Squaring a press?

Discussion in 'Reloading' started by AJ Peacock, Jan 22, 2007.

  1. AJ Peacock

    AJ Peacock Well-Known Member

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    OK, so I've taken everyones advice on my Concentricity thread and removed the expander balls in my dies. I loaded some up and sure enough the concentricity improved.

    But what about presses? Does anyone pay attention to how square their reloading press is? I know that arbor presses and special dies are 'better', but what about the old standby single stage press?

    I recently bought an RCBS AmmoMaster 2 (large enough to handle the 338AM I have ordered). For those that aren't familiar with the press, there are 3 columns that hold the top of the press above the bottom of the press. It's not all cast as one unit like the RockChucker.

    [​IMG]

    I got to thinking 'what if those columns aren't exactly the same length? Or what if the holes that are drilled in the top weren't drilled EXACTLY the same depth? If either of those things happened, then the top would not be parallel to the bottom and would not be square to the ram. HMMMM??

    So, I just spent the last hour measuring its 'squareness' from the bushing on top of the press to the top of the ram.

    After countless measurements at full stroke, I've determined that the front of the hole is .005"-.007" further from the front of the ram than the back of the hole is from the back of the ram. The side to side is very close (probably around .001" if not closer). This would mean that the dies would actually slightly tilt backward.

    By carefully dressing the front support, I believe I can make the top square to the ram, but won't do it until I figure out the absolute best way to repeatably measure the differences.

    I've done some searches looking for a discussion about squaring a press etc. if it exists, I can't find it.

    Thoughts?

    Thanks,
    Don
     
  2. Chawlston

    Chawlston Guest

    [ QUOTE ]
    OK, so I've taken everyones advice on my Concentricity thread and removed the expander balls in my dies. I loaded some up and sure enough the concentricity improved.

    But what about presses? Does anyone pay attention to how square their reloading press is? I know that arbor presses and special dies are 'better', but what about the old standby single stage press?

    I recently bought an RCBS AmmoMaster 2 (large enough to handle the 338AM I have ordered). For those that aren't familiar with the press, there are 3 columns that hold the top of the press above the bottom of the press. It's not all cast as one unit like the RockChucker.

    [​IMG]

    I got to thinking 'what if those columns aren't exactly the same length? Or what if the holes that are drilled in the top weren't drilled EXACTLY the same depth? If either of those things happened, then the top would not be parallel to the bottom and would not be square to the ram. HMMMM??

    So, I just spent the last hour measuring its 'squareness' from the bushing on top of the press to the top of the ram.

    After countless measurements at full stroke, I've determined that the front of the hole is .005"-.007" further from the front of the ram than the back of the hole is from the back of the ram. The side to side is very close (probably around .001" if not closer). This would mean that the dies would actually slightly tilt backward.

    By carefully dressing the front support, I believe I can make the top square to the ram, but won't do it until I figure out the absolute best way to repeatably measure the differences.

    I've done some searches looking for a discussion about squaring a press etc. if it exists, I can't find it.

    Thoughts?

    Thanks,
    Don

    [/ QUOTE ]

    Hello again,

    You could shim it on the bottom or top until it is dead nuts on. But until you measure it under a full compressive loading, you won't actually know for sure how out of square it is.

    A quick test would be to screw in a die and then bring the ram to full contact. With pressure on the ram, use feeler gauges to see if there are any gaps between the ram (shellholder) and the die.

    FWIW, The case should still go into the die squarely since there is enough clearnace in the shellholder to account for the apparant lack of squareness. Hope this helps.

    James
     

  3. AJ Peacock

    AJ Peacock Well-Known Member

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    Chawlton wrote "A quick test would be to screw in a die and then bring the ram to full contact. With pressure on the ram, use feeler gauges to see if there are any gaps between the ram (shellholder) and the die."

    Great idea, so I slapped in an old 7mm FL die and it seemed to hit pretty square. I grabbed an old piece of brass, resized it. What do you know, on the concentricity gauge, it was less than .001" runout on the neck.

    I guess I will leave the press alone and try to find something else to 'worry' about until spring.

    Thanks,
    Don
     
  4. goodgrouper

    goodgrouper Well-Known Member

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    I don't like those kind of presses because of the problems you have discovered. You could try loading precision ammo on it and measuring it, but if it doesn't come out straight, I wouldn't put any more effort into it. Just sell it to a "quantity not quality" reloader and get yourself something else.
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    AJ Peacock,

    While I would agree that the Ammomaster is not the best press for making precise ammo on, it will certainly work, mine does just fine, in fact its just as consistant as my Redding Ultra Mag press which I personally feel is one of the better presses on the market for precision work.

    Trick is to use the right type of dies and set them up correctly.

    Your 338 AM will have a Hornady FL sizing die and a Forster Ultra BR seating die. With the Hornady FL die set up correctly you should be able to get neck run outs in the 1 to 2 range at most.

    With the Forster Ultra BR seating die with its slidling sleeve, the case is physically controled and held in axial alignment with the bullet as it is seated, the press really becomes nothing more then a method to apply pressure to the head of the case to seat the bullet as everything is held in alignment and can not get out of alignment for the most part.

    If your using conventional dies, yes you can see some issues with this press, with in-line sliding sleeve type dies, this is not really an issue to worry about.

    Just my opinion,

    Kirby Allen(50)