Chambering

How do you chamber between centers if your headstock is too deep to allow support of the muzzle end of the barrel?

Uh, can't chamber between centers, a physical impossibility.

Think: STEADY REST

Muzzle chucked up and dialed in (remember your are dialing the barrel OD, not the bore, so this method is usually a few thou off, OK for a hunting rifle but a no-no for the accuracy crowd).

Breech end held in the steady, most folks run on the barrel tenon or threads, some turn a true area on the breech while the barrel is still between centers. Be sure to lube the steady rest jaws.

Reamer held in an appropriate device in the tailstock.

Hunt and peck, brush and wipe, squirt cutting fluid, and repeat and repeat and repeat and repeat.

Did I say repeat and repeat and repeat and repeat?

After you have chambered a couple of barrels this way, you will learn to appreciate a pumped coolant system whereby the coolant is pumped through a rotary union into the muzzle and out past the reamer, flushing chips and keeping that reamer in good condition, not to mention the time saved.

Then you will go out and buy a lathe for chambering that has the proper spindle dimensions for passing the barrel through with the muzzel held in a 4 screw cat head and dialed in to the bore.

PM me if you need photos.

SilveradoHauler said:

After you have chambered a couple of barrels this way, you will learn to appreciate a pumped coolant system whereby the coolant is pumped through a rotary union into the muzzle and out past the reamer, flushing chips and keeping that reamer in good condition, not to mention the time saved.

Then you will go out and buy a lathe for chambering that has the proper spindle dimensions for passing the barrel through with the muzzel held in a 4 screw cat head and dialed in to the bore.

PM me if you need photos.

Click to expand...

Can you post some pictures or drawing on how to build this coolant pump set up and rotary union?

You can see some coolant systems here: http://www.gtrtooling.com/prod02.htm

Another option is to make a long 'chuck' out of DOM tubing with a spider at each end and run that in your chuck and steady. The bore can then be more accurately aligned to the spindle with the independent spiders.

If I understood the question correctly it's not that your spindle bore isn't large enough, but that the lathe head is too long. If the barrel is sleeved with zero play you can still use a spider on the spindle tail.

GsT

The coolant union you use will depend on the lubricant. pressures, and flow you have available / choose to use. After you decide that, contact Dueblin for assistance with picking a coolant union.

I would be interested in what Silvarado uses for coolant in his chambering setup, i.e. a water soluable or a cutting oil.

Rotary Union, and Coolant

Soluble Oil. I use Fiske Cut-N-Cool. I mix 3 parts water to 1 part oil, works great. Standard mix ratio is 20 to one, so I run it much heavier. I use Fiske because I got a barrel for free a long time ago! You can use it straight, but the water helps cooling. My mix is probable 2 to 1 now as I often add straight oil. Be prepared for the coolant sump sludge if you live in a warm area, you can buy treatments for the sump that will prevent this and allow the mix to last longer.

Fiske says it is a heavy duty soluble oil with sulfurized and chlorinated compounds. Ya gotta have sulfur and that bad chlorine stuff to make the reamer cut smoother and last a long time.

Dave Kiff at PTG uses Rust-Lick 711, a similar product to the Fiske I use. Another good one is Texaco TransultecX-H. Also Chevron ULtRA-Cut AXH They all have high sulfur and chlorinated compounds.



Once you use a muzzle flush system, you will kick your self all over the place for not doing it sooner!!!!! It is at least 10 times faster than the brush and wipe hunt and peck method, gives a much better finish, and makes that expensive reamer hold its sharpness much longer. I made mine about 15 years ago. After my first chamber job using it, I went out for lunch with the shop guys and had a small celebration.

You are better off making a rotary union. The commercial unions, like the Dueblin, are useless, as they have ball bearings. If you use a commercial union, you gotta make adapters for the barrel anyway, so why not make the whole thing? Mine is made from a few pieces of steel bar stock, a piece of moly impregnated nylon, and two o-rings. The coolant lubricates the rotary union. Plus some soft teflon for seal plugs at the muzzle, I put a good 60 degree center in the muzzle, the union has the tapered teflon hollow plug, and is designed to force the plug into the muzzle center, sealing the fluid and keeping it where it belongs. You do not want any leaks, as the pump will flood the shop floor very fast! The system works great and never has leaked after at least 150 barrel jobs. The gre-tan system will work, but has some shortcomings.

