5.56 Form 1 completed

[zevdogs]

When I do internal endcaps I face part, turn OD back 1 inch, thread to size ,part size in half to end up with two .500 pieces and install with machine surfaces in toward baffles then just clean up out side for looks

[wolf]

F--k that Americans don't like it BS. External threading makes a ton of sense in this application. Internal threads are weaker, harder to machine, prone to getting gunked up and galled, harder to clean.

Looks pretty good for 22oz.

He He He you didnt think this through ,, did you

soo lets see

a can with the tube threaded internal = two internal threads (in the tube ) + two external threads (on the endcaps )

a can with external threading =two external threads (on the tube ) + two internal threads (in the endcaps )

no matter how i look at it just as many internal and external threads in both cases

and the exact same machining , only the endcaps with the internal threads would be slightly harder to make , but no problem to do/no big deal

[delta9mda]

wolf knows some s--t!

[tom_penn01]

I have had no problems with threads backing out. I threaded the tube first and then threaded the caps to fit. Everything was done on an sl10 and haas toolroom mill with a rotary table. The stack is longer than the tube. And you sir are correct about the stack compressing. I found this out after I shot it 10 times and shook it. I put a shim in it to take out the slop. However there were no baffle strikes. I have always believed that external caps strengthen the tube because they cover the weakest point on the tube. Is this incorrect?

[wolf]

NO

there is two things that can break , the threads ,or the tube

if the threads is the strongest ,no matter internal or external , then the tube will rupture at the weakest point
this will most likely be at the relieve grove for the threading , or if no grove , at the deepest point of the treads used

in steel it only takes 3 turns to achieve full strength, when you screw in a normal 1/4 bolt

and that bolt is solid

in this case we dont talk about the can exploding due to pressure inside
we talk about the force that is trying to push out the baffles
so what ever is weakest , goes first , and you have baffles down range
either the stack if it was the front or most of the can if it was the rear that went fubar

now if we talk about the pressure trying to expand the can , like a balloon
Then there might be a advantages , sins the tube expanding will have lees grip on the threads

but then you have used a tube that is to thin, which brings up what was written at the top = if the tube can expand , the walls will be weak at the threading, not THE threads ,but the cut into the tube , the tube will break

[wolf]

Of course there is a tricks
Take a look at the Tirant

A thick walled tube that has been turned down on the middle part

the treading is long enough to be strong enough
AND the point where the deepest cut is made

IS IN the thick part of the tube , that part is thick enough , that the cut does not make it weaker than the thin part of the tube

you have a wall thickness AT ALL POINTS that is strong enough

BUT not more than needed =light but still strong

[tom_penn01]

Ah, that makes complete sense. Thanks for the clarification!

[este]

He He He you didnt think this through ,, did you

soo lets see

a can with the tube threaded internal = two internal threads (in the tube ) + two external threads (on the endcaps )

a can with external threading =two external threads (on the tube ) + two internal threads (in the endcaps )

no matter how i look at it just as many internal and external threads in both cases

and the exact same machining , only the endcaps with the internal threads would be slightly harder to make , but no problem to do/no big deal

"He he he"? You might want to think about it some more. Your entire point that there will be 2 external and 2 internal misses all the real issues.

External threads on the tube is going to be larger threads on the tube and end cap. Larger threads of the same tpi are going to be stronger. Always.

With a tube having internal threads, the gas and carbon will be forced between the two threads as it's line of sight to the gas, it's flowing right into the threads (exaggerated for illustration of course). With the endcaps being threaded on top of the tube, that gas would have to make a 180º reversal to gum up the same threads. I would use a external thread with no O-ring. I would not do the same for internal. Iirc, the newer TiRants have internal threads and an O-ring. Because of heat, I would not run an O-ring on the endcap of a rifle can, so.... there for, I would not use internal threads on a rifle can. I would have less issue with external threads.

Next, I am under the impression that external threads are a better idea in a pressure vessel. It's my theory (and I certainly could be wrong) that under enough pressure to make the tube swell, using external threads should make the tube's weakest part push out into the stronger endcaps, the same effect as tightening the cap too much. This to me seems better than the stronger encaps pushing out against the weakest part of the tubing. This is just my impression after looking at pipe threads and pressure vessels that have external threads. But, who knows on that, I'm no engineer.

That all aside, good point about have 2 internal and 2 external threads either way. You're absolutely right in the regard.

[wolf]

If gas had a problem doing a 180 turn then most silencers are more complicated than they have to
BUT gas has no problem doing that 180 turn,,, at least not last time i did look at a motorcycle exhaust

but yes you might get less dirt in those threads

you dont need stronger threads than what you need

they only have to be stronger than the tubes weakest point

easy done

the tube doing a balloon, would make it shorter , the same gas pressing on the baffles will try to make it longer

so you strong threads is only needed on a can short of exploding due to a to thin tube

i would worry more about the tube than the threads

all this in a can with a loose core /baffle stack

[wolf]

External threads on the tube is going to be larger threads on the tube and end cap. Larger threads of the same tpi are going to be stronger. Always.


This to me seems better than the stronger encaps pushing out against the weakest part of the tubing. This is just my impression after looking at pipe threads and pressure vessels that have external threads. But, who knows on that, I'm no engineer.

That all aside, good point about have 2 internal and 2 external threads either way. You're absolutely right in the regard.

Always so if you external thread has 4 turns engagement , you say it will be stronger than a internal will 20 turns engagement ,,,i dont think so

but if yo now say of the same length ,, i have to agree

pipe threads

why do we have the pipe

something has to run through the pipe

the pipe has a hole in it

we dont want to restrict that hole

how do we prevent restriction

AHH a pipe fitting ,,a short section of a bigger pipe with internal threading is used to couple the pipes unrestricted together

can only be done using external thread on the pipe , and internal on the fitting


but why havent any told the best thing about external threads on the tube

[este]

Thread out.

[wolf]

Endcaps that are easy to hold onto ,when you have to unscrew them

but it has its risks ,and that is,,

there is always a pro and contra for each solution

[PaulNoiseLess]

Hi,

“there is always a pro and contra for each solution”

Yes, that’s exactly what It’s all this about. I like external threading in general but in particular when:

1) I’m short on Volume and don’t want to increase length.
2) I’m going to work with Muzzle Breaks.
3) I’m going to work with standalone ND’s.

With regards to holding the stack, what you can do is to build the first and the last part (spacer and/or Baffles) with a shoulder (OD=Tube OD) and give some extra Tolerance. If the stack moves after first shots, just screw more. Use this first and last parts to align the stack.

Best,

Paul

[tom_penn01]

http://www.youtube.com/watch?v=pOLwHpn9PUc

Hey guys
Heres a short video, if I would have thought about it I would have shot a .22mag along with it for comparison. First three rounds are 69smk and the fourth is subsonic. The woodline is 100 yds from my position so thats where the sonic crack is bouncing back from. Tell me what you think!
Enjoy!

[PaulNoiseLess]

Hi,

Your Wife at the end says all. Just two comments for next time, record some un-suppressed shots before testing the Can (for comparison) and remember that the trees and forest in general are not your best friends for this type of films (too much eco around).

For the rest, clean target impact blast and clear sonic crack.

What I most like is your Bench Rest

Best,

Paul

[stimpsonjcat]

Hmmm...yes...it does look familiar.

But that doesn't upset me or anything, nice looking can!

I need to get my 223 can finished up, thanks for reminding me.

[delta9mda]

very nice on the sound reduction. silly with subs.