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View Full Version : rifle barrels,,,IN spindle bore,,or OUT on ways???



Alaninga
11-08-2004, 08:34 AM
I have always wanted to have a lathe that will allow me to do barrel work with the barrel mounted inside the headstock spindle, aided by a 'spider' or mini light chuck on the back/left side of the spindle for centering the off side. Been doing barrel threading and chambering out on the ways with steady rest and lots of 'centering'work to be sure of bore's true with centerline, because I HAD TO [small 7/8" spindle bore]. What are your thoughts on the two ways of work mounting?
I now have a Clausing 5913 with spindle hole large enough for barrel holding, but not ready for work yet. Lots of cleaning, lubing and adjusting to do.

rws
11-08-2004, 08:49 AM
My personal choice is through the headstock. Maybe it's just my stupidity, but I can't get a barrel indicated close enough using a steady. When using the headstock method, I can get everything easily indicated, both ends with the spider. Once I setup a barrel, it never comes out until all the chamber end work is done, threading, breech cone (or recess, depending), chamber, all done in one setup. I check my indications after each step just to make sure everythings is good. You won't miss the steady rest!

Alaninga
11-08-2004, 09:03 AM
what type of chuck are you using on the right [main] side? Six jaw TruJust or 4 jaw independant???

rws
11-08-2004, 10:11 AM
I use a 4jaw independent. I align these jaws with the screws on the spider, so I can adjust the two planes easily.

A set-true chuck is nice, but if you have to adjust it, you loosen the 4 bolts to the backing plate and indicate as if it were a 4jaw chuck.

I strive for at least indicating to within .0002" on barrels. I don't think a 6jaw will repeat that close without adjusting, but I may be wrong.

meho
11-08-2004, 05:51 PM
I chamber through the headstock as well.

Although I've never gotten an answer to a question I have about that.

How does one know if a barrel is running absolutely level through the head? A barrel can be indicated to "0" runout at the chuck and "0" runout at the spider and still be running at an angle between the two points. Without a common surface to indicate the height at both ends how do I know it is running perfectly level?

My theory is that there is less error at my 4jaw chuck than there is 30in. down the bed of my lathe. I only use rotating pilot reamers on the barrels that must shoot. A high quality floating reamer holder like the one Dave Manson sells are nice.

James

[This message has been edited by meho (edited 11-08-2004).]

Tinker2
11-08-2004, 06:29 PM
<font face="Verdana, Arial" size="2">Originally posted by meho:


"I only use piloted reamers on the barrels that must shoot."</font>

?????????

meho
11-08-2004, 06:55 PM
Sorry, I should have said rotating pilot.

By "shoot" I mean be as accurate as it can be for competition. Competition accuracy and hunting accuracy are two different things.

I would't spend the extra money for rotating pilot reamers for a hunting rifle.

James

[This message has been edited by meho (edited 11-08-2004).]

plastikosmd
11-08-2004, 09:12 PM
not a gunsmith, and have always (or at least the past year) wonder about one thing regarding indicating barrel bore.
Why is it important to indicate the muzzle end of the bore? Wouldnt it be more imortant to be square to and in axial alignment with the breech? It was always my assumption that the bore was never straight to begin with and constraing between the two endpoints did not accomplish much. Appreciate the answers to follow

sincerely
scott

meho
11-08-2004, 10:01 PM
Hi Scott,

I don't claim to be a gunsmith either, just a hack in training.

The reason to indicate off both ends is so that there is an equal amount of "meat" all the way around the bore at least at both ends. This helps to keep heat warpage consistant. If the breech is off center, the primer ignition can become inconsistent. The muzzel needs to be centered so the front sight can be perfectly centered above the bore and not canted so it is in line and level with the rear sight.

Sure, the hole is not always perfectly straight. I've seen many factory guns that were obviously of center. They shot OK. However all bets were off after about 12 shot or so. The group will open up. Krieger does very well at making straight barrels. They are turned to the desired taper, stress relieved then bored and cut rifled and stress relieved again. This is the differance between a $15 factory barrel and a $300 custom.

I'm sure there are more and better reasons than this. I'm all ears and willing to learn.

