Gunsmithing Threading barrel for silencer

[crumpmd]

Since I don't have range rods yet I set up between centers and cut these. It looks good and the silencer fits. Do you see any problems. Except for the dogs I think it looks ok.

Thanks to TCA4570 who supplied the Valinite thread cutting tool.

 

[JJones75]

Re: Threading barrel for silencer

As long as you know that your tail stock is dead nuts strait it should be fine , I've seen barrels threaded with a WAY less suitable setup that that and that shot fine.

Did you set it up between centers and see what the run out was on the OD before putting the steady rest on the barrel , it will likely have moved some as getting it to contact perfectly by eye would be luck at best.

One thing though is that your going to want to touch up the crown after you pull the live center out as it will likely have make some small inperfections on the lands.

One thing I would do is clock your tool post 90 deg to the left so tha you can cut on the other side of it ,this will allow you to get WAY closer to the steady rest and chck head later and would have eliminated the need for the follow rest on this job

 

[jasonk]

Re: Threading barrel for silencer

It's hard to tell in the pic (and I am no expert) but is there enough shoulder there for the suppressor to tighten against?

 

[Terry Cross]

Re: Threading barrel for silencer

Please proceed with caution as you try things out.
Per Jason's comment, if you are using a direct thread on suppressor, the shoulder that the suppressor tightens up against is of the utmost importance.

That shoulder is what will bring the suppressor into alignment with the bore (square to square)and is almost more important that the concentricity of your threads. The threads absolutely have to be true to the bore but that shoulder is what keeps things behaving in a safe fashion.

You always want as much barrel O.D. as possible behind the termination of your threads. The larger shoulder will always do a better job of squaring up your suppressor and will offer infinite advantages in keeping the suppressor tight/secure during firing.

If you are dead set on using that barrel contour, I would consider threading/machining a little further back and permanently mounting a collar for the suppressor to interact with. If you do so, machine the face of the collar once it is in place on the barrel to insure that it has the critical squareness you need.

Just my 2 cents.

Good luck,
TC

 

[crumpmd]

Re: Threading barrel for silencer

I was just curious about the set up. I appreciate the comments. This barrel will be used for practice on the lathe and discarded.

I checked the runout with a test indicator and got .0005 so I think that is good.

The live center was in the way of having the tool on the other side of the post.

When I get range rods I will try this in the 4 jaw.

I appreciate your insight Terry .

 

[wnroscoe]

Re: Threading barrel for silencer

I'm guessing that’s a sendero taper barrel, .835" at the muzzle. Are the threads 5/8" x 24 (.625" x 24 tpi) if so, the shoulder looks too small but, if the suppressor fits, that’s it. I agree with Terry, the muzzle threads need to be 100% concentric to the bore and the shoulder needs to be perpendicular to the bore. It's all about avoiding a baffle strike.

Just out of curiosity, how was the OD of the barrel running when the steady rest rollers were adjusted to just make contact? Did it look to have a skipping movement to any of the rollers?

Research the deep hole drilling or the gun drilling process to understand what the bore is actually doing.

Touch up your crown before you take the barrel out of the lathe. Congrats, looks good. Where you nervous

 

[wnroscoe]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crumpmd</div><div class="ubbcode-body"> When I get range rods I will try this in the 4 jaw. </div></div>

Life will be grand at that point. Dont forget extra bushings.

 

[jasonk]

Re: Threading barrel for silencer

I'd like to add that I'm very jealous, I want a lathe badly, but my wife insists on being able to use the garage as a place to park cars

Oh well, for now I'll have to keep all my fingers and continue to be jealous.

Keep posting pictures for me crumpmd.

 

[257speed]

Re: Threading barrel for silencer

You live in sunny vancouver!!!! Garages are meant to be shops! Lay down the Man law my friend! And let me know how it works out for ya

 

[300sniper]

Re: Threading barrel for silencer

if it were me and my self taught and still learning self, i'd skip the steady rest and follower rest during the threading portion. you're working so close to the support of the center that there shouldn't be any need for either one of them. once you have turned and threaded the muzzle, the steady can be placed on the threads, the center removed and the muzzle crown recut.

i don't like the idea of a steady/follower rest riding on an untrued od fo the barrel.

 

[shepherm]

Re: Threading barrel for silencer

What model Jet lathe is that? I just got the BDB-1340 and been playing around on it.

 

[Rafael]

Re: Threading barrel for silencer

crumpmd;
I needed a driver for my dogs as well and wound up just drilling some holes in a scrap piece of angle-iron and bolted it to my plate. Works fine for all the dogs I have.

