Greg Walley
Member
Is this a rhetorical question Butch? I don’t really know why the some of the chambers I inspected that were finished with the floating reamer holder exhibit these defects. Maybe the tooling wasn’t used properly?
Good Floating Reamer Holder
- Thread starter Curious
- Start date
Is this a rhetorical question Butch? I don’t really know why the some of the chambers I inspected that were finished with the floating reamer holder exhibit these defects. Maybe the tooling wasn’t used properly?
Butch Lambert
Active member
No, I'm trying to understand how you could make an oval or run out with a chambering reamer. I've heard people that have spoke of them. It is pretty easy to chamber a rifle with an oversize base.
It is a serious question.
You can wallow out a chamber by poor technique the same as wallowing out a hole with poor technique.
Poor alignment and less than optimum fixturing of both material (the barrel) and tool holding.
Even metal is not infinitely stiff. Applying stress produces a strain.
I have seen a few chambers bad enough that a plug gauge of the correct size shows a non-uniform gap around the gauge when it is started into the chamber and stops on the typical taper present.
Using a borescope to provide a light source from the muzzle end often makes it easier to see the mismatch.
JerrySharrett
Senile Member
As to an oval shaped chamber, if it were cut on a lathe that had bad spindle bearings and if the reamer was held rigidly it might be possible to cut an oval. A ball or roller type spindle could "lope" as its weight shifted from good bearings to bad bearings.
Notice that on precision cylindrical grinders the wheel shaft runs on bushings not ball or roller bearings.
Butch Lambert
Active member
I could see the reamer cutting like a flycutter. but wouldn't it just produce a wallowed out chamber.
Dave Tooley
Active member
Everyone is looking at the various ways to hold a reamer. Important yes and no, but not the only thing to be considered.
For your consideration and to get further into the weeds. Has there been any discussion as to the best way to setup and align the bore for reaming? Across multiple barrel makers, both cut and buttoned what works? Does it take more than one technique/setup to get consistant results, whatever that means to you? Arguably more important than how you hold the reamer. YMMV
For your consideration and to get further into the weeds. Has there been any discussion as to the best way to setup and align the bore for reaming? Across multiple barrel makers, both cut and buttoned what works? Does it take more than one technique/setup to get consistant results, whatever that means to you? Arguably more important than how you hold the reamer. YMMV
C
cloudrepair
Guest
Im listening would you please share your methods?
I'm very interested.
I feel best with dialing in the throat and muzzle
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zfastmalibu
New member
Dave,
Interested to hear your opinions on this. Method #1, indicate at the throat and crown. Method #2, indicate the first 3" of bore you working on. I know for FACT both methods hold world records at 1k. I personally prefer #2. Reasons are, the bullet and chamber enter the barrel in a straighter section of bore. The crown is also perpendicular to the last section or bore. I dont like that the barrel ends up with runout at the muzzle, but I time it at 12 oclock and have been happy with the accuracy. Method #1 will only cause the bullet to veer half as much from line of sight, curve will be between the throat and crown, the chamber is not concentric to any section or bore, crown is not perpendicular to any section of bore. In my opinion both methods are trying to do the best we can with an imperfect situation. Im not totally satisfied with either, but until we can make a perfectly straight bore, we have to make the best of it. I have seen some really screwed up barrels shoot world class, so Im not sure that this whole thing isnt a waste of breath. I didnt bring up the between centers method, I have checked runout of bores using this method and quickly went away from it. But, even as crude as I find it, it holds records. But I kind of wonder if it also has not helped fuel the Hummer barrel thing. I wonder if there wouldnt be a lot more hummers out there if the chambers were concentric to the bore?
Alex
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Guys,
I moved this subject to its own thread so as to not lose it in this one.
http://benchrest.com/showthread.php?96835-Setting-up-the-bore
I moved away from using pushers to hold my reamers and started using a PTG floating holder. I think Dave calls hos holder a Mighty Might. I couldnt be any happier with the results. i have very little to no runout with my chambers. I also now have better chamber finish than i had with the pusher. I give all my chambers a little cross hatch with scotch bright and i like giving the throat a little spin as well. The ptg holder has made my life much better. I indicate my barrels just like Gene Buckyes indicates his hall of fame winning barrels. i let the muzzle hang at 6 or 12. makes no real difference. Lee
Why not use the flat side of the tool holder as a pusher? You could use an end mill to square it but prob not necessary. Run it up to the flat face of the chuck or cathead, square it up and tighten. Then push with the carriage and whatever ball or reamer holder desired. Even the back of the reamer.
Butch Lambert
Active member
Does it matter?
