Buch chuck or 4 jaw when using a steady rest?

[AccelR8]

I certainly have not chambered as many barrels as many people here, but it is my humble opinion that when you get a barrel blank, no matter whom the supplier, you cannot assume that the cylinder portion of the barrel will be concentric with the bore. Chances are it'll be close but not as close as you might like. I run my steady rest on the tenon, even after my threads have been cut, and I've not had any trouble from wear of the steady rest fingers during a chambering job. I do pay close attention though. I don't set them tight, I initially set up with .002 shim stock between the fingers and the tenon, then carefully remove the shims and take out the final clearance by feel.

I think if you didn't want to run on the threaded tenon you should do a clean-up cut on the cylinder portion while the barrel is set up in your centers before you set it in the steady rest.

If you don't want to do that, or otherwise mess with the barrel's profile or finish...I've done the following but it's not my idea. I read it years ago and want to attribute it to Ed Shilen, and I want to say it's in the “130 page PDF of different chambering methods” linked to in the Advanced Gunsmithing and Engineering forum. But I'm not certain about either of those. Anyway, an aluminum cylinder is bored with a hole to fit around the barrel with some clearance. It is affixed to the barrel with polyester auto body filler. Like Bondo. With the barrel between centers, the OD of the cylinder is cut and will be concentric with the centers. The steady then runs on the aluminum cylinder. When the job is done, heat from a heat gun takes the Bondo off. I've done this on blued, finished barrels and not left a mark.

 

[tobnpr]

Please re-read my post.

If the breech end has a straight cylinder or decent taper I will true several inches, and let the steady ride ahead of the actual tenon.

Guys, I clearly said I would set the breech cylinder in the steady only after truing.
If it's a bull barrel or one with little taper that can't be trued/turned off in a few inches of length it's a no-brainer . Steady goes on the tenon.

Clearly, closer to the center the better. But half an inch (provided I am able to true a short section ahead of the tenon) is inconsequential IMO- and I prefer that route over the steady riding the threads because of possibility of wear/runout.

 

[AccelR8]

tobnpr, for the record I was not replying to or even thinking about anything you posted, my comments were prompted by something someone else posted.

 

[ridgeway]

I made a cat head that runs in the steady rest with 4 brass tipped set screws to dial in the barrel easily.

I'm in process of doing a 15-16" XP barrel. I made a threaded extension to reach my outboard spider.

Many ways of doing think...be creative...

 

[shortgrass]

Many ways of doing think...be creative...

Ya',, right! Thinking for ones self has become a thing of the past for many. Now, just go to the interdnet and ask "how"......

 

[Cloudrepair]

First is Setup figure what you want to accomplish then you may be able to see what is needed to do it. if you do have a machining background then you may see.
It can be hard to see what needs to be seen

 

[Cloudrepair]

If you can see what needs to be done then you may be able to see what you are asking it doesn't matter how you hold it if you can hold it the way it needs be held

 

[bored184]

A lot of good information, thank you guys. I'll probably have more questions as I read through it a couple of times.

The lathe in question is a SouthBend turnado 17. Probably a bit large for barrel work but it's my father's and it's what I have access to at the moment.

 

[Dusty Stevens]

The lathe in question is a SouthBend turnado 17. Probably a bit large for barrel work but it's my father's and it's what I have access to at the moment.

Down here in the south thats how we say “tornado” when we’re on the news describing what happened to the trailer park.

 

[bored184]

Down here in the south thats how we say “tornado” when we’re on the news describing what happened to the trailer park.

Haha...I guess I spelled it wrong its "Turn-Nado". Its not a bad lathe but I wish it was a bit smaller to learn on.

 

[geo.ulrich]

Down here in the south thats how we say “tornado” when we’re on the news describing what happened to the trailer park.

Dusty, thats funny we call it an improvement...

 

[Dusty Stevens]

Remodeling

 

[bored184]

After many thought experiments I have a few more questions. When using centers for the sacrificial cuts and threading are you assuming that the bore was drilled perfectly strait through the blank? That seems like a pretty big assumption and could leave you with an offset chamber depending if there are in dips or curves in the bore.

I like the idea of using Vipers jig but I will have to save my pennies for that. Using his jig, I think, would allow me to dial in on the chamber end using range rods and I will have a better match up between the chamber and bore.

Please let me know if I am out in left field on this. I don't have much stock to play with so before I start whacking on worn out barrels for practice I want to make sure I have my ducks lined up first.

 

[butchlambert]

After many thought experiments I have a few more questions. When using centers for the sacrificial cuts and threading are you assuming that the bore was drilled perfectly strait through the blank? That seems like a pretty big assumption and could leave you with an offset chamber depending if there are in dips or curves in the bore.

