Help threading barrel

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mr fixit
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Help threading barrel

Post by mr fixit » Mon Nov 04, 2019 8:46 pm

Just got a new-to-me Howa 1500 .308 rifle with a 22" spotter barrel. My plan is to cut and thread the barrel at 16 inches, add a suppressor and call it sweet.

My problem is that I've never cut and threaded a barrel. I know it's pretty critical. I have a 12" Logan.

At 16 inches, barrel diameter is .685". The plan is to use a muzzle brake mount based on the Griffen taper mount.

I'm asking for procedures and cautions for threading the barrel.

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Re: Help threading barrel

Post by rickiesrevenge » Mon Nov 04, 2019 11:26 pm

It's like threading any other chunk of metal once it's dialed in true with the bore. Have you done much threading?

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Re: Help threading barrel

Post by #40Fan » Tue Nov 05, 2019 12:09 am

Does your lathe have a spider?

Is the spindle length short enough and bore big enough to fit the barrel through?

There are a couple decent (need to dig to find them) youtube videos that show how to accurately indicate a barrel that would be worth watching.

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Re: Help threading barrel

Post by mr fixit » Tue Nov 05, 2019 12:16 pm

rickiesrevenge wrote:
Mon Nov 04, 2019 11:26 pm
It's like threading any other chunk of metal once it's dialed in true with the bore. Have you done much threading?
#40Fan wrote:
Tue Nov 05, 2019 12:09 am
Does your lathe have a spider?

Is the spindle length short enough and bore big enough to fit the barrel through?

There are a couple decent (need to dig to find them) youtube videos that show how to accurately indicate a barrel that would be worth watching.
Sorry, I should have been more specific i guess. I've done threading, that's not an issue. What I need help with is making sure it's concentric with the bore. I dont have a spider, and the barrel will be too short to fit all the way through the headstock.

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Re: Help threading barrel

Post by ECCO Machine » Tue Nov 05, 2019 1:12 pm

mr fixit wrote:
Tue Nov 05, 2019 12:16 pm
Sorry, I should have been more specific i guess. I've done threading, that's not an issue. What I need help with is making sure it's concentric with the bore. I dont have a spider, and the barrel will be too short to fit all the way through the headstock.
Then don't do it if the plan is for running suppressed. Concentric is less important than axially aligned for the last 1-2" of bore, and if you don't have a way to indicate that and move both ends of the barrel around accordingly, it would be dumb luck to not end up with baffle strikes.

I do lots of barrels that are too short to fit through my headstock, that's easy-you just find or make a rod that fits the chamber end. But without a spider on the back of the spindle or a cat's head to fixture the entire barrel, that axial alignment is gonna be a problem.

I have a spider I made on the back of the Hardinge HCT, which is what I thread most barrels on. I turn brass rods to fit the various bore sizes tightly for indicating

Image

The ones that won't come out of receivers or have features that don't fit in the Hardinge spindle get done on my big machine in the cat's head I made specifically for barrel threading:

Image
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Re: Help threading barrel

Post by rickiesrevenge » Tue Nov 05, 2019 1:41 pm

https://youtu.be/ErVOUVszFjY

http://pacifictoolandgauge.com/lathe-ji ... ional.html

You make a jig like these to dial one in. How big is your spindle bore?

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Re: Help threading barrel

Post by ECCO Machine » Tue Nov 05, 2019 3:46 pm

rickiesrevenge wrote:
Tue Nov 05, 2019 1:41 pm
https://youtu.be/ErVOUVszFjY

http://pacifictoolandgauge.com/lathe-ji ... ional.html

You make a jig like these to dial one in. How big is your spindle bore?

Aaron
Having your work that far out of the jaws unsupported is a recipe for disaster, especially on a small machine like the OP's 12", which is gonna have maybe 1.5" jaw depth to hold onto, what, an 8-10" long part? Tapered cutting, chatter...........the whole damn thing being ripped out of your jaws. Those are just some of the problems you'd encounter with these pitiful excuses for a cat's head. Horrible idea, both of them. No real professional would thread or chamber barrels that way. If they worked, I wouldn't have spent three times as much on materials and a gigantic ball bearing (not to mention many hours of machining) to make the steady & cat's head pictured above.

If you don't have a large enough spindle bore, you're gonna need a real cat's head that is supported in a steady rest.

Also, contrary to the advertisement's claims, brass tipped screws will absolutely mar barrels, receivers and bolts. Use sheet metal or shim stock to protect your work from brass tipped screws.
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Re: Help threading barrel

Post by rickiesrevenge » Tue Nov 05, 2019 5:52 pm

Sorry for trying to help the guy. Won't make that mistake again.

