Expander ball?

Discussion in 'Reloading' started by cornstalker, Feb 14, 2010.

  1. cornstalker

    cornstalker Well-Known Member

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    I have read tidbits here and there about guys removing the expander ball from their sizing dies. I understand the reason why due to the possibility that they will gall the case necks, or "bend" the neck creating runout.

    My questions is, does it take a bushing type or custom die to do this?

    Can you just take the expander ball out of any good sizing die and expect good results?
     
  2. winmagman

    winmagman Well-Known Member

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    Yes, you can take the expander ball out of any die. That will not however guarentee good results. Some dies will size the neck down a good bit more than needed relying on the expander to open the neck back up to where it needs to be. Without the expander in a die like this you will get an incredible amount of neck tension, that may be good may not, depends on what your rifle likes. The downside is you have no way to adjust that tension like you would with a bushing die.

    Chris
     

  3. nddodd

    nddodd Well-Known Member

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    Do they make different size expander balls like for instance .335 and .337 if so how could you go about getting some.

    Diddnt mean to highjack this thread just was curious and looked like a good spot to ask.


    Thanks,
    Nathan
     
  4. winmagman

    winmagman Well-Known Member

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    Nathan,

    That's a darn good question. I've never seen them, but I've never looked for them either. I'd be inclined to say no, but I can't say for sure.

    I know you can polish an expander down some to get more neck tension. But I don't know how you'd get less without going to a bushing die unless you have a way to polish the neck area of the die and still keep it perfectly round.

    Chris
     
  5. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Hey guys,
    looks like I'm a little late to this one, but it seemed worth stopping by. To begin, lots of folks don't use expander balls, and there's good reasons not to; they do bring about potential concentricity issues, and you are going to work the brass more in the neck area by dragging an expander ball back through it on the downstroke. On the positive (and yes, there is one), they do provide a positve control for uniform neck tension.

    I like bushing dies. They make it easy to adjust neck tension if you're not using an expander ball, but that presupposes that your brass has necks of a highly uniform thickness. If you're loading in relatively small lots, with brass that's been meticulously prepped, this shouldn't be a problem. As a High Power shooter, I tend to load in fairly large lots. I'm primarily a Service Rifle shooter, which means I don't get into the Bench Rest prep sort of insanity; Service Rifle brass doesn't live long enough to justify the effort. I do want uniform neck tension, though. My solution is to use the bushings, along WITH an expander, just to ensure that everything's consistent across the board. I prefer the carbide expander balls when they're available, but a polished steel expander works too. In use, I select a bushing that, with that lot of brass, provides just enough tension that I can slightly feel the passage of the ball back through the neck. This means a little experimentation and measuring on your part, but hey, that's what it is. With many non-bushing dies and the standard expanders they arrive with, the neck gets sized down so much that you will have to fight to get the expander back through the neck on the upstroke. This is an invitation to all kinds of headaches, and not the way you want to go.

    If you're serious about this, you're going to wind up honing the neck out to a size that will put the minimal sizing on the brass, while still bringing it down far enough to get the neck tension you want. That final dimension can, of course, be controlled by the expander. In the case of the steel expanders, this can be done with some patience, a good micrometer, and drill press and some emory or crocus cloth. On the carbide balls, we're pretty much at the mercy of the manufacturers there, unless you're adept at working the stuff. I'm not, so the term SOL comes to mind.

    Yeah, there are some options here, so don't write them off too quickly. Hope that helps, or gives you something else to think about.

    Kevin Thomas
    Lapua USA
     
  6. phorwath

    phorwath Well-Known Member

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    You ever honed the neck out of a hardened resizing die? If so, how did you go about doing that?

    I just spent four evenings honing out the body of a RCBS full length resizing die so it wouldn't work my brass so much. I used a brass bore brush wrapped in 3M Wet-Dry sand paper, turn by a battery operated drill. All that did was polish the die surface. Next I tried a coarser grade of 3M Emery Cloth. More polishing. Next I coated the Emery Cloth with some silica carbide valve grinding compound - 280 grit. This started to remove some of the hardened steel - painfully slowly. Then I applied 120 grit silica carbide valve grinding compound. After about 2 hours of lapping with the battery powered drill, I was able to remove about 0.002" over the sides of this FL resizing die.

    Anyone that says you have to clean your brass cases carefully so as to not scratch the resizing die is full of it as far as I'm concerned. Once those reloading dies are heat treated, they are tough - tough - tough.

