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U.S. Mint Equipment Question
coinman23885
Posts: 1,126
As active coin collectors representing a wide range of experiences, what kinds of U.S. Mint equipment are of greatest interest to you? Also, what parts of the minting process do you find the most interesting or confusing?
The From Mine to Mint book includes information on minting processes, operations, equipment, rules and other subjects that may be of interest, and some numismatic researchers have posed this question to better respond to the interest of collectors.
Here is a link to a near identical thread ATS too: Here
The From Mine to Mint book includes information on minting processes, operations, equipment, rules and other subjects that may be of interest, and some numismatic researchers have posed this question to better respond to the interest of collectors.
Here is a link to a near identical thread ATS too: Here
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Hi Roger, we miss you!
The problem with most books about U.S. Mint procedures is they don't go into detail
enough. They write about the main workings of the Mint in general terms, such as
how dies are designed, how presses worked, the political aspects of decisions made,
etc. What is missing is the step-by-step of the following:
How the earliest dies were made by hand, cutting into steel cylinders.
What center dots, center punches and arc circles were used for, with images.
Images of the tools used, including their names & who made them.
How the earliest designs went from a drawing, to being engraved on the die face.
Describe the job titles of Mint employees and specifically what their work involved.
Produce a list of the various workers involved in die design & production and
correlate the list to the dates they were assigned at the Mint.
How die production progressed from making an incomplete matrix, to more detailed
hubs, to complete hubbing and the dates these advances took place.
How the dentils were applied.
How letter & numeral punches and logotypes were made and how they were used to
impart these features to a die.
Why were there so many design types of numerals & letters and who decided that.
Why repunching was so prevalant. Images of how corrections were made to a die.
A discussion of the force (tonnage) required to produce coinage for each of the metal
types and coin presses used over time.
How lathe lines, MPD's, DDO's, DDR's, RPM's, lint marks, clash marks, strike throughs,
fallen letters/numerals, gouge marks, die lines, spikes, broken digits/letters, guide
lines, chips, dots, lumps, sunken/bulging dies, misaligned dies, off centers, broadstruck,
overdates occured and show an example image of each.
Describe the various causes of strike throughs, what materials usually caused them
and why those materials were in the coining area.
How dies were mounted into the presses and why they became loose, causing errors.
Describe in detail how a coining press was set-up to produce coinage and what test
strikes, or trial impressions were for.
How, specifically, so many die varieties occured by replacing dies for various reasons
during the production run.
How basining of a die was done and what tools were used to do it, including images of
the die lapping process.
How proper planchet thickness was achieved using the rolling mills & draw bench and
why rolling marks occured.
And lastly, I want to know what that little cup with the long handle is next to the coin press
in the old photographs.
Good luck with your book.
Can the book be ready by next wednesday?
R.I.P. Bear
The million dollar question: How do you define a Proof Coin? Same as a Master Coin? Forget the nomenclature, is there really a line of demarcation in time in the manufacturing process of these coins that can delineate them? Evans wrote in his book that Eckfeldt reserved Master Coins being a high polish and struck with extra care. Just what is extra care? Double struck, high pressure struck, handled by hand? He supposedly was referring to the 1830's, but was the same done in the 1820's, or in the 1850's when marketing to collectors for Proof coins formalized?
How closely did the the Mint follow the law regarding the alloy of gold coins? In the 1842 Manual of Coins and Bulllion by Eckfeldt and Dubois, they stated that the law provides that the allow should consist of not more than one-half silver, but the practice of the mint is to approach the ratio of one-fourth silver. So what really happened? Are there records on the details for alloys actually used, by year, by series, by specific mint? How did they tolerate impurities? It would be interesting to try to tie this into the current look of gold coins from the different years and mints. Some coins tended to tone orange, some tended to tone "greenish", some showed their impurities.
How the heck did a transfer lathe work? An Orwellian looking machine. It took something big and made it small. How did it do that?