That's creative use of two of them!

 

[AKA-Spook]

Re: Threading barrel for silencer

Do it through the headstock and find the center with your indicator just like when you chamber. Leave the steady and follow in the cabinet. Spin your toolpost so that your threading from the left side...That way you can cut,thread and crown without involving the tailstock at all. ( which ,may or may not be conc with the centerline of your spindle bore)

 

[crumpmd]

Re: Threading barrel for silencer

Why thread from the left?

 

[300sniper]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crumpmd</div><div class="ubbcode-body">Why thread from the left? </div></div>

i think he is suggesting having the tool on the left side of the tool post so you can have only the amount needed to work sticking out of the chuck.

in my opinion, through the headstock and indicating in two places is the best method. if you can't do that for some reason and had to do it with a center, the way i mentioned earlier would be my next choice.

edit: if there is some reason you have to use a steady rest, you need to turn a section so the rest is riding on a surface that is true to the bore. you may not have been able to measure any runout near the steady rest because it is holding the work. that does not mean the bore is concentric. in fact, i'd find it very hard to believe that the od of the barrel where you have your steady is even close to concentric to the bore at the muzzle. the barrel is flexible and i think you are forcing it to do things that it doesn't need to be doing with your set up.

 

[TCA4570]

Re: Threading barrel for silencer

I didn't know you might use it on that side.
Shiny surfaces are flatter and staighter.
Thought you were going to use it on the left, and needed clearance.
Cut to fit your toolpost.

Need to start cutting with some kind of oil.

Better finish.

 

[TCA4570]

Re: Threading barrel for silencer

Real cool, old school, and compound is right for threading.
Threading from the left may be easier for some.
Upside down and backwards.
Id, Od, Righty, Lefty?

 

[AKA-Spook]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crumpmd</div><div class="ubbcode-body">Why thread from the left? </div></div>

Nothing "behind" your cut to crash into the jaws as you're transfixed on the threader heading for the shoulder/relief cut. I thread everything from the left and when I come up to a shoulder I back out the threader and shut of the lathe. I got in the habit when I started rebarreling metrics and couldnt disengage the half nut... now I thread everything without disengaging.

 

[BLAWTON]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AKA-Spook</div><div class="ubbcode-body">Do it through the headstock and find the center with your indicator just like when you chamber. Leave the steady and follow in the cabinet. Spin your toolpost so that your threading from the left side...That way you can cut,thread and crown without involving the tailstock at all. ( which ,may or may not be conc with the centerline of your spindle bore) </div></div>

My thoughts exactly. I know that this will stir the pot a bit but range rods suck! I could never bring myself to use something that could be anything but perfect. I use a interrapid with a 3" needle or stylus on it for all my center. Its all you need. Yes i do use range rods but only to find the correct size pilot i use after i start the hole in the chamber and true it up with a boring bar. I find the perfect fit where the neck is gonna be at when im close to finish depth with the chamber reamer.

 

[crumpmd]

Re: Threading barrel for silencer

I am sorry spook. I had a moment there. I thought you were saying to thread from the left side of the barrel, threading from the other side towards yourself. lol

I put the tool on the right side of the post in the pictures above because the live center is so fat I could not get the post close enough with the tool on the left.

I appreciate all the input.

Thinking about the setup in light of the comments I would have to agree that threading right next to the live center would obviate the need for the steady rest and follower.

I am going to order indicator rods from Pacific tool to work on my new rock creek barrels. I have a new .308 and 6.5mm and will want to use the 6.5 for this year hunting season. I am making a youth size rifle for my boys. I plan to use a Rem 700 action and this new barrel and chamber in 6.5x47 Lapua and cut to 20 inch length and thread for a silencer. I plan on doing those operations in a 4-jaw chuck and not between centers.

 

[Hateca]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crumpmd</div><div class="ubbcode-body">

Thinking about the setup in light of the comments I would have to agree that threading right next to the live center would obviate the need for the steady rest and follower.

I am going to order indicator rods from Pacific tool to work on my new rock creek barrels. I have a new .308 and 6.5mm and will want to use the 6.5 for this year hunting season. I am making a youth size rifle for my boys. I plan to use a Rem 700 action and this new barrel and chamber in 6.5x47 Lapua and cut to 20 inch length and thread for a silencer. I plan on doing those operations in a 4-jaw chuck and not between centers. </div></div>

Build a spider for the lathe spindle bore if you're going to do it that way (is your headstock short enough for 20" barrel?) or the outcome may not be what you anticipated.

