Everyday life at the first Philadelphia Mint was conducted to the
rhythmic thumping of the presses. Every now and then, a sickening
clang was heard. This was the sound of the dies coming together
without a planchet in place.
The resulting damage to the die or dies is called a “clashed die.”
During the manufacturing process, hardening the dies was a
difficult step that was achieved in a somewhat random manner. “The die
... was hardened by the following process,” according to Don Taxay in
U.S. Mint and Coinage. “It was first heated to a bright cherry red, a
delicate operation since excessive heat would cause even good-quality
steel to shatter. The die was then immersed in a large cistern of cold
water and swished back and forth to cool. ... The die was [then]
removed from the water. It was now, however, not only hard but very
brittle, and so it was tempered in another vessel of water which was
“When heated throughout, the die appeared almost deep blue. It was
then removed and allowed to cool slowly.”
The workers at the Mint used visual color as an indicator of the
temperature of the die steel, a nonscientific approach that was the
best they could do at the time.
This process caused each die to be tempered to a slightly
different hardness. Some were brittle and tended to crack, some were
soft and wore quickly, and some became workhorses as they were more
When two dies clashed together, the harder of the two would
impress part of its image into the field of the softer die. These
indentations in the die(s) would become the raised clash marks on the
coins we see today.
Clash marks can be found in each of the Bust series we collect.
The half dollars tend to show the defects more clearly due to their
size but some of the smaller coins can be the most spectacular.
Are you interested in seeing the date on the reverse of a Bust
coin? If so, look for an 1837 Capped Bust dime, LM-1 (Federal Half
Dimes 1792-1837 by Russell Logan and John McCloskey).
The quarter dollar series has a very famous and interesting clash
on the 1818 Browning 9 (Early Quarter Dollars of the United States
1796-1838 by A.W. Browning). You can clearly see the arrowheads
sticking out from the back of Miss Liberty’s cap.
Numerous half dollar marriages have readable parts of E PLURIBUS
UNUM visible between the date and the bust. A few also show the
arrowheads behind Liberty’s head.
I recently purchased an Overton 103 1813 Capped Bust half dollar
(Early Half Dollar Varieties: 1794-1836 by Al C. Overton
and Donald Parsley) only for the clash marks. My quest for an O-105
1817 Capped Bust half dollar with these same clash marks remains
unfulfilled — for now.
Brad Karoleff is a vice president of the John Reich Collectors
Society and editor of the club’s journal. He can be reached via email