I've been thinking about the whole reamer pushing thing a bit. Assuming the chamber remains concentric with the bore and the throat is lined up, does it matter if the back end of the chamber ends up oversized? Might it be preferred? I've read AlinWa's methods and it makes a bunch of sense to me. If he's designing that into his reamers why not just use a dead center like Jackie does and welcome any extra fatness that might happen? I understand wanting the machine work to match the reamer and be consistent but it seems to me the consistency will come from running it through the sizing die anyway. I've used the prebore method as well as just running the reamer in using a JGS floating holder with good results, but some of the chambers are tight enough at the back end that my sizing dies don't size them enough to eliminate the click. My lathe is a colchester 15x56 and I've dialed the tailstock in as close as I can get it but it varies with how much shaft is out and pressure on the lock obviously. Any thoughts from Jackie, Al, or others?
I've been thinking about the whole reamer pushing thing a bit. Assuming the chamber remains concentric with the bore and the throat is lined up, does it matter if the back end of the chamber ends up oversized? Might it be preferred? I've read AlinWa's methods and it makes a bunch of sense to me. If he's designing that into his reamers why not just use a dead center like Jackie does and welcome any extra fatness that might happen? I understand wanting the machine work to match the reamer and be consistent but it seems to me the consistency will come from running it through the sizing die anyway. I've used the prebore method as well as just running the reamer in using a JGS floating holder with good results, but some of the chambers are tight enough at the back end that my sizing dies don't size them enough to eliminate the click. My lathe is a colchester 15x56 and I've dialed the tailstock in as close as I can get it but it varies with how much shaft is out and pressure on the lock obviously. Any thoughts from Jackie, Al, or others?
To Shooter71
No
A HUGE no........
('YUGE"....???)
I'm speaking up because you state that "my methods make sense" but they do NOT make sense unless the entire concept of maintaining straight cases is understood. There is only one way to make and maintain straight cases. NO die can make straight cases. And no die ever made can "straighten" a case......nor "fix" a case nor "bring it back to spec" nor any such nonsense. All a sizing die can possibly do is mangle a case and MAKE IT LESS STRAIGHT..........and no press is "stiff enough" nor "straight enough" to help this in any way.
Everything you've ever heard about sizing dies straightening cases is flawed.
There is precisely ONE over-riding and all-important factor to consider when viewing a sizing die.
And that 1 THING is the scrupulous fitment of YOUR die to YOUR chamber.
only that
And this fit CANNOT occur when chambers vary one to another. Unless you have a die fitted to each chamber individually.
And this single item, making identical chambers over and over is the single reason for pushers.......
And any talk about irregular or egg-shaped or fluted or eccentric or lobular/globular/nodular chambers is completely irrelevant to this. Butchered chambers is an entirely different kettle of worms from FITMENT......and not really even worthy of discussion amongst machinists. No pusher/holder/floater/method should produce mushroom-shaped or duck-shaped chambers...... "Runout" and all it brings to the table shouldn't even BE on the table in polite conversation.
opinionby
al
Thanks for the reply Al. Always good info. I may have used the wrong words, by consistency I only meant the amount the base of the case is reduced in size by the die, not anything to do with producing straight or consistent brass. I was more thinking about the dead center producing a larger, but straight and concentric chamber, not being a totally bad thing. But I also can see that using a pusher on a reamer with a fatter base matched to a properly sized die is a more repeatable method.
Why THANK YOU Shooter71 for taking my post in exactly the spirit in which it was intended.
I hesitated to post at all......I perty much only post on old threads in which I'm already a part these days........ but I did.
Oddly enough I posted because of Boyd Allen......
Boyd is a much nicer fellow than me in that he feels he can "say things in a less confrontational way" than is my wont.....and I was just having a liddle rollick over Boyd on another forum (on which I DO NOT post
) Seems Boyd nicely asked a fellow "with all due respect, why don't you do a little experiment....?" upon which one of the perennial haters jumped with both footies, howling "cuz then he couldn't have this conversation with know-alls like you....etc, etc"
Sad, really....
Ohhh welll......."haters gonna' hate" and all that. I'm learning to just crawl back under my rock cuz mos' folks have no use for facts as they tend to kill the typical conversation. And someone always "feels bad" when facts and tests and long-term evidence chains take the mystery out of stuff....
