I am just getting ready to learn how to neck turn cases in a serious way and I noticed K andM or Cen 21, etc. offered cutter blades in different angles so as to properly cut into the shoulder. It never occurred to me to even think of this. Is there a simple chart somewhere that shows the different shoulders on brass by caliber so as to know which cutter angle is correct for the caliber? I assume we must just look at the Case dimensions in the loading manuals? I’m shooting 6XC which will be different then my 308///or I just buy a cutter preset for each caliber so I only have to tune it once? This is beginning to get more complicated then it needs to be....
Neck Turning - carbide cutter angle?
- Thread starter Baer45
- Start date
K&M and 21st cent are great neck turners, i know 21st have a chart on their site stating which angle cutter you need for the caliber you have.
KMart
Gold $$ Contributor
Personally i like this one the best.
http://www.pmatool.com/neck-turning-tools/
The cutter.angle should match the shoulder angle. This allows you to slightly cut into the shoulder thining the brass that can become neck. Helps to reduce donuts.
http://www.pmatool.com/spare-carbide-neck-turning-tool-cutter/
http://www.pmatool.com/neck-turning-tools/
The cutter.angle should match the shoulder angle. This allows you to slightly cut into the shoulder thining the brass that can become neck. Helps to reduce donuts.
http://www.pmatool.com/spare-carbide-neck-turning-tool-cutter/
6XC is the cartridge. It's 24 caliber.
You don't actually want your cutter angle to match the shoulder angle while cutting. If it did you would likely cut too much brass from shoulders. You want the the cutter angle higher than the shoulders affected.
This is one several reasons to turn necks on NEW brass, as these shoulders are not yet reaching full fire-formed angle, and have not been sized up yet (to same or higher caliber).
Don't go stupid with this,, 30deg cutter angle for new brass shoulders, to be formed to 30deg, is fine.
So is 40deg, just take care not to cut too deep. 20deg would be wrong, as it will dig in further down the shoulders.
Inherent to it's manufacture, all cases are thicker at webs than case mouths, tapering in this thickness. So brass is thicker in shoulders than in necks, and even within necks, near shoulder junction to mouths.
Neck-shoulder junction expands on fire-forming, to become the lowest part of necks. This, moving thicker shoulder brass into neck area.
You're only cutting onto neck-shoulder junction (just a touch)(~1/32") to prevent this donut condition created during fire-forming. One benefit from neck turning.
Read this to see a bunch of excess cutting: http://bulletin.accurateshooter.com...-your-cutter-angle-for-improved-neck-turning/
For better, consider these pics:
You don't actually want your cutter angle to match the shoulder angle while cutting. If it did you would likely cut too much brass from shoulders. You want the the cutter angle higher than the shoulders affected.
This is one several reasons to turn necks on NEW brass, as these shoulders are not yet reaching full fire-formed angle, and have not been sized up yet (to same or higher caliber).
Don't go stupid with this,, 30deg cutter angle for new brass shoulders, to be formed to 30deg, is fine.
So is 40deg, just take care not to cut too deep. 20deg would be wrong, as it will dig in further down the shoulders.
Inherent to it's manufacture, all cases are thicker at webs than case mouths, tapering in this thickness. So brass is thicker in shoulders than in necks, and even within necks, near shoulder junction to mouths.
Neck-shoulder junction expands on fire-forming, to become the lowest part of necks. This, moving thicker shoulder brass into neck area.
You're only cutting onto neck-shoulder junction (just a touch)(~1/32") to prevent this donut condition created during fire-forming. One benefit from neck turning.
Read this to see a bunch of excess cutting: http://bulletin.accurateshooter.com...-your-cutter-angle-for-improved-neck-turning/
For better, consider these pics:
Super help everyone..I think I’ve got it clear in my head for the moment anyhow. I have a Sinclair cutter and Century 21 new. I am going to go with the Century 21 because I like the way it works and I already ordered the motorized attachment. That aside, the K and M cutter head turning mandrel is a smart piece of work. I’m clear on just touching the shoulder and no more. I’m using new Lapua brass which can be tight in my chambers. Do you resize your new-brass first or just run a mandrel down the inside to move imperfections out for the cutter to clean up?
