Placement of obv/rev dies in die presses irrelevant now?

Back in Autumn 2004 I started finding a lot
of Washington Iowa quarters with machine doubling
on the Obverse. Since the new coin presses lay the
dies on their side, does it really matter which
die is the theoretical "top" verses "bottom" ?

One of the reasons why I ask is because I don't
think that the mint considers the technical design
of the SHQ reverse (how the metal flows) and that
maybe, for the sake of better struck coins, they
put the Reverse die in the "top" position to insure a
better strike.

The Mint started playing around with inverted dies (obverse die as
anvil die) as early as 1992. It remained at nearly undetectable levels
until 1996. It was fairly common by 1998 and became the dominant
arrangement around 2000 or 2001. Since the middle of last year it
appears that all coins have been struck with inverted dies.

mikediamond wrote:
The Mint started playing around with inverted dies (obverse die as
anvil die) as early as 1992. It remained at nearly undetectable
levels
until 1996. It was fairly common by 1998 and became the dominant
arrangement around 2000 or 2001. Since the middle of last year it
appears that all coins have been struck with inverted dies.


During the time period you mentioned the mint was phasing out all of
the old Bliss presses and installing the new MRH series Schulers which
have the "inverted" die arrangment. Why did the mint decided to put the
obverse design on the collar (table) side, who knows? Does it really
matter as far as striking? not really. I use these same presses and
constantly change dies from the ram side to the table side and
vise-versa. The only thing that I have found concerning which die goes
on which side that it is truly advantageous is to have the die design
with the lower relief on the collar side, as that makes it easier for
the coin to eject.

The US mint has committed themselves to this "inverted" set up for the
long term. They have different die body designs for the obverse and
reverse dies. This makes it impossible to set a pair of obverse (or a
pair of reverse) dies in the press at the same time. So they would
have to re-tool all ot their presses to change back to "standard" die
set up. That would be rather expensive. Or I guess they could just
change which hub they use to squeeze the image on the obverse or
reverse die blanks. They might of have idiot-proofed that procedure as
well, so that may not be possible either.

Concerning the doubling that has been found lately (if indeed it is
machine doubling and not hub doubling) and standard vs. inverted die
set up...
The die holder design for the US mint dies is a 4 part unit that
"keys" the orientation of the die images, thus preventing rotations and
making die setting somewhat idiot proof. The problem I saw with the
design it that there were too many things that could go wrong with the
clamping of the die to the holder, thus allowing the die to become
loose, especially the reverse die, (the obverse die is somewhat
restrained by the collar).
I needed to have flexibility to move things around for all the custom
coin work we do, so when I installed my MRH Schulers I abandoned the US
mint die holder design and made our die holders a 2 part design where
it does not matter which die is on the ram or in the table. All my dies
are the same body design up to a certain coin diameter so I can place
them in the collar or on the ram at will. Also with only 2 parts there
are less things to break or come loose, but you do have to rely more on
set up person / press operator skills. I have not had any instances of
the dies coming loose or found any machine doubling.
Another possibility for doubling in the press is for the clamps that
lock the die holder assembly to the ram (or table)to come loose. I have
had this happen once and it scared the crap out of me to see the whole
ram side die holder assembly loose while the press was running at 750
strokes / min. I did not notice any doubling on the pieces made during
that incident, but I did notice that the centering was randomly moving
around.

I have been watching these recent doubling things with some interest,
as I use pretty much the same equipment. What I have failed to take
notice of is whether or not the doubling incidents predominately on the
reverse or obverse, or split evenly? This might help solve the mystery.
If anybody has been keeping tabs on this it would be interesting to
know.

Sean Moffatt
Operations manager
Hoffman Mint
www.hoffmanmint.com