Guidance needed on threading a tube

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BlwnGazkit
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Guidance needed on threading a tube

Post by BlwnGazkit »

I'm having a brain fart and it hasn't resolved itself in a few hours...

I'm setting up to bore & thread a section of 1.5" Ti tubing I cut off a longer section I've used in the past.

Fo some reason I can't get this 7" section to dial in.

I've got it down to +/- 0.0005" at the chuck, but at the end of the 3.5ish inches hanging out, I'm looking at +/-0.014 of runout...

Pointers please!

The older gentleman I used to ask these questions to, passed away this year finally from Parkinson disease. You don't realize all the small ways you miss someone who you known since your childhood...
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Capt. Link.
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Re: Guidance needed on threading a tube

Post by Capt. Link. »

Tubes are rarely straight. You need to turn then bore them. I set them up in a large cats head to cut thread seats before I thread.
-CL
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
Historian
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Re: Guidance needed on threading a tube

Post by Historian »

Capt. Link. wrote: Sun Aug 29, 2021 4:44 pm Tubes are rarely straight. You need to turn then bore them. I set them up in a large cats head to cut thread seats before I thread.
-CL
Following up on the Good Captain's sage observation one can see
the problem of alignment is exacerbated with length. A little known
solution that has been around in a few patents over the last 70 (?)
years is to not try and align the front and back end caps and the
intervening 'disks'.

Googling Patent Number 5,136,923, Aug. 11, 1992, Donald J. Walsh, Jr.
His solution was to thread a larger diameter bored tube extending
the full length of the can, in your case say 7+ inches. Then the
end cap and outer tube alignments do not come into play. The
variations on this theme for example is to mill out say ⅓ of the
tube's length from muzzle end so that whole can becomes an expansion chamber.
Internally, concentric to the tube and outer tube is a perforated steel spool, think
of the spools that threads are wound around. This dissipates heat and introduces
gas disruption.

Walsh simply perforated the barrel extension as previous patents with
different spacing of machined chambers, etc.

Thus if the can is struck or the front caps are off center the bullets
is not effected. Correcting tube concentricity is eliminated.

Just a fun factoid in the history of suppressor design that might trigger some creative juices.

Best.
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Capt. Link.
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Re: Guidance needed on threading a tube

Post by Capt. Link. »

The Walsh patents are complex with a load of disinformation included for free.The accuracy of his machine work will give many the fits.

Fully threaded suppressors has been done at least since Vietnam by Mitch Werbel of SIONICS/MAC, Walsh, Leasure, and myself. If the thread is cut via single point tools then the interior has been straightened. For perfect bore threads including all the angles a line boring setup is required.This is how I do it though the setup and execution is tedious the results are perfect.

Threading the interior allows lighter weight without the need for spacers plus a larger surface area for heat transfer.The irregular surface also effects turbulent conditions. Threading interiors of spacers also benefit from this technique.Walsh used threads for prototyping but not in the product he sold.

If anyone wish to duplicate the line boring/threading technique give me a jingle as its worth knowing.

-CL
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
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BlwnGazkit
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Re: Guidance needed on threading a tube

Post by BlwnGazkit »

Update:

I went back & looked through my notes on things. As it turns out, this tubing I had originally purchases a length of for use as the tube on a monocore build; it didn't need to be as straight since I wasn't relying on it to control runout in any way.

I've ordered some heavier walled Ti tubing and will turn the OD then bore the ID before threading.
quiettime
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Re: Guidance needed on threading a tube

Post by quiettime »

Capt. Link. wrote: Tue Aug 31, 2021 5:34 pm Fully threaded suppressors has been done at least since Vietnam by Mitch Werbel of SIONICS/MAC, Walsh, Leasure, and myself...
The relatively new AB Suppressors Little Bird is fully threaded also. A neat little wrench that is marked with the factory spacing is included and helps the user return to normal configuration after experimenting with different baffle spacing
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Re: Guidance needed on threading a tube

Post by quiettime »

Just had a thought, the original topic on threading is a prime illustration of why you shouldn't just chuck up a barrel and thread the muzzle; barrels are tubes and as such are not perfectly straight, nor are the bores
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