Chamber reaming between centres

Here's a silly question......but the answer will help me greatly. When chambering between centres using a steady rest, won't the barrel have a brass ring on it from the rest? I have rechambered one of my barrels before (blued) and the steady rest removed the blue. My lathe won't allow me to chamber thru the spindle so I have to work with what I've got. Any advice would be appreciated....barrel set-up, need to dial-in etc.

Its far more accurate to chamber between centers and that is the way it is usually taught in schools. The steady rest is normally run on the thread extension. The threads are cut on centers so it will run true. Also the brass posts on the steady rest will not harm the steel threads. If you use a steady rest with bearings instead of brass cushions make certain that you put a piece of paper between each bearing and the threads when you set it up to give three thousandths clearance so the metal bearings do not harm the barrel threads. I put a .006 thickness of paper between the steady rest posts and the barrel when I set up a steady rest with brass posts as well. In this way the reamer becomes the rear center. The barrel does not even touch the steady rest posts while the reamer is cutting. (the paper is removed before cutting) The steady rest is really just there to support the barrel when the reamer is removed. Step on the Murphy switch and stop the machine before pulling out the reamer. Insert the reamer just .010 short of cutting before re-starting the machine. Failure to do this can leave a light drag mark on the chamber when you pull out the reamer. This drag mark, if you make it is nothing and can be burnished away with steel wool or 320 wet and dry and kerosene. Some reamers will sing or cry when not supported by the steady rest. Don't confuse this with chatter its simply a slight high pitched vibration that builds up in the barrel during cutting and I have never found it to be harmful. I generally squirt a bit of oil on the barrel and grasp it fairly tightly with my left hand while cutting and that chokes the singing abruptly. I find it annoying like a yowley cat going at it in the back yard when your trying to sleep.

Contoured barrel blanks have a cylindrical segment at the breech end that is sufficiently long to cut the tenon and leave a cylindrical place for the steady rest. Plus, this cylindrical segment leaves options for setting the barrel back.

An oiled length of abrasive fabric, fabric side against the barrel, serves as a bearing. The steady rest fingers should contact with a light touch. The bearings will need to be relubricated occasionally, and they will squeal after it is time.

Turn the OD of the blank concentric to the bore second. Turn the muzzle end to a concentric OD first, then drive the barrel with a collet when the barrel is swapped end for end to work on the chamber and tenon.

Someone else can argue the case for chambering in the steady rest, or not. I think it's a silly discussion, as it's clear the best rifles can be built using the steady rest or worked through the head stock.

AeroE said:

Contoured barrel blanks have a cylindrical segment at the breech end that is sufficiently long to cut the tenon and leave a cylindrical place for the steady rest. Plus, this cylindrical segment leaves options for setting the barrel back.

An oiled length of abrasive fabric, fabric side against the barrel, serves as a bearing. The steady rest fingers should contact with a light touch. The bearings will need to be relubricated occasionally, and they will squeal after it is time.

Turn the OD of the blank concentric to the bore second. Turn the muzzle end to a concentric OD first, then drive the barrel with a collet when the barrel is swapped end for end to work on the chamber and tenon.

Someone else can argue the case for chambering in the steady rest, or not. I think it's a silly discussion, as it's clear the best rifles can be built using the steady rest or worked through the head stock.

Click to expand...

Well AreoE I really don't have a clue what you are trying to say or how it pertains to the thread. This is what he asked.

(between centres using a steady rest, won't the barrel have a brass ring on it from the rest? I have rechambered one of my barrels)

Are you trying to start an argument about setup or are you trying to start a new thread?

Without writing a long drawn out novel, I thought that was sufficiently clear. Except I did not address the problem of rechambering a barrel with an existing tenon. However, if there is real estate to run in the steady rest without a bearing, there's room to add one, too.

You advocate running the steady rest on the tenon threads. I posted a different method, that not only keeps the steady rest off the threads, it keeps the rest out of the way for the threading operation, too, and addresses the question about brass markoff from the brass fingertips from a steady rest that does not use rollers.

A method taught at a gunsmithing school, in case you are curious.

Do you run the hardened steel rollers on a steady rest equipped with such on the tenon threads?

AeroE said:

Without writing a long drawn out novel, I thought that was sufficiently clear. Except I did not address the problem of rechambering a barrel with an existing tenon. However, if there is real estate to run in the steady rest without a bearing, there's room to add one, too.

You advocate running the steady rest on the tenon threads. I posted a different method, that not only keeps the steady rest off the threads, it keeps the rest out of the way for the threading operation, too, and addresses the question about brass markoff from the brass fingertips from a steady rest that does not use rollers.

A method taught at a gunsmithing school, in case you are curious.

Do you run the hardened steel rollers on a steady rest equipped with such on the tenon threads?

Click to expand...

If you read up I said this:

I put a .006 thickness of paper between the steady rest posts and the barrel when I set up a steady rest with brass posts as well. In this way the reamer becomes the rear center. The barrel does not even touch the steady rest posts while the reamer is cutting. (the paper is removed before cutting) The steady rest is really just there to support the barrel when the reamer is removed.
I'm installing a barrel today I'll take a couple pictures for you.

