Threading between centers question.

I have a 10/22 Barrel I want to cut down and thread. It won't fit through my headstock so between centers it is and I have a few questions about it.

#1 Will the dead center in the headstock damage the chamber?

#2 can I run a dog off the chuck? (My lathe has no headstock taper so I will be turning a dead center in the chuck)

#3 Dead center for the muzzle? Or is a live adequate?

#4 Forgot to add... Will the centers still be "true" without the 60 degree center drill into the barrel?

This is more or less for the fact I want to thread the barrel. I plan to build a can eventually just haven't got the paper work started. Thanks for the help!




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HELP the situation. MAKE a tool that fits the chamber and has its OWN center "hole"

And MAKE a tool that fits the muzzle bore and has its own center "hole"

I think you would better to hold end of barrel in four jaw and use a center rest. , than threading between centers

Claude Wright said:

I think you would better to hold end of barrel in four jaw and use a center rest. , than threading between centers

Click to expand...

Claude

What should a fellow do if the bore isn't true with the barrel OD, run the steady on some sort of sleeve or cat's head?

CalG said:

Claude

What should a fellow do if the bore isn't true with the barrel OD, run the steady on some sort of sleeve or cat's head?

Click to expand...

This never occurred to me, always assumed they did both in one setup. How does one indicate over the rifling of a used barrel with any certainty? Makes me wonder about chamber concentricity as well, if it'd be a good reference.

Johnoder I like the idea of making piloted plugs with centers in them. My only concern is with them being on .22 cal, how much side load could they sustain from threading?


Claude I have a four jaw but my steady is rather crummy. I've been meaning to re-do it but haven't gotten around to it. How could I indicate the chamber while in a four jaw and how would I indicate the muzzle? Would I be best off building a 4 jaw steady? Or as calG said run a cats head inside my steady?


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Type of lathe might help. They do make brass piece that centers in the muzzle end and goes over a live or dead center. Brownells carries them . I got a set off of EBay.

A cat's head in your steady is going to be the best way of getting the threads and crown all in one setup. You can then re-indicate off the OD of the barrel to spin up a thread protector that matches the barrel OD.

An alternative is to put a bushing around the barrel near the muzzle, cut a 60-deg center pilot in the muzzle, and set the muzzle in a live center. Then machine the bushing down and put it in your steady. There are a variety of putties and adhesives that can help the bushing stick without getting too fussy with the fit.

In either case, once the muzzle end is in the steady, use a rod in the bore, or a long-reach indicator to indicate off the bore at the muzzle, and a few inches in. Tweak the 4-jaw as needed to straighten things out at the muzzle end. This isn't needed for a muzzle brake, but given that this is a 22LR, I assume you're threading for a can, and concentricity is critical for not only preventing baffle strikes, but for accuracy. Once the threading is done, if you're using the rod method, you can put the rod back in the bore through the suppressor, and verify that it's nicely centered in the end-cap.

Hardened said:

This never occurred to me

Click to expand...

Then why are you posting in the gunsmithing forum? That's some basic stuff, there.

OP:
Given that the 10/22 has a barrel extension (I may be forgetting the right term) that slips into the receiver, it should be assumed to be concentric to the chamber. I would double check that before trusting it. You could use that in the 4-jaw if you cannot reach a rod in the chamber-end bore to dial that in directly. This is not ideal (kind of a hack and you're lucky if they're concentric), but I don't see a lot of info on your tooling and lathe so I am taking a guess. Ideally, one method is dialing in both ends on rods in the bore.

4 jaw chuck, figure out a way to center the /bore/ (whether using a proven-concentric feature or range rod in the bore... preferably range rod) and then the live center with a brass crown-saver (google it and buy/make them) at the muzzle.

Now... a live center in the muzzle will not GUARANTEE you have centered on the bore AXIS at the end (bullet path)... it will only center on the circle made by the muzzle - a point, not a vector. It may be close enough... maybe not. I would suggest you hold the muzzle in the rest and dial in on a range rod. There are a couple good methods of dialing in on the muzzle end - I've seen the topic come up here on PracticalMachinist many times.

I've never done muzzle work between centers. Not saying it can't be done. It's an interesting challenge but I think it would be wise to make the proper tooling to outfit your lathe to simulate a better method. There's threads I've seen with Speerchucker and 300sniper and other folk more experienced in barrel work who have uploaded pictures of their various setups - you might seek them out to get a better idea of what some of us are talking about. Pictures are better than words. Especially me - sometimes I don't words-so-good.

Oh...

and start the paperwork now. You need the stamp before you even begin making the first part, technically. So get the paperwork in now and you'll have time to figure out design and get materials so you're ready when it comes back in. You also don't have that shitty feeling of having plan and idea, but having to shelf it for 4-10 months to wait on paperwork.

So just do it now and get it moving.

My lathe is an old Sheldon 9x42. The rare model, it's old but still does decent work. I have a enco 8x40 mill as well. No crazy fancy tooling, I still grind HSS for the lathe. I have a needle indicator but I wouldn't consider it "long reach" it may be 1 inch long. I don't have any range rods. Not sure where to really find them or I'm calling them the wrong name.