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Re: Help threading barrel

Post by ECCO Machine » Tue Nov 05, 2019 6:28 pm

rickiesrevenge wrote:
Tue Nov 05, 2019 5:52 pm
Sorry for trying to help the guy. Won't make that mistake again.

Aaron
Oh, don't get all indignant. Doesn't suit members of this board. It also doesn't suit this board for any member to keep their mouth shut when a suggestion is made that we know to be a less-than-good idea, ergo my last post.
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Re: Help threading barrel

Post by mr fixit » Tue Nov 05, 2019 10:44 pm

would pulling the barrel and threading between centers be good enough?

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Re: Help threading barrel

Post by ECCO Machine » Wed Nov 06, 2019 12:35 am

mr fixit wrote:
Tue Nov 05, 2019 10:44 pm
would pulling the barrel and threading between centers be good enough?
For a muzzle brake, sure. Not for a suppressor. You might get lucky and have the last inch of bore just happen to align well enough with the breech and muzzle, but I can tell you that most every rifle barrel I thread has well over 1/16" runout on the chamber end by the time the muzzle end of the bore is concentric and axially aligned to <.0005" per inch. Some of them are so snaky that the 1.45" spindle bore on my Hardinge isn't big enough to move the back end where it needs to be for that alignment on the front.
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Re: Help threading barrel

Post by fishman » Wed Nov 06, 2019 3:20 pm

mr fixit wrote:
Tue Nov 05, 2019 10:44 pm
would pulling the barrel and threading between centers be good enough?
Yes and no. If the bore is straight, it'll be fine. Lots of bores arent perfectly straight. Ive done it on a very short barrel. It works but isnt a best practice.
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Re: Help threading barrel

Post by mr fixit » Wed Nov 06, 2019 4:14 pm

So, what are my options then?

Edited to add: I don't have a spider on the outboard of the lathe. Should I make one for it? It currently has an attachment for the collet closer.

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Re: Help threading barrel

Post by ECCO Machine » Wed Nov 06, 2019 5:46 pm

mr fixit wrote:
Wed Nov 06, 2019 4:14 pm
So, what are my options then?

Edited to add: I don't have a spider on the outboard of the lathe. Should I make one for it? It currently has an attachment for the collet closer.
That would be the simplest and best solution. Pretty easy to make, and keeps your work close to the chuck, minimizing chatter & taper issues.

I'll snap a photo of mine later. Its aluminum, 3" OD, about 2" thick, fits the spindle snugly and is secured by a brass set screw.
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Re: Help threading barrel

Post by mr fixit » Wed Nov 06, 2019 6:07 pm

ECCO Machine wrote:
Wed Nov 06, 2019 5:46 pm
mr fixit wrote:
Wed Nov 06, 2019 4:14 pm
So, what are my options then?

Edited to add: I don't have a spider on the outboard of the lathe. Should I make one for it? It currently has an attachment for the collet closer.
That would be the simplest and best solution. Pretty easy to make, and keeps your work close to the chuck, minimizing chatter & taper issues.

I'll snap a photo of mine later. Its aluminum, 3" OD, about 2" thick, fits the spindle snugly and is secured by a brass set screw.
Thank you sir

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Re: Help threading barrel

Post by #40Fan » Wed Nov 06, 2019 6:15 pm

https://www.youtube.com/watch?v=Up90uFBQRtM

Gives you an idea how they are made. Like Ecco said, protect the barrel from the screws.

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Re: Help threading barrel

Post by T-Rex » Thu Nov 07, 2019 1:47 pm

Cuz pics of catheads :)

Image

I just threaded a junk of 1018, so it fit the spindle.
Welded a piece of 2-1/2 or 3" CS pipe to that.
Turned the OD true.
D&T all the socket-head screw holes.
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Re: Help threading barrel

Post by mr fixit » Fri Nov 08, 2019 3:18 pm

T-Rex wrote:
Thu Nov 07, 2019 1:47 pm
Cuz pics of catheads :)



I just threaded a junk of 1018, so it fit the spindle.
Welded a piece of 2-1/2 or 3" CS pipe to that.
Turned the OD true.
D&T all the socket-head screw holes.
Cant see the pic. thought it was because i was at work, but cant see it at home either.

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Re: Help threading barrel

Post by T-Rex » Fri Nov 08, 2019 6:24 pm

mr fixit wrote:
Fri Nov 08, 2019 3:18 pm

Cant see the pic. thought it was because i was at work, but cant see it at home either.
Hmm, works on all my devices.
Anyway, here's a link
Completed Builds www.silencertalk.com/forum/viewtopic.php?t=79895
Burst Calculator www.engineersedge.com/calculators/pipe_bust_calc.htm
Silencer Porn www.instagram.com/explore/tags/silencerporn/

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Re: Help threading barrel

Post by #40Fan » Sat Nov 09, 2019 8:22 pm

I can't see it either.

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