lathe setup to set back shoulder

[Steve314]

I'm installing a pre-fit, long-chambered barrel on a remington action as a first project. According to my measurements, headspacing will require taking about .050 off the shoulder of the barrel.

Any recommendations on setup? here are some observations

a. my headstock is too long to put the barrel through the spindle

b. I intended to do the work in the steady rest with a slip-fit sleeve. This provides
easy access to the chamber for testing headspace (I made a copy of Mike Bryant's headspace tool with the travel indicator). I'm not convinced the slip fit sleeve will preserve the barrel finish as I hoped it would.

c. It might be easier to put a crown saver on the live center and stick that in the chamber.
I've got full DRO in the tenths and can probably cut the shoulder accurately without making measurements on the headspace gage.

 

[MColeman]

What I would do is chuck the muzzle end in the lathe with about 6 inches of the chamber end sticking out and run a live center into the chamber just snugly enough to stabilize it and then make my cuts on the shoulder.

Don't think you can cut the shoulder accurately enough without making measurements on the headspace gauge. It would be pure luck if you got it right. Don't take chances.....measure and then re-measure when working with firearms.

 

[Jkob]

Sounds as if this guy has enough equipment at his disposal to do it differently. Make a spider for the shank! Do it with a piece of tubing and use eight set screws. Mount it on the barrel with the live center in the chamber and set it up in the steady. Once you have it running fairly close, it is a simple matter to inidcate in the chamber by tweaking the set screws.

 

[Cheechako]

By coincidence, I did the exact same job for a friend on Monday. I did it exactly as Mickey suggested. Barrel in an accurate 3-jaw and live center in the chamber. Or you can use a 4-jaw if you don't think your 3-jaw is accurate enough. It's easy to take a cut, check headspace, take another cut, etc until the bolt just barely drops on the GO gauge.

It's a long chambered barrel in a Rem action. No need to get anal about it.

JMHO

Ray

 

[Cheechako]

P.S.

.050" is darn near one full thread. Make sure the tenon and bolt nose counterbore will be the correct dimensions when you finish setting the shoulder back. Measure first, or cry later.

Ray

 

[crb]

I always make a drawing of the rec with the bolt in the closed position and a drawing of the bbl tenon. Measure everything and put the dimensions on the drawing. With the drawing of the rec/bolt you can figure out what the tenon should look like then you can verify that your current tenon is in spec in regards to the counterbore depth and go gauge protrusion.

The only machining tip I have is to lock down the carriage and the compound before taking the cuts.

 

[Steve314]

Thanks for the suggestions.

I made the drawing, and everything looks good according to the clearance specs in Hinnants book. The primary reason .050 is coming off is the lug thickness is .2285.

My chuck is a 6-jaw on a scroll, with 4 adjust screws. Don't want to spring that by grabbing the barrel on a steep taper, but I suppose I could turn a sleeve to match and still indicate the barrel in. Might also make the spider.

Thanks again.

 

[Dave Short]

My chuck is a 6-jaw on a scroll, with 4 adjust screws. Don't want to spring that by grabbing the barrel on a steep taper,

You're only going to face a little off of the shoulder, so you don't have to put the death grip on the barrel..........I don't think you have to worry about springing your chuck. Remember, the screws aren't for centering one work piece after another......They're only intended to be used to center the chuck when it's first installed.

-Dave-

 

[MColeman]

Sounds as if this guy has enough equipment at his disposal to do it differently. Make a spider for the shank! Do it with a piece of tubing and use eight set screws. Mount it on the barrel with the live center in the chamber and set it up in the steady. Once you have it running fairly close, it is a simple matter to inidcate in the chamber by tweaking the set screws.

Jim,
I have all the equipment but I'd still do it the way I suggested. I've done it many times and it works and is not complicated.

 

[Big Al]

Slip fit sleeve has to have a bored internal taper to match the barrel taper.

Stand the barrel muzzle end up, put the sleeve on and bump the barrel on a hard wood surface on the chamber end. Now try and slide it back towards the muzzle. It ain't going to slip! Yes, absolutely do it in the steady rest.

 

[Dennis Sorensen]

Don't want to spring that by grabbing the barrel on a steep taper,

I wrap a piece of 1/8 inch brass rod around a mandrel - like wrapping a spring... to make a circle that I can push onto the barrel. I grab this piece deep in the chuck. You can crush it hard and never worry about springing the jaws.