I like the idea of using Vipers jig but I will have to save my pennies for that. Using his jig, I think, would allow me to dial in on the chamber end using range rods and I will have a better match up between the chamber and bore.

Please let me know if I am out in left field on this. I don't have much stock to play with so before I start whacking on worn out barrels for practice I want to make sure I have my ducks lined up first.

How would a range rod or Gordy rod make a bore straight?

 

[AccelR8]

You are not out in left field. You re thinking correctly. I think one key element is how you hold the reamer.

I think with today's technology and modern gun drills, reamers and hones barrel makers are probably giving us barrels that are pretty good. On the other hand I think the best gunsmiths will always check a barrel for straightness, among other things, before going ahead with it.

Let me qualify my following comments; I'm not building bench rest guns. I might be happy with ½ MOA and thrilled with ¼ MOA but I'm not trying to put 5 shots through 1 hole at 300 yards! My best build to date is a consistent .3 MOA gun (that's point-3 MOA, not 3 MOA ).

With a steady rest, I use a Bald Eagle reamer holder which allows the reamer to follow the bore no matter what. It “floats” in all directions. When chambering I know my tenon is running is concentric, my muzzle is running true (either on a center or in a four jaw) and no matter where that bore goes my reamer has no choice but to follow it. I do not pre-drill. When finished I can detect no measurable run out between the chamber body and neck and the barrel throat area, for sure less than a tenth.

I use a very slow, careful and gentle approach. I'm sure if you just cranked that reamer in there even with the floating holder you'd create problems. You have to "let" the reamer and holder do what you want it to do. I'm sure most folks here would laugh at how long I spend on a chambering job!

There are all kinds of reamer holders and not all of them float in every plane. I think some of them used while chambering in a steady, you may wind up with an oversize chamber or a misaligned chamber. Or both. Those reamer holders really shine when the bore is dialed in with spiders at both ends...which may be the best way to chamber, assuming the person doing it has both the equipment and skill required.

 

[butchlambert]

I don't use a reamer holder. My reamer will follow my taper bored hole. I push the reamer inorder that nothing influences it except the bored hole.

 

[ridgeway]

I used to push Butch but once I got a JGS reamer holder and set up with high Psi oil flush...i never looked back!

 

[sdean]

How would a range rod or Gordy rod make a bore straight?

I see winning barrels chambered many different ways. I think there is something else common to winning barrels other than the shooter. You are right nothing will make the bore straight.

 

[B Nettesheim]

Keep in mind that almost no barrel is straight or concentric with the od
If using a steady you are a little limited in proper alignment with the spindle center but you can definitely chamber it just not perfect in my opinion. Use what you have and don’t get discouraged.
Align the id of the barrel with the spindle and re cut your 60 degree center on the chamber end
Flip it around sticking out a couple inches of the muzzle end from the chuck. Align the id of the bore with the spindle, now turn the od of the barrel for an inch or so.
Flip it again so you are chucking on the very end of the muzzle.
Assuming your tailstock is very centered with the spindle insert your center into your newly created center that is alinged with the bore.
On the chuck end zero your indicator on the od of the barrel which should be concentric with the id.
You are pretty close to turning between centers with what you have, but keep in mind you are turning a banana.
Now turn a portion of your barrel od for your steady to ride on, keep it close to your tailstock. In my experience this is the best way to get aligned with the spindle when using a steady.
Your tailstock alignment is your weak link in this set up and getting it aligned is another article in itself.
BN

 

[butchlambert]

Keep in mind that almost no barrel is straight or concentric with the od
If using a steady you are a little limited in proper alignment with the spindle center but you can definitely chamber it just not perfect in my opinion. Use what you have and don’t get discouraged.
Align the id of the barrel with the spindle and re cut your 60 degree center on the chamber end
Flip it around sticking out a couple inches of the muzzle end from the chuck. Align the id of the bore with the spindle, now turn the od of the barrel for an inch or so.
Flip it again so you are chucking on the very end of the muzzle.
Assuming your tailstock is very centered with the spindle insert your center into your newly created center that is alinged with the bore.
On the chuck end zero your indicator on the od of the barrel which should be concentric with the id.
You are pretty close to turning between centers with what you have, but keep in mind you are turning a banana.
Now turn a portion of your barrel od for your steady to ride on, keep it close to your tailstock. In my experience this is the best way to get aligned with the spindle when using a steady.
Your tailstock alignment is your weak link in this set up and getting it aligned is another article in itself.
BN

Turning a banana? How do you know that? Could it actually be a bore running in a helix or other directions?