I run at 300 rpm for the average chamber job like a 308 or 30-06 size reamer. higher for small guys like 223's, and slower for the big ones like 338 Lapua, 416 Rigby, etc. If things are set up correctly, it sometimes can be real easy to run the reamer in too far, the cutting is so good. All the chips are flushed out with the coolant, so you need a deflector at the base of the reamer to keep from making a real mess. You will need a good depth indicating system on the tailstock. And a anti rotation stud on the lathe headstock next to the cathead. My pump is in a 10 gallon sump sitting behind the lathe, a high pressure hose connects it to the rotary union through a Swagloc fitting. The coolants returns through a catch pan and hose & strainer back to the sump.

Mine can be used in two ways: With the barrel extended through the headstock, muzzle held in the cathead, or with the muzzle in the chuck and the breech held in the steady. (I have a extension pipe that extends through the spindle, with the rotary union held in an adapter in the cathead)

I will take a few photos tomorrow and get them posted.

My thinking: A guy that calls himself a gun builder should be able to build his own rotary union and pumping system, and other tooling like barrel vise and action wrenches, the list is endless.

Something worth remembering: PTG reamers work better with muzzle flush than the Manson (Old Clymer) reamers, as Dave Kiff extends the reamer flute out past the removable pilot bushing. And I will show how to notch the bushing retainer screw for improved flow.

Only use removable pilot bushings. Fit a snug pilot to the bore.

When you get into this system, you will neve go back to the old method.

To eliminate having to dial in the barrel in the chuck and to overcome any run out between the bore and OD: Use a piloted countersink to produce a 60 degree center in the each end of the barrel, then strap the barrel with dog to a dead center in the headstock. The dead center can be through drilled to allow coolant to pass through it.

To strap the barrel to the center, use a faceplate partially threaded onto the spindle(assumea a threaded spindle), fasten the barrel and dog to the faceplate with a strong leather lace as tightly as possible, then tighten the faceplate to pull the lace tight.

Then, using a center in the tailstock, turn the rear portion of the barrel to make the exterior concentric to the bore. Then mount the steady rest so it runs on the just turned section and back off the tailstock.

If you have a non-threaded spindle, getting the barrel firmly held to the headstock center will be slightly more difficult.

ulav8r said:

To eliminate having to dial in the barrel in the chuck and to overcome any run out between the bore and OD: Use a piloted countersink to produce a 60 degree center in the each end of the barrel, then strap the barrel with dog to a dead center in the headstock. The dead center can be through drilled to allow coolant to pass through it.

To strap the barrel to the center, use a faceplate partially threaded onto the spindle(assumea a threaded spindle), fasten the barrel and dog to the faceplate with a strong leather lace as tightly as possible, then tighten the faceplate to pull the lace tight.

Then, using a center in the tailstock, turn the rear portion of the barrel to make the exterior concentric to the bore. Then mount the steady rest so it runs on the just turned section and back off the tailstock.

If you have a non-threaded spindle, getting the barrel firmly held to the headstock center will be slightly more difficult.

Click to expand...

Right out of the South Bend Book. Who has leather line shaft belting lace in their shop today? Probably no one but me.

Fowler even shows how to do this in his funny book.

I have done this in my younger days. It is real prone to causing reamer chatter.

This will work, but it is old school. OK for throwing on a A&B or Douglas on that M98 for a deer gun. But, for a newbie lathe hand and barrel worker, I would not recommend this method, as it takes attention to keep that barrel out of your face.

When going for the accuracy jobs (benchrest and 1000 yarders) we indicate to a precision bore plug in both ends of the barrel using tenth reading dial indicators. There is no real substitute for through the spindle and indicated in on both ends. As I use muzzle flush, the barrel is through the spindle, so I indicate all barrels in to "benchrest specs" even if it is a 458 Lott or a 500 Jeffery.

And sometimes I will indicate to the grooves using a tenth reading indictor with a long 3 inch pointer, but it is a real PITA to use, jumping over the lands and such.

Note: Check those pilots on the bore piloted center cutter, I have several. You may be suprised when you measure them and compare them to actual bore size at the muzzle of the barrel you are working with. "Automatic Runout".

Cutting oil

There's use of cutting oil, and then there's use of cutting oil.

600psi at work. . .



As mentioned, the dumor couplers are the only way to go. If using oil pressure below 400psi also consider a pair of System One racing oil filters paired up with a dual oil filter adapter available from Transdapt. Plumb with braided hose and it's as solid as solid gets. This is all race car stuff. The System One filter uses a cleanable/reusable screen that goes to 10 microns. The important thing here is volume, not getting every last little piece of grit.

