

porta mill · « **Reply #7 on:** April 25, 2011, 07:39:19 AM »

I guess I should have explained the build first . The breech is solid. I bored it out to accept the barrel . the barrel is is counter boared 5 1. 1/2 into the breech . the barrel is seamless p22 chrome molly . The barrel is then welded to the breech , the cap that holds the trunnions slips over the first thenthe cap is welded to the barrel . so where the explosion happins there is sufficiently material.

Cat Whisperer · « **Reply #8 on:** April 25, 2011, 07:46:42 AM »

Coooool!

Please take our commnents as looking out for your safety. DD's comments about the welding is good - anneal it to relieve the stresses.

Keep the pix coming!

Double D · « **Reply #9 on:** April 25, 2011, 03:33:55 PM »

First let say I an glad hear you used real seamless. but beyond that I am a bit baffled and confuse. Slipped the barrel in side the breech? So barrel is in side the breech. Can you draw me a picture...that doesn't sound right...be gentle with me I am elderly and on meds.

So how did you seal the bottom of the barrel?

porta mill · « **Reply #10 on:** April 25, 2011, 04:38:26 PM »

I will try to explain this as simple as I can. the largerend I will cal the breech , that started out as one solid piece. I first bored a hole in the breech with a lathe making many passes until I had a snug fit of the barrel . The barrel was then pressed in and welded . the section the trunnions are welded to is another piece I bored that piece so it would slip over the barrel so that it would cover the first weld. then welded that piece to the breech and also to the barrel. I hope that helps

Double D · « **Reply #11 on:** April 25, 2011, 05:14:54 PM »

Quote from: porta mill on April 25, 2011, 04:38:26 PM

I will try to explain this as simple as I can. the larger end I will cal the breech , that started out as one solid piece. I first bored a hole in the breech with a lathe making many passes until I had a snug fit of the barrel . The barrel was then pressed in and welded . the section the trunnions are welded to is another piece I bored that piece so it would slip over the barrel so that it would cover the first weld. then welded that piece to the breech and also to the barrel. I hope that helps

Your barrel has no breech plug it has a breech cap. At the bottom of the barrel where it seats against the breech cap botton is a seam. The sean is in one of the worse possible places a seam can be. A press fit is not going to seal the seam and stop fouling and moisture from collecting there. Corrosion will start there and it can and will weaken the barrel and/or trap a spark.

What you need to do is turn the breech cap off the barrel and make a proper breech plug that is heat shrinked in place and then weld it. Go to our sticky at the top of the forum called Safe Loads and Construction click on the link in the post to the North South Skirmish Association rules and scroll to section 10 and you will find the instruction for making a proper breech plug.

After you get the plug in then you can add a bit of taper to the forward half of the barrel and add your breech ring, knob, vent liner and trunnions, and you will have a right nice Parrot gun.

porta mill · « **Reply #12 on:** April 27, 2011, 05:14:20 AM »

Well I guess I need to built a new cannon since this one is not up to safe standards . I believe you guy's know more about cannons than I do . so since for me building in out of one solid piece of material is not an optsion I need some help building one correctly . If it is at all possible could some one give me some help with a safe design I am not totally familiar with a few of the terms used in the last post saying my design was flawed ,a drawing would be nice if at all possible. Thank you for any help.

Double D · « **Reply #13 on:** April 27, 2011, 05:35:00 AM »

Click on this link North-South Skirmish Association National Rules.

That link is to a PDF so it may take few minutes to open. Look for section 10.2 Eligibility. At the start of that section is the drawing that shows how to do the breech plug.

You really aren't far off in design and you can salvage what you have. Use the use the barrel tube you have and put in the breech plug.

I'm not sure which term you don't understand, tell us and we will explain. We are more than glad to help.

My criticism is not intended to offend, it is intended to keep you and others who may be around when you shoot, safe.

porta mill · « **Reply #14 on:** April 27, 2011, 04:46:46 PM »

ok I inlisted some help today with the new design . what do you think about this design. I also have a gusetion to ask ? n the link that you I told to look at it says to sweat in the breech plug . Does that mean sweat the breech plug in with silver solder of something else? it also states if the bore is 1" there should be in inch of material each side of the liner. but in that respect they are using cast iron. what is the rule of thumb for steel . in the first cannon I used p22 chromolly for the barrel and a solid chunk of 4" 1018 for the breech plug.