    This leave me wondering - what type of machining equipment or tools are used to open up a heat-treated neck on a full length resizing die?
     
    Last edited: Feb 19, 2010
  7. winmagman

    winmagman Well-Known Member

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    I wouldn't mind finding that out either, I've got a sizing die that is so tight in the neck I can just about lift my bench off the floor pulling the expander ball back through.

    Chris
     
  8. bigngreen

    bigngreen Well-Known Member

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    I have seen my dad do a couple necks on dies and the first one took for ever but what he ended up doing was splitting a dowl and sliding a piece of wet/dry in the slit. Turned it with a drill in the sink with water flooding it, the water was the key. I think he took out a few thou in about 45 min.
    I have though about a casting of some sort or slitting a case full length then inserting a piece of wet/dry for turning the body.
     
  9. Moman

    Moman Well-Known Member

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    I've sent three dies back to Forster over the last couple of years to have them honed. They charge $10 per die. The first one I sent was for my 300 WM. A loaded case measured .335 at the neck and they honed it to .332. It made a big difference in not overworking the brass. The only drawback, which doesn't concern me, is if you were to use thinner brass later on, the die wouldn't close the mouth down far enough for the expander to do its job.

    I believe that this process helps to eliminate some of the runout caused issues from using an expander.
     
  10. Winchester 69

    Winchester 69 Well-Known Member

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    For those interested in opening their FL sizer up some to minimize brass working, Forster offers for their dies a service at a nominal price of honing the die to your spec. Shipping runs the price up a bit, but you get a precision job without expending hours on a less precise process.

    I don't believe it's been brought up here, but the other contention with an expander is the possibility of misaligning the brass' neck because of expander misalignment. Using a floating design is one approach. Another is to introduce some compliance in the stem. Some simply loosen the stem in the die. I use a fat O-ring under the adjusting nut on my sizers that holds adjustment while allowing the case neck to center the expander button being drawn through it.
     
  11. Kevin Thomas

    Kevin Thomas Well-Known Member

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    I cheated. One of the advantages of working in a shop with a fully equipped and staffed machine shop right there at the top of the stairs. I gave it to them, told them what I wanted and it would shortly return to the range done to whatever I'd specified. It was a really good system for me, and one of the few things I miss these days! Now, sounds like Forster's the ticket. That, or just start with a bushing die from the word go.

    Kevin Thomas
    Lapua USA
     
  12. phorwath

    phorwath Well-Known Member

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    Thanks Kevin. I thought maybe you had a secret that could be shared. The secret is evidently having the tool and die guys as a buddy so they can use their elaborate tooling to get the job done precisely, accurately, and efficiently.

    I knew about Forster's service but they didn't offer a die in 280 RCBS Improved - 30 degree shoulder so I couldn't take advantage of their customization service.

    I still can't believe how tough my RCBS die was to open up just a couple thou. The heat treatment hardening of those dies is impressive.
     
  13. Bart B

    Bart B Well-Known Member

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    I've cut a slot in the end of a 1/4th inch wood dowel and put 400 grit emery paper on it to lap out .308 Win. and .30-.338 dies. Chucking the stripped die in a lathe's headstock bottom out then wetting the paper, running it in and out a few times, using a hole micrometer to check diameter, it's worked just fine. It usually takes only a few thousandths more in neck diameter to get it right. About 1 to 3 thousandths smaller than loaded round neck diameter depending on how much grip one wants on the bullet. Be sure to clean all the grit out of your die before you start using it.

    Nowadays, RCBS and Redding make full length sizing dies that even accept each others bushings so one can get one just right for your case neck's wall thickness and bullet diameter. Coupled with a Redding shell holder of the right height so your fired case shoulders are set back exactly 1 thousandth when the loaded die bottoms out on it and you've got all the right stuff.

    Full length sizing cases in such a die makes for much straighter necks. It's important to minimally size fired case bodies. No more than 2 or 3 thousandths reduction in diameter is about right. If you chambers are on the big side, you can get your die's body lapped out or send a few fired cases to folks that make them for you.
     
    Last edited: Feb 22, 2010
  14. LRHWAL

    LRHWAL Well-Known Member

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    phorwath,

    Forster do offer custom dies that are not on the regualr list. I asked and they quoted me a pretty high price (for Forster which is generally really well priced IMO; became similar to Redding type S).

    You may want to drop an e-mail and ask.