Neck turning

[Straightshooter1]

The stress of neck turning affects how well the brass fits on the mandrel, and the amount of stress depends upon how much material is being removed. After turning the inside diameter will be larger than when you start.

When I'm prepping competition brass I use two neck turning tools, one for roughing and one for just a light finishing pass. The finishing tool has a mandrel that is 0.0005" larger than the one I use for roughing. This compensates for the growth that occurs during roughing and results in more consistent wall thickness.

How much removal (.001, .0015, 002 . . .???) will cause something like .0005 larger inside diameter?

I take up to .0015 off the necks of my .308 and 6.5 PRC cases and don't see any kind of growth as you describe and get very consistent wall thickness (like within less than .0002). . . at least, according my my tools (e.g. Mitutoyo caliper and micrometer). I guess you have tools that measure better than mine to detect this phenomenon???

 

[338 dude]

Guys, do I need a lathe to consistently neck turn? I compared the tools and Hornady, 21st century offer a lathe.
Will I get repeatable results using a KM neck turning tool in one hand and case in a cordless drill in another? It seems to me as lacking stability. Is it enough for neck turning for precision shooting?

Have not watched the video but that has been my thoughts for several years now how can you be steady holding it in your hands I use a Hornady neck turning tool because it is like a mini lathe I believe I get a better job with it

 

[JFrank]

Have not watched the video but that has been my thoughts for several years now how can you be steady holding it in your hands I use a Hornady neck turning tool because it has like a mini lathe I believe I get a better job with it

I was thinking the same thing but as it turns out It’s not that tough, the mandrel holds the case in line.

 

[longbow]

I use a cheapo variable speed mini wood lathe ,with a Jacobs chuck and Lee universal three jaw chuck.Going on 30 years! Works for me....

 

[PracticalTactical]

How much removal (.001, .0015, 002 . . .???) will cause something like .0005 larger inside diameter?

I take up to .0015 off the necks of my .308 and 6.5 PRC cases and don't see any kind of growth as you describe and get very consistent wall thickness (like within less than .0002). . . at least, according my my tools (e.g. Mitutoyo caliper and micrometer). I guess you have tools that measure better than mine to detect this phenomenon???

I go by feel. When I start turning, the case is snug to the mandrel, but when I am done, it is lose.

I can make the neck thicker or thinner by which direction I push the case, meaning toward the cutter or away from it. The difference is the result of the inside diameter changing under the stress of cutting.

The second pass is just a very light clean up and it makes them just that much more consistent.

Now, I don't know what you are using to drive the case... I use something I bought long ago from Sinclair, back when it was ran by real shooters. Then Bob from Viper Bench Rest made me a nice knurled collet to increase the diameter and make it faster to clamp and unclamp. I run it in a variable speed drill for low volumes and in the drill press running slow when doing large runs.

One trick I will share is that I use a block of steel with a blind hole drilled in it that I put a few drops of oil. I dip the neck into it so some oil gets on both the inside and outside before cutting. Every now and then I will add another drop or two. It just helps provide better control over how much oil gets on the case and its more convenient than dripping from the bottle every case.

 

[Tokay444]

How much removal (.001, .0015, 002 . . .???) will cause something like .0005 larger inside diameter?

I take up to .0015 off the necks of my .308 and 6.5 PRC cases and don't see any kind of growth as you describe and get very consistent wall thickness (like within less than .0002). . . at least, according my my tools (e.g. Mitutoyo caliper and micrometer). I guess you have tools that measure better than mine to detect this phenomenon???

It’s brass. Resize it, and the ID is smaller again.

 

[Clark]

I cut a new mandrel each time so I know it is concentric with the lathe spindle.

 

[snoopy001]

The best solution is only the IDOD machine if affordable maybe in future , it is much more important to to turn inner side of the neck as the bullet stay in contact with.The outside turning only make little sense at all.

 

[BartsBullets]

How much removal (.001, .0015, 002 . . .???) will cause something like .0005 larger inside diameter?

I take up to .0015 off the necks of my .308 and 6.5 PRC cases and don't see any kind of growth as you describe and get very consistent wall thickness (like within less than .0002). . . at least, according my my tools (e.g. Mitutoyo caliper and micrometer). I guess you have tools that measure better than mine to detect this phenomenon???

Turn your case necks to your desire dimensions and forget about the rest of the bull$Hit. Do them all the same then adjust neck tension with bushings.

 

[338 dude]

The best solution is only the IDOD machine if affordable maybe in future , it is much more important to to turn inner side of the neck as the bullet stay in contact with.The outside turning only make little sense at all.

But if you use an expanding mandrel the theory is it will push any imperfections to the outside where is a little concern

 

[snoopy001]

But if you use an expanding mandrel the theory is it will push any imperfections to the outside where is a little concern

Erik made a video concerning IDOD with the owner of the patent who explaines exactly the advantage by turning in and outside ,have a look there and you will revise your opinion.
regards snoopy.

 

[338 dude]

Erik made a video concerning IDOD with the owner of the patent who explaines exactly the advantage by turning in and outside ,have a look there and you will revise your opinion.
regards snoopy.

The IDOD is definitely the best of the best I do what I can with what I have for now. I do have an amp annealer eventually I will have an IDOD neck Turner as well

 

[Tokay444]

Turn your case necks to your desire dimensions and forget about the rest of the bull$Hit. Do them all the same then adjust neck tension with bushings.

Amen.

 

[jackieschmidt]

Turn your case necks to your desire dimensions and forget about the rest of the bull$Hit. Do them all the same then adjust neck tension with bushings.

There you go again, Bart. Injecting common sense into the discussion.

 

[Tokay444]

Guys, guys. He’s, “got enough gold medals on the wall to know.” Also, he’s this guy…

 

[PracticalTactical]

Guys, guys. He’s, “got enough gold medals on the wall to know.” Also, he’s this guy…

Hey big mouth... Come on up to Ottawa and shoot the provincials with us some time. We can quickly prove who is ahead of the curve.

Just because you don't have the intellectual capacity to understand the benefit of this approach does not mean there isn't one.

 

[Tokay444]

I have the intellectual capacity to know that is the ID if my brass opened up slightly during neck turning, I don’t need a larger mandrel for a second pass, because I have a sizing die.

 

[jimmymac]

This is a simple, repeatable process. If you are getting variation in your neck wall thickness, then you are doing something wrong or your equipment is not up to snuff, or both.

 

[Tokay444]

Imagine having the intellectual capacity to understand that.

 

[tovaert]

My understanding is that every cartridge brass neck that is re-sized with a bushing will spring-back slightly, which puts the neck in a state of residual tension, and vice-versa for a neck that was expanded with a mandrel. If the residual stresses are not annealed away, then removal of material can change the ID, however, the amount may not be easily quantified for a number of reasons including the possibility that the magnitude may be on the order of the surface roughness. I got into it because I had to reduce neck wall thickness in some Lapua .223 brass, as the clearance between the neck and barrel throat area was only about 0.001" or so, not a good idea per se, and I had problems chambering mag-fed 90 gr Bergers in a 6x45 AR. BTW...I built a simple neck peeler, which I believe is a bit better than neck turning, but that's a different discussion.