turning fired brass?
- Thread starter AusFclass
- Start date
I never heard anyone suggest that fireformed brass couldn't/shouldn't be turned.
What I can imagine them implying is that it's better to turn necks before fireforming, so that you can head-off donuts by taking a bit off shoulder area that will make it's way into necks.
Kinda too late to deal with donuts afterwards(without reaming), and reaming is not as precise as turning(tension dependant).
But if you don't have a donut issue with your fired brass, or you don't seat bullet bearing into any donut, then you won't have any issue there. And regardless, you can turn/re-turn necks anytime.
What I can imagine them implying is that it's better to turn necks before fireforming, so that you can head-off donuts by taking a bit off shoulder area that will make it's way into necks.
Kinda too late to deal with donuts afterwards(without reaming), and reaming is not as precise as turning(tension dependant).
But if you don't have a donut issue with your fired brass, or you don't seat bullet bearing into any donut, then you won't have any issue there. And regardless, you can turn/re-turn necks anytime.
AusFclass said:
That's silly.
I neck-turn new brass if I find the neck wall thickness to be irregular.
I routinely neck-turn fired cases - after they've been annealed and sized properly to fit the turning hardware - sometimes two or three times to get them reduced to a thickness I find works best for long case life.
It's common practice to neck-turn cases made from parent brass for another cartridge, then once the brass has been used in the intended chamber (fire-formed) take another pass at the necks to bring them closer to desired thickness.
Proper annealing helps reduce problems from work-hardened brass, not only for neck turning operations but also when it comes time to size those necks or bump shoulders back.
(I anneal the neck and shoulder at the same time to where I can see a change in the case wall surface color similar to what is evident on new Lapua cases: the color change extends maybe 3/4 to 1x the case diameter at the shoulder below the case wall / shoulder junction. For 308 it's maybe 5/16" - 3/8". Go too far & case walls may be compromised & you don't want to do that or get the case heads too hot either....)
IMO, you should beware of turning fired cases that have bee resized with a bushing die, the reason being that the unsized portion next to the shoulder will be made thinner. Recently, I re-turned a bunch of cases, to increase neck clearance slightly. Before I did, I sized them all, paying attention to bump, with a one piece FL die, and then expanded them, and turned. Luckily, my die has a neck ID that does not over work the cases. Good luck with yours.
BoydAllen said:
i considered that as a possible problem but decided taking lapua .243 cases from .273 down to .270 shouldt unduly weaken the necks.
as a side note when removing the neck turner from the turned case do you have any prefered method of reducing the the back cutting effect? on a lathe i just wind out and then back to my cut depth before taking the next pass but cant do that with a neck turner!
bozo699
Gold $$ Contributor
AusFclass,AusFclass said:
I don't back it off I just go slow in the reverse direction and it is like taking a final small cut. I understand what your saying with a lathe tool bit that would not be proper but the way my neck turner bit is made I don't think it will hurt anything, although I am interested in what others have to say about this.
Wayne.
IMO it is best to do a "bad" job on the way to the shoulder, advancing the cutter in a manner more quickly than will produce a clean cut. By doing so, material will be removed while backing up from the shoulder to the mouth, which should be done slowly, to give a good finish, and uniform dimensions. The advantage of this approach, when combined with a loose hold on the turning tool and a cordless drill that is not rigidly held, is that the neck is pinned to the mandrel the whole time that the cutter is on the neck. This makes thickness runout independent of case to mandrel fit ( within reason) and by doing so can significantly reduce heating problems that can result from the wring on fit that many think is required. Radical stuff, but I have done the the turning and measuring to verify. I expect some flack on this from the "a tight fit is a must" crowd. So be it. 
bozo699
Gold $$ Contributor
BoydAllen said:IMO it is best to do a "bad" job on the way to the shoulder, advancing the cutter in a manner more quickly than will produce a clean cut. By doing so, material will be removed while backing up from the shoulder to the mouth, which should be done slowly, to give a good finish, and uniform dimensions. The advantage of this approach, when combined with a loose hold on the turning tool and a cordless drill that is not rigidly held, is that the neck is pinned to the mandrel the whole time that the cutter is on the neck. This makes thickness runout independent of case to mandrel fit ( within reason) and by doing so can significantly reduce heating problems that can result from the wring on fit that many think is required. Radical stuff, but I have done the the turning and measuring to verify. I expect some flack on this from the "a tight fit is a must" crowd. So be it.
Not from me, this is what I was trying to say, just didn't say it as well as you
Wayne.
I've cut some of the wobbliest cases perfect somehow, and this tells me that tight fitting, centerline precision, just doesn't matter -provided I'm not taking too much in a pass. I don't wanna take so much that brass is peeling off or walking up the cutter.
Another qualifier as implied is that atleast one end(the turner or the case) should be truly free floated
(all axis).
Bozo, I know you love your toys, but the 21stCentury lathe setup does not qualify in this regard. Although wobbly enough, it's movement is resisted from centerline -on both sides.
Hyped as concentric, but actually not good with turning, because cases are NOT initially concentric.
So every wobble in a case pinned to centerline, creates angles at the cutter.
With freehand turning the turner wobbles with the case, and there is little anglular deviation w/resp to the mandrel.
A tight mandrel fit also reduces angular deviations, but as mentioned it ain't free.
Another qualifier as implied is that atleast one end(the turner or the case) should be truly free floated
(all axis).
Bozo, I know you love your toys, but the 21stCentury lathe setup does not qualify in this regard. Although wobbly enough, it's movement is resisted from centerline -on both sides.
Hyped as concentric, but actually not good with turning, because cases are NOT initially concentric.
So every wobble in a case pinned to centerline, creates angles at the cutter.
With freehand turning the turner wobbles with the case, and there is little anglular deviation w/resp to the mandrel.