In the first picture you can see the steady rest posts are set down on .006 inch manila tab. The posts are locked into place and the paper pulled out. This allows the reamer to become the rear center and the barrel to float. The reamer is piloted and is tapered. The simple laws of mechanics force it to take the simplest path as it cuts, which is straight down the bore. Chamber reamers are not reamers at all. They are form cutters and cut incredibly hard. They will not cut over sized unless acted on by an outside force.
If your steady rest has brass cushions you can set the bushings directly on the threads if you wish. It will not harm the threads. If it has steel bearings, or even rotating bearings you should set the posts so that they are barely touching the threads so they will not be damaged.
In the second picture the paper has been pulled out, reamer installed and ready to begin cutting. The apron of the machine is locked and used as a stop so that the tail stock can be returned to the exact same spot between cuts. When the machine is switched on a full flood of coolant will start up both through the bore and from the back to clear the chips. The coolant is switched off for the photo. Setting it up this way won’t hurt the blueing at all as should be evident by the pictures.

I have to apologize for failing to carefully read your first post above; I scanned the wall of text, and missed the real content and what you had to say.

Sometime in the last two or three weeks I had read a similar claim about running the steady rest on the the tenon threads (that post may not have been on this site), and assumed you were the same poster. The other person did indeed run his steady rest fingers directly on the threads.

I should have mentioned that with some calibers you do have to run the steady rest posts directly on the threads. Reamers with very sharp shoulders or slight body tapers will chatter like a bastard without stabilization. Even wrapping the barrel with lead wire and using hi pressure cutting fluids like ridged and Cutmaster sulfur based oil will not break it some times. Standard 06, 08 and belted magnum style cartridges seldom give this problem even when using standard coolant. The new short magnums, ultra magnums and the 284 wildcats can turn into a war some times. I would use ridged or Cutmaster all the time as it cuts nicer but it takes to much time to switch it over. One day I will buy another lathe and dedicate it to collets, chambering and cutting oil and use the other for threading and turning.

Speerchucker, thanks for the details in your posts of how you chamber between centres. I'm new to smithing and trying to gain as much advise as possible. When you chamber between centres how do you find it best to hold the muzzle end and supply the cutting oil down the barrel? Thanks.

Speerchucker,

You're the kind of guy I wish I could work for, for about ten years...

You know your stuff.

Well there are lots of ways of doing it. With either way I use you have to first recut your centers with center cutting reamers. The first picture shows a Morse taper with a hole drilled through the center to allow coolant to flow through it. The other part with the 2 O rings is inserted into the off side of the spindle. It’s held in by a screw in collar which is not shown but its straight forward. Oil is delivered through an air chuck or commercial water swivel so the hose does not twist up. The barrel is put between the centers and is then clamped in by a three jaw chuck to dog it off and turn the barrel, which of course must be rapped and dialed in (some people don’t bother). Or a 4 jaw chuck which is dialed in. It can also be held back against the center using a drive plate, spring and a lathe dog. Like I said, lots of ways. There is no need for a rubber seal it won’t leak as long as you have a clean 60 center with a hole drilled through it and have recut your barrel centers cleanly to 60 degrees.
The second system is simpler but you have to make a bunch of stuff. The system still uses an air chuck as a swivel or you can buy a commercial swivel. In picture 4 you can see the assembled unit. Picture 2 shows the air chuck swivel at the back of the machine. Picture 5 shows the 5C collet, 5C collet delivery adapter with drilled center and a barrel turned to match a common collet size. After you recut the centers you have to put the barrel between centers and turn an area on the muzzle so that it can be held by the collet. I happen to use 5C collets because they have an internal and external thread. The delivery system with the 60 degree center with the hole through it can be made to screw into one of your 5C collet stops or you can just make it from scratch as I did. Put the barrel between the centers on the machine. Load up the pressure with the tail stock to seal the center. Tighten down the collet. Plug in the oil line and turn on the pump and oil runs through the barrel. Not much to it, once you see it done.
I have done it many other ways too. I'll try anyone's system unless of course it seams idiotic right from the word go. The key for me is it has to work and it has to be fast. When you do it for a living there isn't time to piss around to much. This system happens to be to be very fast as there is nothing to dial in and you can take deep cuts as the fluid clears the chips. It is as accurate or more accurate than the rest of the systems. Every time some thing must be dialed in you create errors. No measuring device is infinite or perfect and I have yet to see a human that never makes mistakes or has perfect eyesight.

I made a spider to install on the barrel and run the spider in the steady rest.

