How does a "Broadstrike" occur on modern coining presses?

WoodenJefferson

The Mints are utilizing horizontal stroke coining presses for our circulation coinage, my question is, how does a broadstrike occur on a press designed as such? (ie. no mechanical finger failure to extract the struck coin as used on the vertical strike Bliss coining presses) On the Schuler press, the blanks are gravity-fed vertically into the press so that they’re "standing up" when they receive their blow from the hammer die. On a normal up-and-down press the hammer die is usually the obverse die ("heads side") and the anvil die is usually the reverse ("tails" side), but on the Schuler horizontal press the hammer die is usually the reverse die.

What fails operationally to create a broadstrike or a die cap, help me to understand.

Unknown

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Broadstruck

I feel that most errors that occur on the Schuler presses are initial strikes during die set-up, but more then the newer vertical presses it's the screening process that has eliminated errors escaping into the marketplace since 2002. I have seen a couple 2007 B/S Pres $1'S and some Denver minted 2007 Dime and Quarter die caps which where surprising, but I'm not sure if they where struck on Schuler's, or if the mint's still has a few older presses operational? Although it seems that Lincoln errors have dried up there are post 2002 Broadstrike Roosevelt's on the marketplace, yet any error greater then 10% O/C or Saddle Strikes are nonexistent.

johnny9434

yeah, what realone said, or the guys just coming back from lunch. either or

Broadstruck

<< <i>A mint emplyee who desires to earn extra money by intentionally creating said error and then smuggling it out and selling it on the open market of course. >>



That's purely speculation as the Mint has taken major action against these occurrences.

WoodenJefferson

As far as I know, high speed (750 coins per min) Schuler presses have been used at Denver & Philly starting about 1995. They really came into play with the Statehood Quarter Program in 1999, cranking out the allotted quotas in the short time frame production runs.

I was maybe thinking 1995 or 1996 was a transitional period in the amount of errors found in circulation, becoming less and less as the mints modernized. I know the "Riddler" was instrumental in kicking out defective coins, but I'm at odds with a machine that requires no ejectors to sweep a struck coin away to allow the next one in.

OK...question? How is a edge on gravity fed planchet stopped over the coining chamber?

RWB

Look at:

http://www.schulergroup.com/major/pool/10_Anlagen_Verfahren/06_Muenztechnik/03_Muenzpraegepressen/02_Horizontale_Praegepresse/index.html

seanq

I don't know enough about the actual mechanics of the new presses, but misstruck coins from them all bear a similar appearance. Since 2002 or so (depending on the denomination) major off-center strikes as you know them do not exist. Most coins misstruck on the Schuler press will look like minor off-centers or more commonly uncentered broadstrikes. They are also always off in the same direction, with a very thin rim around K-7 (looking at the obverse) and a much thicker rim around K-2. Most of the time they will look 3-5% off-center, with about 10% being the max and that only on smaller denomination coins like the cent and dime. Occasionally there will be a sliver of design off the planchet at K-7. Usually you will also find scraping or abrasions in the blank area on the obverse around K-2.

I don't have a picture of a coin to illustrate this because I decided shortly after the Schuler presses came into widespread use that I would not add "off-enter" strikes from those machines to my sets. I have a date set of off-center clad dimes which I've capped at 2001 because of this. Misstruck coins are available for most dates, at least as far as my experience with the dime series is concerned, but because they are not as visually interesting as the old-style misstrikes the values have tended to be lower and collector interest spotty.


Sean Reynolds

WoodenJefferson

Thank you for the responses. It appears there is a correlation with the Mints modernizing of equipment and the amount of striking errors coming to market.

errormaven

There are quite a few double strikes and multi-strikes produced by Schuler presses (mostly state quarters) where the extra strikes are 40% - 50% off center. So it's incorrect to think that these presses cannot produce off-center strikes that are way off-center.

ricko

Interesting thread.... thanks for the information. Cheers, RickO