Neck Turning Doughnuts?

[High Binder]

I'm just getting into neck turning and I keep hearing about a doughnut being created from the process but after watching everything on Youtube and searching the net, I can't really find anything that explains what the doughnut is and how it is created and avoided?

Any help would be appreciated.

 

[Short Round]

Re: Neck Turning Doughnuts?

Well I don't think I can tackle all that with competence.

The doughnut is a thickened band at the junction of the shoulder and neck. The issue is if it's big enough it fills the chamber neck and you don't get a proper bullet release as there is no where for the brass to expand to. It's eliminated by inside reaming or by expanding followed a neck turning to uniform the neck.

I'm a newb at turning. My 3 and 4 times fired RP .260 brass had donuts. Previously I lightly turned the to uniform the neck. I was actually suprised at how much brass was shaved on the second go round.

Oh, to back up. To check for your donuts. Take your fired brass and insert a bullet into the un resized neck. If you feel it drag at the neck/shoulder junction, you likely got donuts.

I also have an experimental run of .308 brass sized to .260 rem. I had to neck turn them and after the first firing, I annealed and then I FL resized and returned the necks. It looked like donuts there too.

hope this helps somewhat.

 

[Victor N TN]

Re: Neck Turning Doughnuts?

Personally I ream the donuts from fired but unsized cases. You can get a bullet sized HSS reamer fairly cheaply. MSC or any other industrial supply can get you what you want at a decent price. Doing it this way is cheaper and I feel, more effective, than turning the necks again.

 

[High Binder]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Short Round</div><div class="ubbcode-body"> It's eliminated by inside reaming or by expanding followed a neck turning to uniform the neck.
</div></div>

So the doughnut is on the inside, interesting. How does the process of neck turning create the doughnut? And typically how much larger is the doughnut than the rest of the neck i.e. how much will I end up knocking out of the doughnut with a HSS/carbide reamer?

 

[High Binder]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">Personally I ream the donuts from fired but unsized cases. You can get a bullet sized HSS reamer fairly cheaply. MSC or any other industrial supply can get you what you want at a decent price. Doing it this way is cheaper and I feel, more effective, than turning the necks again. </div></div>

Vic, would this

http://www.precisionreloading.com/mm5/me...ode=NECK_TRN_KM

be a good option for removing doughnuts while neck turning?

 

[DRAM40A1]

Re: Neck Turning Doughnuts?

The donut isn't created by turning. It forms after multiple firings pushes brass forward from the shoulder into the neck.

 

[Victor N TN]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shot In The Dark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">Personally I ream the donuts from fired but unsized cases. You can get a bullet sized HSS reamer fairly cheaply. MSC or any other industrial supply can get you what you want at a decent price. Doing it this way is cheaper and I feel, more effective, than turning the necks again. </div></div>

Vic, would this

http://www.precisionreloading.com/mm5/me...ode=NECK_TRN_KM

be a good option for removing doughnuts while neck turning?

</div></div>

That'll do it. But this is what I use: http://www1.mscdirect.com/CGI/GSDRVSM?PACACHE=000000143246414

You can hunt down inports if that's too expensive. Or carbide tipped if you want it.

 

[Shady_Jay]

Re: Neck Turning Doughnuts?

cutting slightly into the shoulder junction helps reduce and/or eliminate them

 

[High Binder]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">cutting slightly into the shoulder junction helps reduce and/or eliminate them </div></div>

Ah, that makes since because it creates a void on the OD where the doughnut on the ID is pressured into.

 

[High Binder]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">

That'll do it. But this is what I use: http://www1.mscdirect.com/CGI/GSDRVSM?PACACHE=000000143246414</div></div>

Vic, do you ream, neck-turn, resize, ect? Or do you do it in a different order? Thanks Vic!

 

[High Binder]

Re: Neck Turning Doughnuts?

Anyone following this thread might find this interesting.

http://home.comcast.net/~jesse99/doughnuts.html

 

[Victor N TN]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shot In The Dark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">

That'll do it. But this is what I use: http://www1.mscdirect.com/CGI/GSDRVSM?PACACHE=000000143246414</div></div>

Vic, do you ream, neck-turn, resize, ect? Or do you do it in a different order? Thanks Vic! </div></div>

Using fired but not sized cases I spin the cases in a 1/2" keyless chuck on an 18 volt Dewalt drill. I hold the reamer in a tap holder. I use oil to keep the flutes of the reamer lubricated. Then wash out with alcohol and continue with your process as usual. Sizing, trimming...etc Whatever your checklist is for what you do.

I only turn the necks one time. I have an instrument to check case neck thicknesses. If after being annealed, the necks look or measure thick I will turn them again. I do the whole original batch at one time. But not until they have been annealed. Normally I can get several "soft" load cycles before needing to anneal.

 

[rasp65]

Re: Neck Turning Doughnuts?

Here is another article about donuts: http://www.6mmbr.com/260AIforming.html

 

[High Binder]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shot In The Dark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">

That'll do it. But this is what I use: http://www1.mscdirect.com/CGI/GSDRVSM?PACACHE=000000143246414</div></div>

Vic, do you ream, neck-turn, resize, ect? Or do you do it in a different order? Thanks Vic! </div></div>

Using fired but not sized cases I spin the cases in a 1/2" keyless chuck on an 18 volt Dewalt drill. I hold the reamer in a tap holder. I use oil to keep the flutes of the reamer lubricated. Then wash out with alcohol and continue with your process as usual. Sizing, trimming...etc Whatever your checklist is for what you do.

I only turn the necks one time. I have an instrument to check case neck thicknesses. If after being annealed, the necks look or measure thick I will turn them again. I do the whole original batch at one time. But not until they have been annealed. Normally I can get several "soft" load cycles before needing to anneal. </div></div>

10-4, thanks Vic!

 

[Clark]

Re: Neck Turning Doughnuts?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> K & M has specially designed a carbide pilot that has four flutes for removing the “dough-nut” that is located at the neck-shoulder junction of a case. Removing this extra material aids in a consistent high volume flow of powder gas. This pilot will also cut the extra material out of this area if you have changed the neck to a different caliber. Works while you neck turn so you will not have to perform a separate operation. </div></div>

I am not worried about gas flow.
The brass works fine until I try to seat a bullet deeper than the base of the neck.
The problem for me is the doughnut interfering with a deep seated bullet.
That makes a discontinuity in bullet seating force.
That makes a bulge in the loaded ammo.
That deforms the bullet.

I don't expect laminar gas flow.