A tight mandrel fit also reduces angular deviations, but as mentioned it ain't free.
BoydAllen said:
Yes that's quite true: if you only size a portion of a case neck, then try to turn that portion and what's behind it, your case neck will be thinned more than you want below where the bushing die stopped.
My practice with fired cases destined for neck turning is to size necks as far down as possible then use an expander mandrel of the same brand as my turning mandrel to bring the neck I.D. into uniform diameter. Turning is best done with a suitable lubricant too, both inside the necks and on the cutter.
If your cases tend to grow donuts this has an additional advantage of pushing the donut metal to the outside where the neck turning cutter can remove it.
bozo699
Gold $$ Contributor
Actually Mike I like nice tools, I like Cadillacs, I like most anything the Mauser brothers or John Browning had to do with, another words I like top of the line beautifully crafted well thought out precision equipment, and I like innovative ideas, Henry Ford, John Deere, etc..etc.. I own a 21st Century turning lathe but have not used it long enough to form an opinion, I can see by looking at it that it was a innovative idea and of quality construction, and made in America by a true American which gives it three points right off the bat to me, had it been stamped out in China I wouldn't have taken a second look at it no matter how well it worked!! I had planned this winter to take my NT-4000 neck turner that does a good job turning necks but it is a pain to adjust, my Neilson, (not used yet ) and my new 21st Century (also not used), and my K&M and do a side by side honest comparison of the 4 turners and do a little review of my findings. I have learned a lot from you Mike and am always interested in your thoughts, I don't always understand what your trying to say to me but I listen and ask, this is no different I am interested in your method and tools of choice. Even cavemen had tools (toys) without them they could not have survived, without improving on them we still would be living in a cave spending our days foraging for foodmikecr said:
Wayne.
BoydAllen said:IMO it is best to do a "bad" job on the way to the shoulder, advancing the cutter in a manner more quickly than will produce a clean cut. By doing so, material will be removed while backing up from the shoulder to the mouth, which should be done slowly, to give a good finish, and uniform dimensions. The advantage of this approach, when combined with a loose hold on the turning tool and a cordless drill that is not rigidly held, is that the neck is pinned to the mandrel the whole time that the cutter is on the neck. This makes thickness runout independent of case to mandrel fit ( within reason) and by doing so can significantly reduce heating problems that can result from the wring on fit that many think is required. Radical stuff, but I have done the the turning and measuring to verify. I expect some flack on this from the "a tight fit is a must" crowd. So be it.
turning on the back cut????? im only new to the neck turning game so i thought i might have been missing something but ill give it a go. thanks for the tip!
bozo699 said:Actually Mike I like nice tools, I like Cadillacs, I like most anything the Mauser brothers or John Browning had to do with, another words I like top of the line beautifully crafted well thought out precision equipment, and I like innovative ideas, Henry Ford, John Deere, etc..etc.. I own a 21st Century turning lathe but have not used it long enough to form an opinion, I can see by looking at it that it was a innovative idea and of quality construction, and made in America by a true American which gives it three points right off the bat to me, had it been stamped out in China I wouldn't have taken a second look at it no matter how well it worked!! I had planned this winter to take my NT-4000 neck turner that does a good job turning necks but it is a pain to adjust, my Neilson, (not used yet ) and my new 21st Century (also not used), and my K&M and do a side by side honest comparison of the 4 turners and do a little review of my findings. I have learned a lot from you Mike and am always interested in your thoughts, I don't always understand what your trying to say to me but I listen and ask, this is no different I am interested in your method and tools of choice. Even cavemen had tools (toys) without them they could not have survived, without improving on them we still would be living in a cave spending our days foraging for foodmikecr said:
Wayne.
you need to add a PMA turner to that list ;D
AusFclass,
I did not originate the idea of going to the shoulder fast, and coming back slow. I read it, some years ago, in an article in PS by Dick Wright. The reason for that approach is that it keeps the neck pinned to the mandrel the whole time that the cutter is on the neck, and that....is the key to holding the tightest tolerances. It also achieves them without having to have a tight, wring on fit of the neck on the turning mandrel, which helps the heating issue a lot.
I will give you one more tip. When I make my first cut, taking most of the material off, I use an old Sinclair turner, with a stainless mandrel that I reduced in diameter, to give a better match with the old Sinclair expander. The fit on the turning mandrel was too tight, which tended to cause brassing, under the cutter. These days, I do my expanding with a K&M expander, to match the tool (with carbide mandrel) that I will make my final cut. The Sinclair turning mandrel is pretty loose in necks that were expanded with the K&M expander, sloppy, but since any runout is taken care of in the final cut, it does not matter, and the loose fit, prevents all heating and brass transfer to mandrel problems. It works well.
Boyd
I did not originate the idea of going to the shoulder fast, and coming back slow. I read it, some years ago, in an article in PS by Dick Wright. The reason for that approach is that it keeps the neck pinned to the mandrel the whole time that the cutter is on the neck, and that....is the key to holding the tightest tolerances. It also achieves them without having to have a tight, wring on fit of the neck on the turning mandrel, which helps the heating issue a lot.
I will give you one more tip. When I make my first cut, taking most of the material off, I use an old Sinclair turner, with a stainless mandrel that I reduced in diameter, to give a better match with the old Sinclair expander. The fit on the turning mandrel was too tight, which tended to cause brassing, under the cutter. These days, I do my expanding with a K&M expander, to match the tool (with carbide mandrel) that I will make my final cut. The Sinclair turning mandrel is pretty loose in necks that were expanded with the K&M expander, sloppy, but since any runout is taken care of in the final cut, it does not matter, and the loose fit, prevents all heating and brass transfer to mandrel problems. It works well.
Boyd
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