James

Alaninga
11-08-2004, 10:59 PM
level?...it might not be. A tight fitting bore stud that is 'true' and fitted several inches into the bore would tell, wouldn't it? You could not only dial in on a spot on the mandrel/pilot,,but run the dial along it to see if one end is higher than the other in relation to the bed. Would have to mount dial base on apron,,or be able to somehow slide it along the ways. This is where an actual 'working' floating reamer holder might be used to eliminate or reduce error from non level spindle. I'll just hope the factory got my spindle 'close'!
alan in ga.

meho
11-09-2004, 12:34 AM
Alan,

I like the long fitted pilot idea. That's something I've not thought of. I have access to a tool grinder that might work. This will be a good project/test for my "real" gunsmith friends that use this method.

Presently I don't have fitted pilots. I just indicate off the grooves.

James

Alaninga
11-09-2004, 05:29 AM
I don't have any long fitted pilots either,,that was just a thought of how 'level' could be checked. Steve Acker in his "Building a Target Rifle" series/book showed he indicates off the end of a fit pilot when 'dialing in' bore. I just place the round ball end of my dial lever in bore, and read off lands/grooves also. I have wondered how difficult finding/fitting a brass/bronze rod would be. Sounds like some "shop time" just getting a STRAIGHT rod to fit WELL in a bore. Nice method, but overkill in my opinion. But then I'm not a proffessional,,just a tinkerer.
alan in ga.

rws
11-09-2004, 08:19 AM
Some people indicate both ends of a barrel thru the headstock. I use a long tapered indicating rod that fits the bore by using the same bushings as the reamer does. This rod is placed in the bore, and the barrel is indicated close to the barrel end, and also down the rod a couple inches. What is happening, is the rod is showing how much "bow" there is in the drilled barrel. My method is to align the breech end of the barrel so I know the chamber is aligned with that portion of the barrel. The muzzle end may be out a fair amount, but the chamber end is as perfect as I can get.

I fail to understand what indicating a bore has to do with the "meat" around the muzzle end? When you cut the barrel to length, you get what you get. You cannot indicate the bore and OD of the barrel. They will be different. How much drift the deep-hole drill had when drilling the hole will not change by indicating. If the place where you cut for the crown is at a place where it drifted a bit, there will be a difference, and it can been seen easily. Will it "walk" around when it heats, maybe.

Alaninga
11-09-2004, 10:32 AM
I think aligning the reamer with 'that' section of the bore is a good idea. If bore [and maybe outer barrel surface] is 'bowed' or crooked [all that I have spun are!]and you dial in both breech and muzzle bores, the reamer is trying to run 'off' at the breech to some degree.
What rod do you use at the breech? Do you use two floating reamer pilots for this rod? I do know that we test bores with our set of 0.0002" reamer [live] pilots. Sure shows barrel quality. We have stopped using some brands of barrels because of 'detectable' variances in bores. We have long rods with tips ground to hold these same pilots. They sure take a rough ride in some bores. Also shows how most bores are tighter at the muzzle end [or should be],,and,,sometimes they will 'skip' when pushed thru,,showing tight and loose spots in bore.
But we have learned some incongruities, also [always did want to use big words]. Using a Hawkeye bore scope proved it's not easy to tell which bores will shoot well. One brand looks rough, shouldn't shoot well, but does. Go figure! We now take a barrel that DOES shoot,,,THEN look inside to see what an accurate barrel looks like!
ha &gt; alan in ga.

meho
11-09-2004, 11:06 AM
Good point RWS. I don't cut a barrel down to length much after turning it. By indicating off the bore and turning a cylinder at the muzzel, flipping it around and a 60 deg. angle in the breach end for a center flipping it again and turning the profile between the two, both ends are centered nicely. Cutting the crown takes little length off the barrel.

When there is not the same amount of metal all the way around the muzzel wouldn't the thinner area heat (warp) at a different rate? I believe it does and want my barrels to heat and cool as evenly as possible. I hope this makes some sort of sense.

James

Lynn Standish
11-09-2004, 11:10 AM
Go here:

http://www.benchrest.com/forums/

Do a search for posts by Jackie Schmidt and Mike Bryant. You will find several discussions on the subject by people who have studied it in depth (indicating the bore).

gundog
11-09-2004, 09:16 PM
I have been thinking of building a steady that will rotate by using a large bearing and a 4 jaw chuck. I have not seen anything like that before but it would solve the problem of the headstock spindle bore not being large enough. I have no plans yet just idears.
Mike

plastikosmd
11-09-2004, 10:23 PM
sounds similar to mr stevensons rest, somewhere there are picures archived here..maybe in tips section, he used more of a cathead style with 4 screws instead of chuck, but either works..prob gonna do the same cause trying to find a rivett 1020 steady rest is impossible
scott