Yeah I made a couple too and I also bought the tap for the Remington 700, Winchester 70 and the 98 Mauser barrel threads and I used to make consumable screw on bushings that I could screw on to the thread extension and then take a small skim off of between centers and drive them in the steady rest. The spider added 20 minutes to the job and was abandoned. The bushings however worked well but I eventually abandoned those as well. They just added an extra step and were really unnecessary. The bronze bushings in my steady rest seem to last about 5 or 6 years between replacing so I eventually just gave up and went back to running on the threads.
In one shop I worked in we had a small tool room lathe with a 24 inch bed. We had a 4 jaw on the front and back and we had to dial in both ends of the barrel each time we did a job. That rig was a real time waster and the guy that owned it eventually bought an old Southbend lathe with a 40 or so inch bed and mickey moused a Hardidge collet chuck on it and dedicated it to barreling. It was a fairly light, old, flat belt drive machine but really how much machine do you need to drive chamber reamers.

Hi speerchucker,
I too chamber using the steady rest method, also driving the muzzle end with a crawford collet chuck set up.
However i use a floating reamer holder so hence have the steady fingers directly touching the tenon thread.
I notice in one of photos that you are holding your reamer in ER style milling collet device.
I can only assume that your centreline height between the headstock of your lathe and the tailstock are equal-equal so as not to put any undue strain on your reamer.
On my old Colchester at 24" the tailstock centreline is .002" lower then the headstock so that tecnically rules out using the collet holder which i believe would be a superior method for holding the reamer then the floating holder, or am i missing something in your set up. Thanks

Ian.

Well lathes are kinda designed so that the two centers meet exactly. It would be impossible to do any sort of machining if they didn't I guess. But it is understandable that the ways do become worn after a while and lighter machines can suffer party crashers and the bed can be sprung during moves or whatever. With new machines it should not be an issue but it is simple enough to check and I do periodically check it every other year or so. Buy one of those $40 dollar male/female center finders and clamp it into the collet on your tail stock female side out. I have tried doing this in Jacobs chucks in the tail stock but you will seldom find a Jacobs chuck that is true so use a collet and make sure the collet runs true by running it in the headstock or mill first. Then put a center in your spindle making sure that everything is first clean or cut a 60 degree center on a piece of material in your 3 or 4 jaw chuck. Run the female end of the center finder in the tail stock up to the male center in the spindle and do a visual inspection. If the center finder is split apart at all determine whether it is out up and down or side to side. If its out side to side adjust the tail stock to compensate and realign it. If it is out up and down use a micrometer to measure the split and determine the amount needed to compensate and shim the tail stock. I personally have never had to correct a machine of my own but I did help a buddy correct an old Russian machine one time. If memory serves it took us 6 beers to get it straightened up and its been fine for ten years. You could do the same thing by putting a squared off piece of precision ground 1/2 inch material in the tail stock collet. Then turning a piece of material in your three jaw or four jaw to 1/2 inch and running the two together. It would accomplish the same end. But if you have a mill you probably have a center finder. Six of one half dozen of the other. This will correct any axial run out. You can check lineal run out by putting a piece of precision ground stock in the tail stock collet and then put a dial indicator on the apron and run it up and down the length of the material and shim this out as well. I have never seen one run out lineally. All in all I do know guys that run reamers in Jacobs chucks all the time and never make outsized chambers and those fool things are generally out by a mile. I think I tend to get a little carried away with some setups. I do everything on centers and in collets or in one shot in three or four jaws. But it may be a bit of an overkill. But it does seem to keep me happy and I sleep at night. Like the old saying "what ever floats your boat or makes your bum hum"

speerchucker,
Please could you give me a link to the type of centre finder you describe, i am in the UK and such a device may have a different title to what you have in the USA, Oops sorry Canada Many thanks

Ian.

There is a picture of one. Starret makes them, everybody makes them. They can be had with male and female 60 tapers plus a whole raft of other tapers or oddly shaped ends. With this one you could hold the main body in your tail stock collet and the small end on the right in a collet in the headstock. There is a spring that runs through the main body that pulls the 2 ends together. Or you could buy one with female ends and do as I described above. If there is any misalignment you can see it with the naked eye or feel it with your fingers. You can use a caliper or micrometer to measure it where it splits to figure out how much its off. Trust me .001 inch stands out like a sore thumb on these things. If its only out a tho or so I probably wouldn't worry about it. Most machines are surprisingly close even the so called cheep Asian machines. They do work great however if you happen to cut the odd taper by off setting your tail stock. Makes it a breeze to set it over a certain number of thousandths by just measuring it at the split and even simpler to set it back. Tools4cheap LLC Online Machine Shop Tooling Store: Edge / Center Combo Finder 1/2",Fisher Machine Products

That's not what I was taught that the center finder is for. To check tailstock alignment just put a center it and an indicator in the headstock. Indicate the center and you've got it. Try both methods and I think will prefer the indicator.

I take it you are clamping a dial indicator on some part of the chuck and then rotating the chuck round a center in the tail stock. Works just peachy, its just a pain in the butt and a lot of time to set up to. The guy that taught me said the proper way was to use an internal indicator clamped into a collet in the headstock and indicate on the inside of the tail stock by rotating the spindle by hand and using a mirror to read the indicator when it was upside down or facing away from me. Then he told me to use a center finder/edge finder, stop wasting time and get my ass back to work. LMAOROF Ockham's razor ALWAYS applies!