The Screw Press

Cladiator

I saw this picture in a coin auction that's on eBay right now. It's one of the only pictures/drawings of the screw press that I've ever seen and just wanted to share.

Cladiator

Here's a photograph of a very similar machine...

TomB

I don't know if the Smithsonian still has it on display, but several years ago there was a screwpress in the middle of the numismatic exhibit.

DUIGUY

Ram speed would be so slow the guy feeding it would not be in danger of loosing any fingers , maybe a head if he fell asleep and nobody noticed . Thats what you call "screwed to death" .

Barndog

Recommended reading (required reading, I think) is Denis Cooper's "The Art and Craft of Coinmaking: A History of Minting Technology" if one wishes to learn more in-depth about making coins. The book is perhaps the most comprehensive look at minting technology written. The 1988 book, published by Spink and Son, will set you back a few hundred dollars...IF YOU CAN FIND A COPY!

Barndog

just saw the auction that included the picture of the screw press, very nice LM-14

nwcs

Anyone know off the top of their heads how many coins can be produced in a day on one of those? I'm wondering if, other than in quality, it actually could produce more than the hammer/mill presses.

slumlord98

Neither of those looks much like the 80 ton press used by Gallery Mint Museum, which was sold for scrap by the mint in the 19th century. Also, the US Mint's machine had an automatic feeder, the malfunction of which is responsible for the badly clashed half dollars of 1813 and 1814. Check the ANA website, money.org, to see if they will be there this year. If they are, it is an opportunity to learn like no other.

I also would join in recommending the Cooper book. It is surprising to hear what it sells for today. I was lucky enough to buy two new copies 5 or 6 years ago for $125 each. Wish I had held the second.

Barndog

<< <i>Anyone know off the top of their heads how many coins can be produced in a day on one of those? I'm wondering if, other than in quality, it actually could produce more than the hammer/mill presses. >>



See MrHalfDime's very informative post on this topic in this Dec 2005 thread:

Words of Wisdom

WWW

Ah, the good old days... Here is a bigger image of the drawing:

Cladiator

Looks like 1$ planchets

slumlord98

I would disagree with a couple points in MrHalfDime's post. Craig Sholley's research suggests that the dies were left in the press each night and something was placed between the dies to prevent clashing, and then the hammer was lowered to just above contact with the anvil, and chained into position to prevent misuse. Also, production was more on the line of 45 coins/minute. This is according to an excerpt from the journal of a visitor to the mint in 1828, which was reprinted in The Coin Collector, the weekly paper of B+M, back in the olden days when there was a Bowers and a Merena there. I quote-

"Tuesday, Oct. 14, 1828
I and Mr. Fisk left the company at the gate and went to see the US Mint. There they were, striking off half dollars in one room, and cents in another. The other part of the works were not in operation. I enquired how many half dollars they struck off in a minute and they said 43. The pieces of silver were plated out and cut to the right size previously, so that they were only given the impression. It took three men to do this; all of them had hold of the machine at a time and it appeared to be pretty hard labor."

If dies were removed each night, and replaced randomly with any obverse and any reverse from the bin, there would be an endless assortment of marriages and remarriages. Rarely, this may have happened and may account for one or two of the very few half dollar remarriages extant. Also, there are references to chains attached to the swing bars which brought the hammer to a dead stop and a springboard attached to the ceiling acted as a return spring. These simple devices absorbed the excess inertia and forward momentum of the press.

Also, by the late 1820s, there was quite a lot of bullion at the mint and when a customer brought in bullion for coining, they seldom got their own exact bullion back in coinage. The mint was producing millions of halves per year by this time, and the mint had become more of an assembly line than a boutique. The government began buying bullion as backing for the second national bank by 1818 and this was all coined, and provided some "stock" bullion at the time. A permanent bullion fund wasn't authorized by Congress til 1837.

Coinosaurus

<< <i>Ram speed would be so slow the guy feeding it would not be in danger of loosing any fingers , maybe a head if he fell asleep and nobody noticed . Thats what you call "screwed to death" . >>



I read, somewhere, that most of the coiners in the London mint had parts of fingers missing. In the US, there was some sort of mechanical ejector device (introduced pretty early on) that pretty much solved the problem. I think I got that tidbit from Taxay or Sholley.

As for your attempt at humor, I might add that "The Screw Press" would be an interesting name for a numismatic periodical