First attempt at neck turning (take 2)

[Brians356]

Why would you need a steeper angle than 40 deg. That is what the 308 family is isnt it?

What is your rhetorical question in reference to?

WRT 308 family: 20 degree shoulders. So that doesn't help explain your question.

???

 

[brokeasajoke]

I dont understand the retorical part. I honestly had 40 in my head. I am a super novice. Im curious as to why they wouldnt offer other angles than what it comes with. I emailed K&M earlier but havent heard anything back. I am neither trolling or just posting for the sake of it. I come here so others experiance canset me straight

 

[Brians356]

I dont understand the retorical part.

Not "rhetorical" in the strict sense. ("Why would anyone want to be rich?" is a rhetorical question, one to provoke discussion rather than elicit a specific answer.) There have been several neck turners discussed in this thread. So your question was rhetorical in the sense that was not directed towards a particular person or turning tool, i.e. I needed more context to respond.

I honestly had 40 in my head. I am a super novice. Im curious as to why they wouldnt offer other angles than what it comes with. I emailed K&M earlier but havent heard anything back. I am neither trolling or just posting for the sake of it. I come here so others experiance canset me straight

I am aware of no popular cartridge with a shoulder steeper than 40 degrees. So a 40-deg cutter will work for most any cartridge. Hornady's comes with a 45-deg cutter. If a turner came with a 20-degree cutter (ok for 308 Win etc) it would not work for a 22-250 or 6mm Rem, any PPC or BR cartridge, or a host of others including most Ackleys.

 

[brokeasajoke]

Ok thanks. One would think K&M would offer various cutter angles to "kiss" the shoulder. That seems to be the best method when approaching the shoulder with the cutter. I must refine my hillbilly thoughts and speech sometimes lol.

 

[brokeasajoke]

Sent K&M a email regarding cutter angles and discovered they will make a custom angle for you. They replied:

We have resisted the trend of late to match the cutter lead angle to the cartridge shoulder angle because we believe this can compromise the proper cut into the shoulder for doughnut control. Our cutter lead angle when placed in the same frame of reference as a shoulder angle is 50 degrees. This means the cutter lead angle is greater than pretty much any shoulder angle and this allows you to cut into the neck/shoulder interface as required for doughnut control while the lead angle cut transitions out of the shoulder. The proper technique is to make the material thickness at the neck/shoulder interface the same thickness as what you are turning the neck to. What most often happens when you match the cutter lead angle to the shoulder angle and cut into the neck/shoulder interface to the proper depth for doughnut control is you thin out the shoulder the full width of the cutter lead and we see this as undesirable. Most often guys think they need a different cutter lead angle because they read it on the internet but once they understand the true mechanics of why it is important to cut into the neck/shoulder interface and not the shoulder they agree.


Now, on rare occasion I have custom ground different lead angles usually for guys that are doing radical wildcat cartridge development with several forming progressions. If you would like try a different lead angle cutter I will grind it for you, there will be a $20 grind fee in addition to the base cutter price.


Thanks

 

[Dusty Stevens]

Ive never seen a need for anything but the one k&m installs. Like they said let it run into the shoulder for donut control and it only takes off about 1/4 the width of the cutter when it gets to where i like it. Any more than that is just thinning the shoulder

 

[Brians356]

Sent K&M a email regarding cutter angles and discovered they will make a custom angle for you. They replied:

We have resisted the trend of late to match the cutter lead angle to the cartridge shoulder angle because we believe this can compromise the proper cut into the shoulder for doughnut control. Our cutter lead angle when placed in the same frame of reference as a shoulder angle is 50 degrees. This means the cutter lead angle is greater than pretty much any shoulder angle and this allows you to cut into the neck/shoulder interface as required for doughnut control while the lead angle cut transitions out of the shoulder. The proper technique is to make the material thickness at the neck/shoulder interface the same thickness as what you are turning the neck to. What most often happens when you match the cutter lead angle to the shoulder angle and cut into the neck/shoulder interface to the proper depth for doughnut control is you thin out the shoulder the full width of the cutter lead and we see this as undesirable.

Thanks so much for posting that message from K&M! Having followed this and other threads, and thinking about it, I had already come to the same conclusion. I had wondered why having a single universal cutter angle seemed to be just fine for so long with most if not all of the neck turner makers.

When you think about it, you do not want to remove any material from the shoulder proper, thereby rendering it thinner, so why make the cutter angle match the shoulder exactly? If you are stopping short of shaving the shoulder proper, all the different angle does is change the shape of the notch almost imperceptively. The trick I suppose is to carefully control how deep of a notch to make at the neck/shoulder junction. Seems like stopping where a notch is just becoming visible would be about right to "make the material thickness at the neck/shoulder interface the same thickness as what you are turning the neck to" but we cannot determine that empirically unless we section a case to inspect the thickness of the wall at that notch. The notch might need to be a little deeper than what may seem prudent, I don't know.

 

[fourpower]

This is for a Rem 700 VS in 308 w/factory chamber. Thought I'd take a whack at neck turning. Trying to make the best possible ammo (and something new to play with). So I'm asking for critique and help before I move on to the lapua brass. I think I'm going to far into the shoulder. Not trying to completely turn neck but just true it up some. As you can see the cutter angle isn't close to the brass shoulder angle or maybe I'm doing something wrong. Didn't cut as far into the shoulder on top brass. Is pic size ok or too large? Thanks for help.View attachment 973701 View attachment 973702

I got tired of reading all the ways to neck turn and went and got a 21st century and never looked back! it does such a great job and all his cutters come with angles on the cutter. I found that if I turn for factory rifle I just take down too .013 and that has been working great and I don't have to do again. I have found some factory brass as bad as .016 off a side and when I take down to .013 it still only cleans up a little over 55% of the neck. so I at least neck turn once of factory and I anneal every other firing and my brass last a long long time!

 

[brokeasajoke]

Another email after further discussion.

"The final depth of cut into the shoulder is always difficult to describe because you have no external frame of reference other than the slight witness cut you should see on the shoulder. The best way to really determine the correct depth of cut is cut a case in half on the long axis after turning to make an inspection of the material thickness at the neck/shoulder interface. Usually a visible witness cut into the shoulder is your best judgement on the depth."