Threading a barrel without taking barrel off?

[bigngreen]

Ya, I turn at 1100 and thread at 350 rpm, not into the slow turn though that could be slow compared to CNC.

 

[25WSM]

Well I can say that a receiver sticking out of my headstock with the trigger and bases still on spin up pretty smooth. You physically can not feel any vibration in the machine. You got a 3000 pound base it's all riding on. Threading is only a low rpm operation if you choose to run low back gear. Lots of guys run 60 to 70 rpm because they are cutting manually and things happen fast. 60 rpm gives you time to think and react. I manually thread myself but I run the highest back gear I have. It's in the 300 range. The extra speed gets the job done faster and the threads are much nicer and smoother. Even the speed I run is slow and requires me to run high speed steel bits to get that smooth finish. Carbide bits need lots of speed. After 30 yrs of cutting on a manual lathe you get good at it. I did work as a machinist before I set up my own shop and really hated it. But I came into my own when I started building the custom rifles.
Shep

 

[Mram10us]

That wasn't aimed at anyone in particular Mike. People kept saying threading is a low RPM operation, and it is, but to get there you need more RPM's and even 660 RPM's with a out of balanced receiver attached can cause issues.

I know Nathan, I was kidding about your massive arsenal of Cnc machines.

 

[25WSM]

Cnc. What's that?
Shep

 

[Ol' Red]

That last one was a good video too. I think I will try that on my most expensive rifle that I have not even shot yet. It was made my Kirby Allen at APR in 338 AX. His rifles shoot 1/2 MOA at 800 yards. I bet I could cut that in half after watching the video.

And it could look like it was done at home- Bonus.

 

[tobnpr]

If one could chuck up the barreled action and have the bore concentric it can be done.

Like I said before, turn a snug-fit mandrel for the bolt raceway if you don't have one. Stick it in the receiver, lock it down, chuck it in a collet or set-tru chuck. Muzzle in a precision live center. Turn down/cut the tenon, put it in the steady. Cut the threads, crown it, and done. Can't be anything but concentric to the bore.

For some reason, working between centers- including chambering (which btw, is still done that way by McMillan, Kelbly's, USMC, and many others) is now frowned upon by the "experts".

 

[Meats25]

it also depends on the barrel taper

I always assumed the barrel needed to be taken off in order to thread the muzzle ?
Is this correct, or is it like I just read on a different thread?
"Any gunsmith that can't thread a barrel without removing it shouldn't be a gunsmith."

 

[J E Custom]

@J E Custom doesn't know anyway other way to do it than the right way

Thanks !!!
I try very hard and don't take shortcuts. most of the time it pays off

Thanks again
J E CUSTOM

 

[puttnpurr]

I think dakota silencer
Has a cnc that allows them to thread without taking off barrel. $100 plus shipping

 

[rewiltshire]

.... bbbbbuuuuutttttt.... saying "I did it myself"....... lol
DIY is overrated- gonna put that on a T-shirt

Gotta laugh at that. But my DIY consist of loading the parts into my car, driving to my "smith", dropping the part off and waiting for him to call me. Little things I will do, but if I want a professional job done, I will leave it to the professional.

 

[IdahoCTD]

Like I said before, turn a snug-fit mandrel for the bolt raceway if you don't have one. Stick it in the receiver, lock it down, chuck it in a collet or set-tru chuck. Muzzle in a precision live center. Turn down/cut the tenon, put it in the steady. Cut the threads, crown it, and done. Can't be anything but concentric to the bore.

For some reason, working between centers- including chambering (which btw, is still done that way by McMillan, Kelbly's, USMC, and many others) is now frowned upon by the "experts".

With that method your assuming the bolt raceway is perpendicular to the chamber/bore and when your locking it down its not moving. That's not generally the case with factory guns. If you use a long stem indicator on just the muzzle end you know the bore is straight. Just because a barrel is turned between centers from the factory or from a aftermarket company doesn't mean the bore is centered anywhere else between those 2 points and the odds of it not being perfectly centered are way higher. Take a 27" blank and cut it to 24, 22, or 20" and see if its centered. How many factory actions have the threads and action face perfectly centered and square to the bore? Short answer is almost none. Add in a sandwiched recoil lug, like a Remington, that isn't parallel and your action is pointing a different direction from your barrel.

I would love to see you make a split, bolt together, bushing and turn it true in your set up. Then remove the barrel and put it between centers. Measure the bushing and see if it runs true. My bet is it doesn't, especial if you measure it in multiple spots on the bushing.

 

[25WSM]

Tobnpr I'm trying to follow what your saying because it's like one of the ways I do it. But how are you cutting threads and crown once you put it in the steady rest. You can't hold the work in the steady rest on the tennon and cut the threads on same such tennon. You can cut the threads while the muzzle is in the live center. But then you have nothing to run in the steady rest to cut the crown except threads. Please explain. The only way I see your way working is if you cut the tennon long enough to hold in the steady rest and cut the threads and crown. Then when your done there is a piece of tennon behind the threads that are going to show.
Shep

 

[25WSM]

If I have to do it that way I would cut the tennon and thread while it's in the live center then put thread protector on and make a truing pass on it. Then run the protector on the steady rest while cutting the crown. Still not as accurate as going in the headstock and using range rods or Gordy rods. If barrel is so short I need to take it off I would mount it in my 8 point spider that I use for action truing. It would then get dialed in with range rods.
Shep

 

[Andrew Cowling]

When I work on clients guns I let the gun tell me which is the best method of threading. My prefered method is to cut between centres as I know then that it is perfectly square to the bore.

I have recenly done a batch of them. As for factory barrels the outer profile isn't always concentric to the bore so removal and running between centres is the best option IF the barrel comes out easily. One I did recently the barrel refuced to budge and the shortened barrels profile was way off centre. Chucked the action in the 4 jaw and dialed it in with the live centre at the muzzle end. A pain in the arse job but a good result in the end.

I am building a rifle for my wife in 260 remington with a match barrel that I fitted and finished at 28 inches. Cerakoted in her favourite colour. I then decided to fit a muzzle brake. Being a round Savage Axis action (the rifle has been named and engraved 'Terminaxis') it was easy to chuck in the 3 jaw as the run out was less than .001" and over a 28 inch length at the live centre that is more than close enough to get a good square job.

Now my Ruger custom VT that I also fitted a 28 inch 30 calibre match barrel to was a different story. I didn't intend on fitting a muzzle brake when I built the rifle but since using it I have been leaning towards fitting them to help with muzzle jump. Especially since I will be shooting at 1 kilometre. Due to the action configuration it is near impossable to clamp it in a chuck so the barrel was removed and thread cut between centres. This rifle has been cerakoted in dark earth colour. My action wrench and barrel vice (I made both myself) didn't leave a single mark on the finish.

When I am build a new rifle from the start all threads are done between centres before the barrel is fitted to the action.

So each rifle and situation is different and I let the gun tell me what it needs. However, my prefered method is to remove and turn between centres as I believe that is the most accurate of all ways to do them.
Cheers
Andrew