Above 400psi you'll have to make your own filter enclosures. I found this out the hard way on Christmas day 2005 when one of the filter's grenaded and shot oil all over the shop.

Experience is never cheap.

You want the filters because the Dumor couplers use carbide seals and they won't tolerate heavy particulate forever. Treat em right and they last a very very long time though.

Good luck.

Chad

I made up a collar for the tail end of the spindle, bored for a piece of hollow Thomson ground stock and split with a clamp screw so the shaft can be adjusted for length. Runs true within a thou' or two. More than good enough since none of the barrels have a straight bore anyway ;-)

Shaft (tube) has a hardened center in one end, drilled through for eventual coolant passage, and the tail end threaded for a rotary coupling. One nasty thing I found out, when you bore this case hardened tubing and thread it, it expands on the OD. Same sort of thing that makes the bore of a buttoned barrel expand when you turn the OD down. So the bore of my coupler is a bit larger than the shaft so I can get it in. May grind the shaft some day and sleeve the coupler to improve runout ...as though it really matters.

This for barrels too short to reach all the way through ... ie, AR-15's ... or under 24" or thereabouts on my lathe (Graziano SAG-12S).

Longer than that, I have a short collar with 4 setscrews, a 'cathead' if you please, for the tail end, and either a 4 jaw chuck or a shorter cathead mounted to a D1-4 backplate. Saves a couple inches and easier to dial in than the 4 jaw.

Chamber end gets indicated to 'tenths', up as close to the throat as I can get. Muzzle end, I use a half thou' indicator ... or the spindle center. In reality, the AR's have been done from blanks long enough to reach all the way through, so the center only gets used for crowning on them.

Sil Hauler,
How do you chamber? What do you indicate? What are the bore plugs that you use? You haven't given much info. The fellow that answered how he works between centers is about the topic of this thread and how he does it.
How close are your chambers?
Butch

Let me rephrase my original question -

I have a SB 14 1/2 x 7' lathe, from the end of the shaft to the outside edge of the chuck it measures 28".
How do I chamber a 26" barrel?
I am just starting my learning process.
Pictures would be really helpful.
Single shot handgun barrels will need to be done with the same setup I would assume.

stevea2003 said:

Let me rephrase my original question -

I have a SB 14 1/2 x 7' lathe, from the end of the shaft to the outside edge of the chuck it measures 28".
How do I chamber a 26" barrel?
I am just starting my learning process.

Click to expand...

make one of these:

I have the device that 300sniper suggested but I still have too much spindle to support the outboard side of an eighteen inch barrel. I would greatly appreciate any ideas.
Shawn

i do have an idea that i am positive would work although i have not tried it yet. you could take a long (maybe about 12"-14" or so?) heavy wall tube and drill/thread for a spider at each end, mount one end in your chuck and support the other end with your steady rest. the barrel could be held and adjusted dead true just like it would though the spindle with a 4 jaw and spider.

i have used my action truing jig to precision thread 12" 10/22 barrels for suppressors with success. this idea is essentially the same as described above.

the only problem i can see with this is the fact that i like to locate the high point of the muzzle after i have the chamber end dialed in so i can clock it up when the receiver is torqued onto the barrel. with the muzzle being inaccessible, this would be near impossible to do.

edit: something like this only longer so you have a longer support on the barrel and using a steady rest:

Shawn S. said:

I have the device that 300sniper suggested but I still have too much spindle to support the outboard side of an eighteen inch barrel. I would greatly appreciate any ideas.
Shawn

Click to expand...

i was able to do the muzzle work on my 18.5" barreled 308 by threading the id of a piece of 1.25" x .125" wall dom tube to 1.062"-16. after i did the chamber work on the full length blank, i threaded the tube onto the chamber end and used it as an extension to reach the spider on the back of the spindle. if you are looking to do chamber work on an 18" blank, the method i mentioned in my last post may be worth a try.

you can see the threaded tube extension on the chambered barrel in this picture.



this is the amount of stick-out i needed on the muzzle end for the muzzle brake. this is on an 18.5" barrel.

Thanks for the idea, the pictures are most helpful. I will have to make one up as soon as I get a chance.

Shawn

Here's another way to setup between centers...





Notice the bent lathe dog between the drive plate and plywood keeper...

MarinePMI said:

Here's another way to setup between centers...

Notice the bent lathe dog between the drive plate and plywood keeper...

Click to expand...

Is that a bullet mould that I spy in the first pic?