GGaskill · « **Reply #15 on:** April 27, 2011, 05:51:37 PM »

"Sweat" is this instance usually means shrink fit; however, if you could limit the silver solder to just the forward part of the plug and then weld the back, you would have a good seal in front and a strong anchor in the back.

porta mill · « **Reply #16 on:** April 27, 2011, 06:51:23 PM »

shrink fit ? that is interesting . In my original design I pressed in the barrel to breech with a 20 ton press. I was barely able to seat the barrel with the press. I do not know if that as tight as a shrink fit but it is dam tight . Also in my original design there is like 3" of solid material behind the barrel so all and all there is a seam in the breech with either design . So the only difference is the breech plug . Does explaining the first design further make it any more safe is, or it still not a good an design? I want thank everyone for pointing out the flaws in the cannon. I want the cannon to be safe to shoot for years to come. so if you still think the first Cannon is not safe I will De mill it and start over. Is there anthing else that I should take into consideration before I start the next build. thank you for your help

GGaskill · « **Reply #17 on:** April 27, 2011, 09:25:06 PM »

I think if you could get the joint at the barrel/breech cap hot enough to flow a good silver solder joint in there you would be OK. The goal is to prevent corrosion-inducing fouling from getting in that joint where it can't be cleaned out and ultimately weakens the joint.

dan610324 · « **Reply #18 on:** April 28, 2011, 12:45:51 AM »

if you want something to be really proud of you could scale down an existing cannon model
ok , its fun with a shooter , but wouldnt it be even funnier if it looks like an existing cannon model ??
but please always think safety first
yeah you are correct about the cast iron , but can you find any disadvantages to use the same proportions for steel ??

Cat Whisperer · « **Reply #19 on:** April 28, 2011, 12:52:23 AM »

(Dan - I assume you're up late, as I'm up early. Good points about cast iron vs. steel.)

Good points re: assembly techniques.

When the products of combustion get into the steel - in a crack or in a porous area (weld) - it corrodes. Cracks start - once started eventually end in catestrophic failure.

That is to say, there are several ways - silver soldering and shrink fit being two - that prevent the first from happening which precudes the second.

Watch where the welds are up on the barrel - when you weld you create hard spots. Hard steel is more brittle than soft steel. Hard steel when flexed will crack. Normalize or anneal to overcome that - or eliminate the weld. A weld at the back, as in your design is ok - it's been used that way by many folks - it works.

dan610324 · « **Reply #20 on:** April 28, 2011, 12:58:41 AM »

its noon here now
so I wouldnt call it late

Cat Whisperer · « **Reply #21 on:** April 28, 2011, 02:05:24 AM »

Quote from: dan610324 on April 28, 2011, 12:58:41 AM

its noon here now
so I wouldnt call it late

Oh yea. The sun goes the other way, doesn't it.

dan610324 · « **Reply #22 on:** April 28, 2011, 03:14:09 AM »

up in the east and down in the west
but who cares ??
its just details

Double D · « **Reply #23 on:** April 28, 2011, 03:52:43 AM »

First that sleeve and breech plug from the NSSA drawing is not cast iron it is steel, and the drawing shows the minimum standards and every thign can be heavier..

A press fits can and will displace metal and will never make a good seal. Shrink fitting is far better and the metals will compress onto each other as the hot metal contracts when it cools and the cold expands when it warms. I am not all that hot on soldering such a joint as to solder requires a gap and the hat of weld is just going to melt the solder out.

There is nothing wrong with your updated design. Add a knob and you have a basic Parrot gun look. You will have to put a vent liner in. You cold slip fit the cap and epoxy it in place. You would need a couple of set screws as safety lugs to hold the cap in place. You could even set your trunniopns up as the safety lugs. Drill and tap troughthe cap to the barrel for trunnions and then weld them in pllace.

Don't get get discourage because you think we are tearing down your design, we are not. Rather be encouraged that we are helping you fine tune what is a good basic design.

porta mill · « **Reply #24 on:** April 28, 2011, 07:39:29 AM »

I hate to ask a stupid Question but what in knob, and vent liner ? Is the liner the hole the fuse goes in to and also acts as a vent. I am not discouraged. I thought I was on the right track the first time but, I do not build cannons. I will. I will take your advice you guys know more than I do about cannons. thank you for the help .

Double D · « **Reply #25 on:** April 28, 2011, 08:08:37 AM »

Knob is weel the knob, trhe round ball on the end. Vent liner is a tube that goes through the hole for the fuse and makes a continuous path so that the seams between the various section of the cannon are protected from contamination by fouling.

dan610324 · « **Reply #26 on:** April 28, 2011, 11:19:48 AM »

maybe it all started in the wrong end here .
what skills and possibilities do you have to use machines ??
what equipment do you have access to ??

porta mill · « **Reply #27 on:** April 28, 2011, 12:45:38 PM »

I have a small machine shop where I work . two lathes a bridgeport CNC lathe (I do not run CNC). band saws torches multiple welders . I think the machinery I have at my disposal is sufficient to build the cannon . Is there anything else I need . I am not a pro cannon builder that is why I am here asking for advice and I appreciate the help. but I am not a complete Idiot either.I have worked at a two machine shop over the last 12 years I am not a master machinist but I am not new to the equipment either. pulse I have a very good machinist/gunsmith that is helping me with the new cannon.

dan610324 · « **Reply #28 on:** April 28, 2011, 01:57:01 PM »

thats good , then you got both the knowledge and equipment
what bore size do you want to build ??
what model (style) do you want ??

porta mill · « **Reply #29 on:** April 28, 2011, 03:23:09 PM »

the Cannon will be a parrot gun . the bore will be 1.68 to shoot golf balls . basically it will be an upgraded more safe design of the one in the beginning of this thread.