Gunsmithing Chambering a barrel through the headstock?

[acebanana]

Never have even touched a lathe before so forgive me if I sound stupid.

How far can a barrel stick out of the headstock/spider/dohicky unsupported when chambering? Reason I ask is if say your spindle bore is only 1" but your chambering a barrel with say a Rem #3 contour where the barrel doesn't taper down to under 1" until after like 4" from the face of the tenon, can that portion of the barrel thats >1" stick out that far? Would it be better to used a steady rest to support it? I saw someone talking about chambering between centers, is that because he just couldn't fit any of the barrel at all through the spindle bore, or is there another reason?

Thanks!

 

[crumpmd]

Yes. If someone is chambering a rifle barrel between centers using a steady rest I would assume it is because he lacks a large bore headstock. Before I bought a lathe and got into this for myself I had a gunsmith cut down a barrel and thread and recrown the muzzle. Before this operation it would shoot all the bullets through one hole. Afterwards it would not. I did not get a baffle strike on my silencer so it was not too far off. But after I got my lathe I was able to shorten a bit more, cut the threads true to the bore at the muzzel and recut the crown and I am back to where it was. He used the technique of running between centers and a steadyrest. It ruined my cerakote, left a steadyrest ring.
I have chambered 5 rifles now through the headstock and they all shoot sub MOA. If I can do it then any monkey with the right equipment........

 

[jrm850]

If you are confident your lathe chuck will grip the barrel well on that steep shoulder angle you could true everything up how you like it, take a light cut on the exterior for a bearing surface that is concentric with your setup, and use your steady rest in a kind of hybrid through the headstock method. I definitely would not try to thread without some support closer to the business at hand, especially with a sporter taper.

 

[microsuck]

To answer your question, best practice is do not allow more than 2.5x the part diameter to stick out. So if you have a 1.25" barrel blank, 3" is the max you would want unsupported.

But if your chuck is making contact where its only 1", then 2.5" is your max.

 

[acebanana]

Alright thanks guys, I guess basically what I was getting at was how one could mickey mouse around using a lathe with a 1" spindle bore to chamber barrels. So far it seems like that isn't going to be the best idea ever.

So how long is a typical "spider" (Im assuming I'm using this term correctly) that can hold barrels/actions? If the spider isn't going through the spindle bore could I just make a 4-5" long spider held in the chuck to support the part of the barrel that is greater than 1" in diameter?

 

[ajwcotton]

you can make or use an action trueing jig if you have one Here is a pic I found on google images. Just search action trueing jig and you can get some Ideas of how to make something to work.

 

[ohnomrbillk]

Yes. If someone is chambering a rifle barrel between centers using a steady rest I would assume it is because he lacks a large bore headstock.

I learned old school, and have chambered barrels through the headstock.

I was discussing it with a prominent gunsmith at his shop, and he told me it was better to do this between centers. He cited that the four jaw chuck being cranked down to center everything actually bends the barrel.

I have a friend who does great gunsmithing. He has chambered barrels for me between centers, and they shot like a house of fire.

YMMV