Neck turning

Discussion in 'Reloading Forum (All Calibers)' started by 2343, Mar 25, 2020.

  1. 2343

    2343 Silver $$ Contributor

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    Which is right? I bought the Pma 40 degree cutter out of curiosity and I'm I getting cuts further down the shoulder. I've never turned brass down this far and wondering what if any the benefit is? Before this I've always just made a slight cut into the shoulder. Is this acceptable or am I just ruining brass?
     

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  2. jepp2

    jepp2 Gold $$ Contributor

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    Too much. Should only extend ~0.030" on the shoulder, and not enough to feel where it ends with your finger nail.
     
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  3. fgcook

    fgcook Gold $$ Contributor

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    I’ve seen them go that far to remove any donut in that area? But I am new at turning as well.
     
  4. Bill Norris

    Bill Norris Gold $$ Contributor

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    Looks a little heavy to me but some may differ.
     
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  5. bozo699

    bozo699 Gold $$ Contributor

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    It is a little heavy but you haven’t ruined it.
    When you fire it,... it will smooth out. Save that piece for fouling or sighters
    Wayne
     
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  6. Lone Hunter

    Lone Hunter Silver $$ Contributor

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    May be an optical illusion but it looks like you are turning too fast also. It looks like grooves where you turned and for me you went too far into the shoulder. I don't think you ruined them, Shoot them.
     
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  7. bozo699

    bozo699 Gold $$ Contributor

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    I thought the same thing I had some the other day looked just like it had to do a redo on 2or 3 got in a hurry I guess. But as you said might me optical illusion
    Wayne
     
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  8. Willie

    Willie Gold $$ Contributor

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    It's always been a crap shoot to determine how far to go into the shoulder, as it's very difficult to measure in that area, if not impossible.

    I tried a 40* cutter to match the shoulder for awhile, but went back the 50* cutter that I first started using. At that time, it was the only angle that K&M offered. It has worked well for any shoulder angle I need, be it parent case or the formed case.

    The OP's picture looks like it went a bit too far, but he could split the case and try to measure the shoulder on that case, if he's doubtful.
     
    Last edited: Mar 26, 2020
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  9. McHaggis

    McHaggis

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    Yep. Too deep into the shoulder. I normally use a cutter about 5° more than the shoulder angle so I can blend the cut in yet still cut into the shoulder enough.
    Try another one but only go 1/2 to maybe 2/3’s as deep into the shoulder.
     
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  10. BoydAllen

    BoydAllen

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    Related funny story: I have a Stiller turner and used it to redo some previously turned PPC necks. I had not paid much attention to the angle and its width. (I have a number of different turners.) Turns out that it is 30 degrees (the same as the PPC) and wide enough to sweep the entire shoulder, solving the problem of blending quite handily.
     
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  11. 1shot

    1shot Silver $$ Contributor

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    My thoughts exactly.

    Lloyd
     
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  12. 2343

    2343 Silver $$ Contributor

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    Thanks for the info guys. Looks like I'm going to go back to the old carbide.

    Thanks Wayne
     
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  13. Mulligan

    Mulligan Gold $$ Contributor

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    I think I would adjust the turning mandrel so the cutter doesn’t cut so far into the shoulder. The neck shoulder junction looks good and clean, its just biting a bit far into the shoulder.
    CW
     
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  14. jackson1

    jackson1 Silver $$ Contributor

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    Before any neck turning, I trim my necks to the same length. Easy to hold +/-0.001 with my Wilson trimmer, then internal chamfer, again using my Wilson trimmer. New brass find the shortest example. Could not hold those tolerances with my old RCBS trimmer. Set up my turning tool to cut a few thousands into the neck shoulder area, as I have read, this will prevent donuts. My problem is, I seat so close to the lands, that I have never noticed a problem with donuts. Making repeatable cuts (precise or the same) is my goal. Maybe somebody could test the different theories on cutting depths.
     
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  15. 338 dude

    338 dude Gold $$ Contributor

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    you want to try to match the shoulder angle of whatever cartridge you were shooting but as said on this post I can see the edge where it stopped cutting the shoulder you were going a little too deep
     
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  16. foxguy

    foxguy

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    2343,

    I will just recap what others have already shared.

    I see theses are fired cases, Insure the case length is the same on all of the cases you want to turn, (how far a PMA turner turns into the neck area is determined by the relationship of the turning mandrels adjustment in relationship to the cutter. the case necks all need to be trimmed to the same length in order to get the same cut depth into the shoulder area.) if you should have to trim the case neck lengths chamfer the inside and out.

    Looks like the Turning Mandrel could just be adjusted out a little and you would be good to go.
     
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  17. 47WillysGuy

    47WillysGuy Gold $$ Contributor

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    I match the cutter angle to the case shoulder angle and make a light cut (0.001" or more) into the shoulder. I touch the shoulder with the cutter, then lower the mandrel a scooch(very precise measurement) more. I figure if the neck wall thickness is 0.015" so should the shoulder wall be. So taking 1-2 thousands into the shoulder wall is fine for me. I've got 10 reloads on the brass and have not blown a neck off yet.

    I've cut cases a second time after 2-3 firings and found the area between the shoulder and the neck thickening from brass moving towards the neck. If your worried, cut a case in half the long ways and inspect.

    Benefit is no donut.
     
  18. dogdude

    dogdude Egan O'Brien Gold $$ Contributor

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    I use a K&M 38 degree cutter on my WSM brass..(35 degree) cuts very nice..after trimming too the exact length..Very important.;)
     
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  19. Ackman

    Ackman Silver $$ Contributor

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    I'd use a cutter with an angle the same or as close to shoulder angle as possible. And with a decent sized radius, like the Sinclair. Just barely kiss the shoulder but don't go into it. That one case is way too much, the other one is better but still a little bit more than I'd do.
     
  20. Mulligan

    Mulligan Gold $$ Contributor

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    This is very good advice..
    The shoulder area was much thicker than I thought.
    CW
     

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