Keep in mind that it takes extra efforts to screw up neck turning.
Just run correct/matched system expander mandrel through new/untouched necks, and turn them on the matched turning mandrel. Focus on that.
Don't size anything, trim anything, chamfer, or grind away at the innards with do-dads. You'll be better to do non-neck turning things -after neck turning.
Just run correct/matched system expander mandrel through new/untouched necks, and turn them on the matched turning mandrel. Focus on that.
Don't size anything, trim anything, chamfer, or grind away at the innards with do-dads. You'll be better to do non-neck turning things -after neck turning.
Hmmm??? The new batch of .308 Lapua brass I have measures within .001 base to neck, but the overall length has a variance of as much as .004 (maybe a little more sometimes). My neck turning set up is set with a stop for a case length of 2.005. If I don't trim them first the the cut into the shoulder at the neck-shoulder junction won't be uniform. In order to get the interior of the neck as uniform as possible I run then through a Lee Collet die first; followed by running the expander mandrel before trimming with a Tri-Way trimmer which uses the shoulder as a stop to get uniform case length. This way, I get a consistent neck-shoulder junction to mouth measurement for a uniform cut at the neck-shoulder junction. I don't get that uniformity if I don't do those things you say don't need to be done . . . so??? Is getting that uniformity just a waist of my time?
I think doing your trimming first has more to do with the way your neck turner brand works..PMA?? However, I still see the merit in what you are saying. I could see an argument for trimming first to Make sure my case head is square going onto the mandrel stop. I also can’t see any reason not to push any imperfections to the outside with a mandrel down the pipe prior to neck sizing so they can be removed. A lot of this is determined by the setup of the make of neck turner. I’m not a BR shooter so Mikekr’s point might be spend more time shooting and less in adding extras to neck turning where the difference on target is minimal to his “game”...I won’t know what right for me until I do it, but all this info is helpful. Thanks
dcali
Bullet Maker
Trimming (and sizing) first makes sense, but I don't. Sometimes I wonder if I'm getting things as consistent as I could be, but it just intuitively seems like such a minor thing that I don't worry about it. We're only talking about a few thous of brass that has been turned ever so slightly more. And it's not even brass that touches the bullet.
Trimming and sizing do not make sense until it's time to do so. That would be down the road a ways from neck turning.
#1 you should trim necks w/resp to chamber end clearances only, which are affected with fire-forming.
If you just grind away to make em all the same length before firing(which will draw necks back even further), you'll end up with huge chamber end clearances, and your case OALs will still vary at that point (until trimmed again). You don't need to use a turner stop, just watch what you're doing, and let fire-forming hammer at your results.
#2 the expander mandrel does a fine enough job to push new brass thickness variance outward -and establish correct fit to the turning mandrel. Any other action will just screw this up..
Another thing; New brass is not straight, don't worry about it. Fire-forming will take care of that.
So when turning new brass it will wobble.
When something isn't straight you float it, and basic neck turning includes holding the turner body in your hand (floating). With this, the brass can wobble all over hell, and your turning will still be fine. That is, unless you try to get smarter than basic neck turning, and add a bunch of unnecessary factors..
Neck turning is basic stuff. It's easy. After neck turning,, that's when you can go crazy with all kinds of stuff.
#1 you should trim necks w/resp to chamber end clearances only, which are affected with fire-forming.
If you just grind away to make em all the same length before firing(which will draw necks back even further), you'll end up with huge chamber end clearances, and your case OALs will still vary at that point (until trimmed again). You don't need to use a turner stop, just watch what you're doing, and let fire-forming hammer at your results.
#2 the expander mandrel does a fine enough job to push new brass thickness variance outward -and establish correct fit to the turning mandrel. Any other action will just screw this up..
Another thing; New brass is not straight, don't worry about it. Fire-forming will take care of that.
So when turning new brass it will wobble.
When something isn't straight you float it, and basic neck turning includes holding the turner body in your hand (floating). With this, the brass can wobble all over hell, and your turning will still be fine. That is, unless you try to get smarter than basic neck turning, and add a bunch of unnecessary factors..
Neck turning is basic stuff. It's easy. After neck turning,, that's when you can go crazy with all kinds of stuff.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.