Seamless tubing: safe?

AeroE,.... I've "double checked" yore figger'n, and I agree!! :redthumb: :haha: :applause: ::

YMHS
rollingb

 

People from Missouri sure are smart :thumbsup: Welcome, AeroE.

 

[Zonie]

Welcome AeroE: From where I sit, we are basically in agreement on everything, including the danger of not knowing exactly what the material and its "condition" are if someone goes down to the local steel yard and buys "some seamless tubing" to make a gun barrel out of.
I think you will agree that because things like the pressure in a barrel are not constant, anyone seriously contemplating using thin wall tubing for a barrel needs to have some serious structural analysis done first.

Now that we got's all o that simpul enganeerin dun, we needs ta get bak ta tha fun stuff O talkin bout muzzloading. ::
Iffen Ah wanted ta do all O this hard thinkin stuff, Ah wood hav stayd down at work. :: :: ::

Kick back with tha rest O us an join inter our diskussions on lots o othar stuff! Yeer always welkum.

 

Local pipe yard seamless tube.... May be like the guy who went to the doc after makein and shotin such a gun. He had 10 fingers missing. The doc asked if he had his finger to reattach ?. He asked the doc WHAT? Reattach?... Doc told him yes with todays medical technology they can now reattach them....
The guy said I would have brought them with but how the he11 was i suppose to pick them up?!! :crackup: :crackup:

Woody

 

[BLAHMAN]

I would like to make a couple of comments -

In application, here is the way I would use this formula:
1) Estimate the actual operating pressure, P.
2) Establish a Factor of Safety (F.S.) to use against the operating pressure. The purposes of a Factor of Safety are to accomodate variations in workmanship, variability of material properties, errors in the engineering methods, and uncertainty in the design load (operating load). In fact, for pressurized system design, I will use two factors of safety; one to cover for burst pressures or Ultimate Load where the part will be on the verge of catastrophic failure, and a smaller one that I will as proof pressures or a Limit Load case where I will insure the part does not yield or deform sufficiently to inhibit it's function.
3) Establish the allowable stresses (F) for the selected material, including a knockdown for operation at elevated temperatures (although this is a minor consideration in a muzzleloader).

Ok everybody, heads up! I will put this into layman's terms we can all understand. After reading this and much podering this is what I came up with.

1) Estmate the actual operrating pressure, P

Ok, this means, how much nagging from the little women can you endure before actually taking out the garbage?

2) Establish a factor of safety (F.S.) to use against operating pressure.

This means: trying to figure another excuse to not take the trash out now, but in fact to promise to do so at a later date, which is never specified. Ya gotta hope she does'nt stand there, arms folded giving you that stare. If that happens your toast!

3) Establish allowable stresses (F) for the selected material.


This is where it really gets tricky. If the trash isn't taken out NOW when she demands, and if you drag your feet about it anymore will she really, and I mean really, get mad?

Here are some examples:

WIFE "Honey, could you take out the trash? It's full and kinda overflowing."

That deosn't equate to to much P, but it can build up like this:

WIFE "You'd said that you'ld take care of it and that was last week!"

Now the pressure is a bit more. But it can get worse, watch:

WIFE "Your setting a bad example for your children!"

See how much pressure that causes?

Now, it is time to establish the factor of saftey (F.S.). We can determine this by the following excuses that we ussually have at our fingertips. Some of these are:

1) "Right now????" This is not a good excuse and doesn't allow for much safety, and can be easily defeated.

2) "Ya know, I gotta hangnail and it really bothers me, I could get an infection ya know." This is better, but can still be defeated.

3) "Ok Dear, I'll get to it right away." This, is the best and most durable excuse because you have't denied to do it, you've simply said that you will, but, the trick is that you've never said when. It could take forever. See how strong a statement that is?

Now comes the awfull truth when we establish the total alowable stress (F) in the whole theory.

WIFE "If you DON"T take this trash out RIGHT NOW, I'm going to dump it in your SHOP! Do you hear hear me MISTER?"


This is the most allowble stress in the whole scheme of things. At that point, we must, for the sake of our personel space and sanity take out the trash.

Now, does everybody understand this when when put into simple terms? Good, now I hope AeroE will ask a much more complicated question like: "What's for supper!?"

 

[Slash]

I am by no means the smartest one here, but it seems that some of the barrel makers could answer the questions about the safety issues. Blackpowder Barbie deals with a number of them and maybe she can help get the info on tensile strengths, etc. I have no idea how many builders use them either.
Slash :m2c:

 

BLAHMAN,.... I've "double checked" yore figger'n, and I agree!! :thumbsup: :redthumb: :applause: :applause: :: :haha:

YMHS
rollingb

 

[AeroE]

Okay, that's pretty funny.

AeroE --> :yakyak: <-- MrsAeroE

 

[musketman]

That's interesting, how do they make seamless tubing?

Two ways...

1. From a solid rod, drill it lengthwise to make a seemless tube...

2. Forge and draw method, forge a steel pellet and use a series of dies to draw the metal around a bar template to form the tube's outer walls, then the rod is removed to expose the tube...

 

[BLAHMAN]

Okay, that's pretty funny.

AeroE --> :yakyak: <-- MrsAeroE

You get that at your place too?

 

[Rusty Old Gunns]

Joel.

You say "On the Tennessee Valley Manufacturing web site, Jack Garner says his shotgun barrels are made of tubing."

The only web sight I could find for Tennessee Valley Manufacturing is http://www.avsia.com/tvm/ and they don't mention tubing, or even Shotguns.

Since Shotguns are a love of mine,if you have another URL, I'd love to see it.

 

[BS]

I agree that even afer all the math is done, the most important part is the proof testing!

 

[MRW]

I use a 4130 seamless aircraft quality tube for my shotgun barrel. When I tested a 12" section prior to making a barrel i used a greases bore size 2 ounce lead slug ahead of 250 grains RS pyrodex. I fired this load three times, we miked the barrel in three places at the breech end prior to test firing and again after and could not determine any stretch or damage due to pressure, this is one inch tube with a .156 wall for a .682 bore (15ga) I have used this for three years with no problems, of course my maxiumum load is 90 grains of RS pyro behind 100grain setting of shot two hard cards no cushion and one over shot wad.

 

[Joel Lehman]

The web site is[url] tennesseevalleymanufacturing.com[/url]. It says they make their own barrels. My mistake. I must have been thinking of the Early Rustic Arms website concerning the tubing.

 

[Slamfire]

Method #1 sounds suspiciously like the way you'd make a gun barrel. So the difference would be, a)the material? b)the wall thickness? c) all of the above? :hmm:

 

[bezoar]

yes it does indeed. and cannon people use it to sleeve those infernal cannons of theirs.

But seriously, i dont see how a 23,000 psi peak pressure from a charge of bp and a round ball is going to affect hydraulic tubing thats designed for 100,000 psi peak loads all day long....

 

[CrackStock]

http://www.tennesseevalleymanufacturing.com/

http://www.tennesseevalleymanufacturing.com/catalog.php?category=barrels