 

[Redmist]

Re: Threading barrel for silencer

Never been 100% happy with doing anything bettween centres.


Thats why I do all my screwcutting / chambering / barrel work thru the headstock.

Build a spider for the outboard side, get some range rods and you will be 100% sure of your concentricity and set up.

Aside from this, using centres (in the way you have set up) will mark the barrel - this is not a criticism just observation.

 

[crumpmd]

Re: Threading barrel for silencer

This lathe has an outboard spider standard. It is the Grizzly 4003G.

The range and indicator rods, bushings ect... are on order from Pacific tool and gauge and ought to be here next week.

True enough the distance throught he spindle bore with a 4-jaw chuck is 21.5 inches. I have ordered a spider to replace the 4-jaw and that will give 17 inches. Ought to be GTG.

 

[wnroscoe]

Re: Threading barrel for silencer

Take a piece of bar stock 8" to 10" long and drill/bore a hole 1.5" deep with an ID of 1.006" to 1.0085". Bore another hole from the entrance of the initial bore to an ID of 1.0625" for the first .500". Thread the 1.006" hole to 16 TPI to just shy of the bottom. Be careful as not to crash your tool. What you'll have is an extension that barrels can be screwed into. Muzzle work can then be performed on barrels that are shorter than 22" but not shorter than 16"

Thread the other end 1.0625" x 18tpi for barrels on some of the customs.

 

[mr2tuckb]

Re: Threading barrel for silencer

Did you cut those threads straight depth or slant depth?

 

[crumpmd]

Re: Threading barrel for silencer

They are cut at a 29.5 degree angle infeed with a 60 degree carbide insert cutter and Mobil 1 thread cutting oil. I was only using 70 rpm speed though, that may be a little slow. When I get more confident I will probably use 200 most of the time.

I hope that answers your question.

 

[JJones75]

Re: Threading barrel for silencer

The carbide will certainly cut better at higher RMP.

Did you get a chance to measure the dovetail on that tool post?

 

[crumpmd]

Re: Threading barrel for silencer

Nope, but I found out it is equivalent to a BXA series if that tells you anything.
Thanks!

 

[skog]

Re: Threading barrel for silencer

WOW!! This is why I love this forum. Do you turn the OD to be concentric to the bore of the so if you screw the barrel in the extension you can center the barrel off the OD of the extension or do you run a long range into each end of the barrel to center it?
thanks
skog

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Take a piece of bar stock 8" to 10" long and drill/bore a hole 1.5" deep with an ID of 1.006" to 1.0085". Bore another hole from the entrance of the initial bore to an ID of 1.0625" for the first .500". Thread the 1.006" hole to 16 TPI to just shy of the bottom. Be careful as not to crash your tool. What you'll have is an extension that barrels can be screwed into. Muzzle work can then be performed on barrels that are shorter than 22" but not shorter than 16"

Thread the other end 1.0625" x 18tpi for barrels on some of the customs. </div></div>

 

[300sniper]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: skog</div><div class="ubbcode-body">WOW!! This is why I love this forum. Do you turn the OD to be concentric to the bore of the so if you screw the barrel in the extension you can center the barrel off the OD of the extension or do you run a long range into each end of the barrel to center it?
thanks
skog

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Take a piece of bar stock 8" to 10" long and drill/bore a hole 1.5" deep with an ID of 1.006" to 1.0085". Bore another hole from the entrance of the initial bore to an ID of 1.0625" for the first .500". Thread the 1.006" hole to 16 TPI to just shy of the bottom. Be careful as not to crash your tool. What you'll have is an extension that barrels can be screwed into. Muzzle work can then be performed on barrels that are shorter than 22" but not shorter than 16"

Thread the other end 1.0625" x 18tpi for barrels on some of the customs. </div></div> </div></div>

the extension would be used at the chamber end for doing muzzle work on a short barrel. the extension is used to effectively lengthen the barrel so the spider can hold it. it does not need to be concentric to anything really. a range rod would still be used at the muzzle end with two indicators.

 

[wnroscoe]

Re: Threading barrel for silencer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body">the extension would be used at the chamber end for doing muzzle work on a short barrel. the extension is used to effectively lengthen the barrel so the spider can hold it. it does not need to be concentric to anything really. a range rod would still be used at the muzzle end with two indicators. </div></div>

Yea, what he said.