I should have stated earlier that I have means of fixing the crown outside of the lathe. So if I have a center in the bore its all good.

Sounds like I need to fix my steady and build a cats head for it. I do have a factory 10/22 barrel laying around. Maybe I'll try it between centers and see how it does. Not sure how to check it for concentricity though without a can and an alignment rod.

Thanks for the tips guys. I'm self taught on all this equipment so im by no means a machinist but I'm getting fairly proficient thanks to PM and you fellas.


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I always ordered my important shit straight from Pacific Tool & Gage. They'll have range rods you need.

When I was first starting out with gunsmithing (though I was a machinist prior) my mentor-of-the-trade gave me advise and also pointed me at some good stuff on a few forums. There's snipershide, weaponsguild, silencertalk, and a bunch of others. If you want to know about doing barrel work right, then your long-range specialists will typically have that sorted out since "good enough" is not good enough for "accuracy assholes" - some of them are in the business of making it to be the best. So you can get good advice and often times pictures (I like pictures) there.

I'm on weapons guild and the hide. I wish the guild would go to a phone format as I don't have a computer. I'm in The process of building a shop at my house and once that's done I plan to buy a nice grizzly Gunsmith lathe. I like the challenge of using old shit and the obstacles it creates. But it has its limitations. The best part is when I crash it, I'm not tearing up new expensive shit. In the same sense, when I crash it, I'm hurting a lathe that only made for a few years and no one has the parts to fix :/. I'm a welder by trade and we have the mentality at times to say "F it and get a bigger hammer" so I've been working on not doing that when it comes to my machining.

Ima grab an alignment rod from PTG and practice on that scrap barrel. I'll be sure to post my results on here. Thanks again for all the help.


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So here's a question. What's the difference between a grizzly rod and a range rod? And what bushings is PTG talking about?

I was under the impression that they were just a precision ground rod with a slight taper that slides in until snug and indicate off of that? Am I wrong?


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I always used caliber-specific rods, myself. I can't honestly tell you if it's best or if there's better - I just know that was the first way I was taught, it worked, and so I continued.

Grizzly rods are made to be accepted by a bushing that fits in the bore rather than the rod sliding into the bore itself. There is discussion on which is better... which is more repeatable... which is more 'true' but... reality is over my head as I never experimented to determine which was the better truth and the rods method I used got me where I wanted every time.

ajdemar215 said:

So here's a question. What's the difference between a grizzly rod and a range rod? And what bushings is PTG talking about?

I was under the impression that they were just a precision ground rod with a slight taper that slides in until snug and indicate off of that? Am I wrong?


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Click to expand...

A range rod is close to what you are describing. It is very slightly tapered, but has a bushing on the end that can be swapped out to get a super precision fit to the bore. The bushing end goes into the bore about an inch and a half or so before the tapered part grabs. Then you dial in the rod in two planes to ensure concentricity with the bore.

A grizzly rod is a different beast altogether and a bit hard to explain. The rod itself is chucked into the tailstock and the bushing end is moved back and forth in the bore using the tailstock quill. It allows for more control over where in the bore the bushing resides so it is supposedly better than a range rod when you want to precisely line up to where the throat of your cartridge will end up when say reaming a chamber. It does require a very precise tailstock and quill alignment though.

I don't have any grizzly rods and have never used them myself. There's a Gordy Gritters video I've seen where he uses one. I'll see if I can find it and pull a clip or two from the video.

Edit: Added the clip from Gordy Gritters. This is from a copyrighted video and this clip is used under "Fair Use" clause. If the link fails, it probably means that YouTube dowsn't agree with my claim to fair use. Anyway, buy the video HERE, it's informative.

Gritters Grizzly Rod Clip - YouTube

Here's how I set up for a range rod:

Range rods/grizzly rods are ok and do what they're supposed to do. Invest in a long stem Interapid indicator and indicate directly off the bore if you can afford it. You can get either a .0001 indicator and put a long stem on it (from long Island indicator or interapid) or the already made .0005 indicator. Doubling the length of the stem double the graduations. So if you double the stem a tenth indicator will read 2 tenths every graduation now.

I also have a mitutoyo indicator I use as well which I actually like better. It's a little cheaper and I put a longer stem. The resistance on the stem is nicer than the Interapid. It's model 513-504 and I have the 2" or so stem on it. Works great and you don't need different rods and bushings.

Mitutoyo Dial Test Indicator, Vert, to .1 In 513-54 | Zoro.com

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Forgot to add the mitutoyo fits nicely inside the chamber when you pre-drill/bore a barrel before reaming the chamber due to its skinny cylindrical shape.

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Claude Wright said:

I think you would better to hold end of barrel in four jaw and use a center rest. , than threading between centers

Click to expand...

Why? Between centers is just that. If you don't want to have it concentric to the bore do it this way.

Jerry said:

Why? Between centers is just that. If you don't want to have it concentric to the bore do it this way.

Click to expand...

Jerry have you threaded between centers?


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