Hi all, I'm almost finished fitting my 470NE barrel. While I have it in the lathe, can I cut the chamber in the lathe under power? I've done two chamber jobs before, but did it with a Tee handle and hand power. Could I cut most of the chamber in the lathe, then finish by hand?
TIA

Lar45,

Provided everything is running true in the lathe, you'll have better success using the lathe from start to finish. You don't have near the control reaming by hand that you would with power and a good steady indicator.

Good luck,

Malm

Use a floating holder for the chambering reamer and the lath can't be beat, that is how I chamber everything. If you have any questions call me building rifles is how I make my living.
#207-938-3595 Ask for Jud

Jud, just wondering how you clean the chips out?
Do you have a steady supply of coolant and flush them from the muzzle end out the chamber.
I have been buying short and long chambered barrel's and finish reaming them buy hand or on the lathe. I have thought about buying the reamer holder but this has worked for me so far

The absolutely best way to cut a 470 NE chamber is in the Lathe. Use either a spider through the headstock or a center rest and a REALLY ACCURATE floating reamer holder and the job will come out fine! Finish the job with a dial indicator on your tailstock to advance the reamer to the final dimensions.-Rob

[ 07-22-2003, 07:34: Message edited by: Robgunbuilder ]

I am just an amateur gunsmith.
The way I was taught to do it by a real gunsmiths:

I use a test indicator to dial in both ends of the barrel. I use the grooves as the reference, not the riflings.

I use a spider on the left side of the headstock and the chuck on the right.
Alternatively, the chuck can be used on the muzzle and the steady rest on the breech.

The reamer is pushed on by a fixture put in the tailstock that pushes with a flat spot in a cup shaped face that has ~.020" of clearance to the lips of the cup.

I run the tailstock in just slow enough so there is not much torque and no chattering. The pipe slipped over an arm of the T handle on the tap wrench that is holding the reamer, is stopped by the ways, but occasionally I lift up on it with my finger to feel the torque. The compliant finger can introduce chattering, but the ways cannot feel torque.

The reamer is coated with high Sulfer cutting oil. The reamer is pulled back out of the chamber after ~.050" of cutting. It is then covered with chips. The reamer is full of chips if it is full anywhere, and the shoulder is where the most cutting is done. The reamer is cleaned in bucket of gas and oil with a brush.

The bore is cleaned before the reamer is put back in. This can be done best with compressed air, but sends chips across the shop. Alternatively the muzzle can be vacuum cleaned or a cleaning rod can be used on the breech.

The reamer is re coated with cutting oil each time before it is put back in. To cut a 2" chamber, this could take a couple hours.

A 2" dial indicator with magnetic base is put on the tailstock with a homemade fixture on the ram of the tailstock. A stop is put on the ways so the tailstock always returns to the same spot.

The reference case or chamber gauge is put in the end of the barrel and the protrusion measured. The difference of that number and the calculated protrusion when correct headspace is the amount left to cut. That number is then dialed in on the 2" dial indicator.

I figured this out on my own:
When the headspace gets close, I take the barrel out of the lathe and screw in the barrel to the receiver with a barrel vice and an action wrench with grease on the threads and shoulders. I make cases with some of the head removed to figure out how close to getting the bolt closed I am.

[ 07-22-2003, 07:44: Message edited by: Clark ]

I had the "shit happens" experience with FAL barrel I was taking material off the shoulder to headspace. I had it just right for 125 foot pounds of torque, and then I tried it with grease on the threads and lost a few thousandths of headspace. Luckily the Gunplumber Notes said to hit the shoulder with the hammer and some length will grow back. Ever since then I have been afraid to get close without the grease and torque [300 foot pounds for my Mausers] for a reality check.

300 ft pounds for a Mauser?

My mentor and friend uses a 2 1/2 lb sledge and a good wack, and a home made action wrench with a 6" handle. Has been that way for 30 years.

I reamed one barell already. I don't have a floating reamer holder yet, but will get one. I put the muzzle in the chuck and the breach in a center rest and thought I had it dialed in correctly, but on the last bit of the chamber, I had chips mostly in one flute. I hope I didn't ream it too large. I'll do a chamber cast and measure and fireform a case to look at. Is there a site with max chamber dimensions? I'll ream the second barrel with the floating holder. I hope I don't have to order another barrel to finish it. If so, I'll just learn from it and go on. Pac-Nor was pretty fast on delivering my barrels, about 3 weeks.

I think I made the floating holder by buying a #2MT dead center for $3 and putting it in a adapter in the live center and using the lathe to cut the cup shape [after hand grinding off the point].

When you guys are doing work on a barrel in a chuck, how do you secure it such that the jaws of the chuck don't leave any marks in the steel? Wondering, because my multi-hundred dollar stainless, fluted, custom-contour Krieger is going to need threading and chambering if Santa Brown ever brings it. I worry about a big, ugly mark on it.

Clark,

Would it be possible for you to post a picture sometime of your floating reamer holder? It sounds interesting!

Rootbeer,

There are a host of ways to set up a barrel to protect the finish while performing the thread and chamber work. Threading can easily be done between centers and we can employ a steady rest to support the breech end while chambering, while driving the barrel with a collet system, or, in the jaws, using a variety of items from cardboard to brass sheeting between the jaws to protect the barrel.

Sometimes we have to do things to brand new weapons without leaving the slightest hint that we were ever there...

Malm

[ 07-26-2003, 07:24: Message edited by: G.Malmborg ]

I use pennys for protection

I use sheet brass for protection, but the Lothar Walther barrel was so pollished, it would slip in the chuck when cutting threads. I had to rough up the finnish and re align for the started threads.