Maybe now that the political climate is changing someone will start a shooting board where people are still allowed to be passionate about truth
Ohhh, and BTW, I haven't found the toolpost to be adequate for driving a reamer even if it's been swept, flycut or machined square for a number of reasons all having to do with flexure and movement due to necessary clearances. In short the driving forces tend to tip, lift and upset the carriage precluding alignment under pressure.....whereas when pushing with a locked-down tailstock assembly with it's wide footprinnt clamped to and using a fairly short section of the ways it's relatively easy to maintain alignment under the pressures involved. Just look at the two assemblies while pushing with your finger and imagining in your mind the load transfer path and you will easily see the difference. Driving with the tailstock is like spreading your stance and blocking your feet to PUSH a large object with a pole....whereas pushing with the toolholder is like doing the same thing...... in a boat.
anotherspateofopinionby
al
I hesitated to post at all......I perty much only post on old threads in which I'm already a part these days........ but I did.
Oddly enough I posted because of Boyd Allen......
Boyd is a much nicer fellow than me in that he feels he can "say things in a less confrontational way" than is my wont.....and I was just having a liddle rollick over Boyd on another forum (on which I DO NOT post
) Seems Boyd nicely asked a fellow "with all due respect, why don't you do a little experiment....?" upon which one of the perennial haters jumped with both footies, howling "cuz then he couldn't have this conversation with know-alls like you....etc, etc"Sad, really....
Ohhh welll......."haters gonna' hate" and all that. I'm learning to just crawl back under my rock cuz mos' folks have no use for facts as they tend to kill the typical conversation. And someone always "feels bad" when facts and tests and long-term evidence chains take the mystery out of stuff....
Maybe now that the political climate is changing someone will start a shooting board where people are still allowed to be passionate about truth
Ohhh, and BTW, I haven't found the toolpost to be adequate for driving a reamer even if it's been swept, flycut or machined square for a number of reasons all having to do with flexure and movement due to necessary clearances. In short the driving forces tend to tip, lift and upset the carriage precluding alignment under pressure.....whereas when pushing with a locked-down tailstock assembly with it's wide footprinnt clamped to and using a fairly short section of the ways it's relatively easy to maintain alignment under the pressures involved. Just look at the two assemblies while pushing with your finger and imagining in your mind the load transfer path and you will easily see the difference. Driving with the tailstock is like spreading your stance and blocking your feet to PUSH a large object with a pole....whereas pushing with the toolholder is like doing the same thing...... in a boat.
anotherspateofopinionby
al
Makes sense.. although the size of my lathe makes me think the flex could be pretty minimal.
I read a lot and rarely post anything. What do you think about the method of using a center for half the chamber and a flat pusher to finish? I haven't tried it. But I might try pushing with the flat front of the tail stock ram and a wide pusher similar to a design you posted. The whole bulldozer blade analogy. But the way the tailstock droops, changes with the amount of shaft out, lock pressure etc. makes me wonder how it affects the reamer. I prebore the chambers and it seems to me you want the first half or so dead nuts and supported by a center or some method until the reamer has more hole to follow. How do you keep the back of the reamer centered at the start, when it's supported on a wider flat surface? Or does it straighten itself right out as soon as it gets some depth? I haven't done enough barrels to test each method to satisfaction.
I read a lot and rarely post anything. What do you think about the method of using a center for half the chamber and a flat pusher to finish? I haven't tried it. But I might try pushing with the flat front of the tail stock ram and a wide pusher similar to a design you posted. The whole bulldozer blade analogy. But the way the tailstock droops, changes with the amount of shaft out, lock pressure etc. makes me wonder how it affects the reamer. I prebore the chambers and it seems to me you want the first half or so dead nuts and supported by a center or some method until the reamer has more hole to follow. How do you keep the back of the reamer centered at the start, when it's supported on a wider flat surface? Or does it straighten itself right out as soon as it gets some depth? I haven't done enough barrels to test each method to satisfaction.
Al,
Interesting observation on pushing with the carriage assembly. I have read that these necessary clearances come into play when turning or threading with the tool upside down...the cutting pressure is applied upwards, which in turn lifts the carriage up until the clearances bottom-out. The manual lathe carriage assembly is designed to take the cutting forces downward. Never thought about this as it relates to chambering...
As I picture this, specifically chambering using the carriage assembly, I see the movement on the vertical plane, as well as potential movement on a horizontal plane due to the v-ways disengaging. Further, if you are getting vertical movement on the carriage when chambering, the positive effects of the pusher, in which the pressure applied to the back of the reamer holder is working to correct any mis-alignment, are reversed. Am I seeing this as you are?
And have you ever measured the movement in the carriage you detailed above? If so, what were you seeing, numbers wise? And have you ever checked deflection on your tailstock ram?
Lots of variables here...lathe quality, carriage weight, clearances, etc. A guy could drive himself nuts thinking about all this. I think I'll go mow the lawns...
Justin