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Developing my gun building skills: Turning barrel shank threads **Now 5/8 x 24 too!** Login/Join 
Yeah, that M14 video guy...
Picture of benny6
posted
An old machinist friend of mine once said: "If you want to be a successful gun builder, don't turn down any work."

I've been working on expanding my customer base to those outside of the M14 and M1 Garand world and I've been working on other skills that appeal to the long range bolt crowd. One of those skills is being able to custom install a contoured barrel blank onto a bolt action rifle.

One of my customers has asked me to install two Proof Research barrels onto Remington CSR barrel extensions. He knows I've never done this before and is willing to wait while I train myself to do this kind of work.

Over the last year, I've bought all kinds of tooling, including carbide turning/facing tools and bits as well as carbide boring bars and inserts and external/internal carbide threading and grooving tools. I spent a lot of time getting my lathe in order a couple of weeks ago in preparation for this work. Here's the thread I posted on my results.
https://www.hobby-machinist.co...hews-pm1236t.110289/

At the end of the day, I was able to get my lathe aligned to within 0.0004" over the span of a 15 inch cut. So over the span of 15 inches, my lathe will cut a steel bar to within less than half a thousandth of taper. I got some advice from Frank at Bartlein barrels and he said my setup was more than adequate to do everything I can on that lathe.

He was gracious enough to send me some out of spec barrel blanks to practice barrel threading on. After three attempts to cut threads, I finally got it! My first attempt was foiled by a stupid mistake. Instead of cutting 16 TPI, I set to my lathe to cut 18 TPI. The threads were beautiful, but the wrong pitch! I practiced my second attempt on a cutoff M14 heavy barrel section and made a couple of goofs with my cross slide drifting off target and an error engaging the half-nut which bothched some of the threads. I was still able to produce a thread which allowed the extension to easily thread on, but the threads are way too small and there's a lot of slop.





After making those goofs, I formulated a plan and cut off the section of the Bartlein barrel with the wrong thread pitch and started over. At 1 AM last night I had nearly got it. I still wasn't able to thread the barrel extension on because the threads weren't cut deep enough yet.

In this picture was a take-off CSR barrel, the Bartlein barrel that I was working on and the cutoff barrel section from the M14.




I realigned the barrel into the lathe this afternoon and managed to pick up the threads with the thread cutting insert. I gauged the threads with a 3-wire thread gauge set and cut until they matched the thread diameter of the take-off barrel. I was now able to thread the insert on about a turn before it bound up, so I chased the threads a few times and was finally able to thread the extension on by hand all the way.

Here are the threads after the final cut and cleanup...


Barrel extension fully screwed on hand tight...


The bolt head had enough clearance to insert and rotate locked


Training barrel and take-off barrel.


Anyway, the next step will be muzzle threading to 5/8-24.

Thanks for looking!

Tony.

This message has been edited. Last edited by: benny6,


Owner, TonyBen, LLC, Type-07 FFL
www.tonybenm14.com (Site under construction).
e-mail: tonyben@tonybenm14.com
 
Posts: 5335 | Location: Auburndale, FL | Registered: February 13, 2001Reply With QuoteReport This Post
Loves His Wife
Picture of BRL
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I love to see a craftsman at work, no matter what the trade. To my untrained eye that looks beautiful. I can imagine the sense of satisfaction when you get it dialed in.

Your customer’s confidence in your ability to get this done speaks volumes for your potential.



I am not BIPOLAR. I don't even like bears.


 
Posts: 12925 | Location: Western WI | Registered: January 05, 2009Reply With QuoteReport This Post
Prepared for the Worst, Providing the Best
Picture of 92fstech
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Good stuff! Thanks for posting your process. I know next to nothing about machining but I enjoy the bits and pieces I can learn from reading these threads.
 
Posts: 8187 | Location: In the Cornfields | Registered: May 25, 2006Reply With QuoteReport This Post
quarter MOA visionary
Picture of smschulz
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Looks like a great start.
Wish I had the tools, space, metalworking experience to do the same but alas I don't. Frown

With all the new actions with some pretty precise pre-fit options, I can imagine some of this work could be diminishing.

I hope not as it is a true skill that I admire .

I have Rem 700 (308) that has a decent 5R barrel that still is quite good but recently did a Terminus (6.5CM) with a Proof pre-fit that went together so easily and shoots with spectacular fashion.

Keep up the good work!
 
Posts: 22735 | Location: Houston, TX | Registered: June 11, 2006Reply With QuoteReport This Post
Yeah, that M14 video guy...
Picture of benny6
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Thanks for the encouraging words, my friends!

quote:
Originally posted by smschulz:
Looks like a great start.
Wish I had the tools, space, metalworking experience to do the same but alas I don't. Frown

With all the new actions with some pretty precise pre-fit options, I can imagine some of this work could be diminishing.

I hope not as it is a true skill that I admire .

I have Rem 700 (308) that has a decent 5R barrel that still is quite good but recently did a Terminus (6.5CM) with a Proof pre-fit that went together so easily and shoots with spectacular fashion.

Keep up the good work!


I think there will always be room for this kind of work in the bolt gun crowd, as well as the older 03 Springfield and Mauser crowd.

I read a comment from Frank at Bartlein Barrels last week and he states that they WILL NOT make a pre-fit barrel. There are too many variables at play.

Even with the last run of M14 barrels, he didn't cut a short chamber, nor cut a crown. Each M14 barrel needs a full chamber cut and about 3/4 of an inch cut off the muzzle and crowned.

Tony.


Owner, TonyBen, LLC, Type-07 FFL
www.tonybenm14.com (Site under construction).
e-mail: tonyben@tonybenm14.com
 
Posts: 5335 | Location: Auburndale, FL | Registered: February 13, 2001Reply With QuoteReport This Post
Yeah, that M14 video guy...
Picture of benny6
posted Hide Post
I had a Savage take-off barrel that I've used before for chamber cutting practice and I used the muzzle end to practice some 5/8-24 threads. These came out much better than my receiver threads.

I flipped my cutter over and threaded from left to right with the lathe in reverse. Everything came out really nice and I polished up the threads with a needle file, scotch brite and a wire brush. The tops of the thread had some burrs so I skimmed the top of the threads with my turning bit. My barrel thread protector fit on very smooth and not too loose. I haven't gauged the threads yet but they should be in spec.













Tony.


Owner, TonyBen, LLC, Type-07 FFL
www.tonybenm14.com (Site under construction).
e-mail: tonyben@tonybenm14.com
 
Posts: 5335 | Location: Auburndale, FL | Registered: February 13, 2001Reply With QuoteReport This Post
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