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A suitable design is chosen. |
CANADIAN ERROR COINS - DIE VARIETIES
The Creation of Canadian Dies
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A suitable design is chosen. |
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The
design of a die usually begins as a concept or a theme.
Before the design is chosen, a suitable sketch may be obtained in several
ways. The most direct way is to
generate the sketch "in house."
This was done, for example, in the case of the 1977 Queen's Silver
Jubilee silver dollar when Royal Canadian Mint engraver Walter Ott made an ink
drawing of the throne of the senate. On
other occasions, such as the 1937 coinage, a select group of outside artists
were invited to submit designs. The
modern method is to have open competitions that any Canadian can enter.
The designs for the 1951 commemorative 5 cent piece and the 1964 silver
dollar were the results of open competitions, along with the “CANADA 125
coinage.” More recently the
“Millennium” coinage and many of the commemorative Two dollar coins, were
also the result of open competitions. To
date, this has been the method most frequently used by the Royal Canadian Mint.
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Once
a suitable sketch is obtained, |
Once a suitable sketch is obtained, the engraver models the design in modeling clay. This model is made on a large scale, usually 9 to 10 inches in diameter. The model is then cast in plaster of paris in intaglio (incused), from which a cameo (raised) is cast. During these steps, improvements and finishing touches are added, such as the lettering, improvements to finer details, and facial details. The final cast is in acrylic plastic.
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Pantograph machine reduces the design. |
This is placed on a three dimensional pantograph machine which reduces
the design and reproduces it in steel, in two cuts.
The first being a rough cut followed by a second cut, both cuts require a
day each to complete. Depending on
the size of the model and die, a brass intermediate reproduction may be
required. The final reproduction is
called the “Reduction punch” or the “Master hub”.
The end result is incused. After the denticles or beads are added and other finishing touches applied, the steel block is hardened to become a master die.
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Finishing touches being applied. |
From
the master die one or more “Working punches or Hubs” are produced in the
same manner as the master die was made. “Working
dies” are then produced in the same manner.
A single working hub can produce thousands of dies before it is retired.
Currently full design transfer between a hub and die, known as hubbing,
can be achieved in one strike with the use of a restraining collar around the
die blank while imparting its design.
Prior
to 1980 Smaller dies such as one and ton cents required at least two separate
impressions before acceptable design transfer was achieved, larger denominations
took up to five hubbings. Slight
varying misalignments between hubbings have resulted many types of “Doubled
Dies” as known to exist by hobbyists.
In
Victorian times prior to the use of a pantograph machine (1900) master dies were
produced by hand and with the use of “Hobs”- e.g.- a punch bearing the
portrait of Queen Victoria or other major devices were used in conjunction with
number and letter punches to produce the master die.
Working hubs and dies were produced by the current method.
It is also important to note that it was a common practice by the Royal
Mint in that era to “rehub” worn dies.
Sometimes worn dies were used to produce smaller size denominations.
Occasionally a master die has been totally hand engraved as was done in
1949 with the one dollar commemorative by Royal Canadian Mints, at that time
chief engraver, Thomas Shingles.
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Dies being prepared for plating. |
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Press used to produce working Dies, about 1910. |
Prior
to 1908 Canadian coins were struck with both major die axis arrangements.
In the medal arrangement (designated áá)
a coin held vertically between one's fingers with its obverse design right side
up finishes with its reverse design right up when it is rotated on its vertical
axis. Dies in coinage arrangement (áâ)
will result in the reverse being upside down when the coin is turned as
previously described. All Canadian coins struck by the Royal Canadian Mint (1908)
have been in the medal arrangement (áá).
The
collar (the piece of metal that restrains the sideways expansion of the blank
during striking, thus forcing metal to flow into all incused design elements,
and gives the coin its shape and edge design) is made at the Ottawa mint.
For plain edge coins a hole is simply drilled in the centre of an
appropriate piece of steel. If the
collar is to be for a reeded edge coin, a smooth edge hole is drilled.
Then the hole is given a serrated edge by the use of a small, hardened
steel wheel.
MASTER
HUB -design is raised
is struck to create a
MASTER
DIE - design is incused
is struck to create a
HUB
- design is raised
is struck to create a
DIE
- design is incused
is struck to create a
COIN - design is raised.
| Major Die Variety | Minor Die Variety |
|---|---|
| Die alterations made either intentionally or unintentionally prior to use. |
Die alterations due to die use and wear. Most are progressive in nature. |
| Punch Spacing | Die Chip |
| Different Punch Style | Die Crack |
| Repunched | Retained Broken Die |
| Over Punched | Broken Die (Cuds) |
| Added Punch | Collar Crack |
| Damaged Hub | Pitted Die |
| Modified Design | Peeled Chrome Plating |
| Mismatched Die (Mules) | Die Deterioration Doubling |
| Misaligned Die | Resurfaced Die |
| Rotated Die | Die Clash |
| Doubled Die | Tool Damage |
| Collar Type | Die Shift |
| The use of the terms of major and minor by these definitions apply only to Canadian die varieties. | |
The
Evolution of Minor Die Varieties
Eventually,
after a period of use, coinage dies do breakdown, in some cases earlier than
others. Poor Quality steel from which dies are formed, was clearly a
problem in die production (particularly during the Victorian era).
The breaking down of a die may at first reveal;
“Die
Chips” small chipped of portions of the die, usually where the field meets an
element. Also weaknesses in the
design of the die, in regards to metal flow, account for many chipped dies such
as plugged dates and letters.
“Die
Cracks” that are progressive in nature will occur.
Coins struck by cracked dies will mirror the crack showing as a raised
line on the coin, usually in the fields extending from design elements.
“Die
Breaks” Are the result dies continuing to strike coins, the die crack tends to
grow longer and deeper into the die, eventually this will result in a piece of
the die breaking off. Coins struck
by dies with broken off edges are known as “Die Breaks” (more popularly
known as in the USA as “Cuds”).
“Pitted
Dies” Dies formed by poor steel may result in porosity being exposed in the
field after polishing, these pits may appear as dots when impressed to form a
coin. Tool damage and other types
die mishandling may also result in producing 'dots.'
“Chipped
or Peeled Plating” occurred quite commonly.
Beginning in 1941 the mint began chrome plating the dies to prolong die
life. In the early years (1941-1965) of plating dies many problems
arouse, due to difficulties in the adhering of the plating.
“Die Deterioration Doubling” usually appears late in die life (unless it was helped
by polishing) and is caused by fatigue around recessed design elements on the
die. This doubling usually extends
on all sides of the raised element, often accompanied by fields exhibiting
'orange peel effect' typical of worn dies.
Often both of the die pair are affected.
Polishing dies to remove clash marks (e.g.) can also produce this effect
and may appear on fresh looking dies.
“Over-Surfaced Die” during some years, used dies and damage (e.g. clash marks) were totally resurfaced and replated. Fine details are sometimes removed and elements may appear smaller.
"Die Clash" marks on coins are the result of working dies striking each
other when no planchet is between them. Bent planchets when fed into a hopper-
feeder will jam, preventing planchets from being placed in coining chamber.
The face of most modern dies is slightly convex. On these issues, die
clashes are deepest at their highest points, nearest to the centre of the coin.
On dies that are concave, clash marks
will be found nearer to the edge of the coin. Due to modifications of the presses in 1980, that enable presses to
disengage dies if no planchet is fed, these varieties are seldom seen anymore.
"Die Shift" may be caused by a loose die, this is actually damage that occurs
after the strike and damage that occurs after the strike may be duplicated.
The doubling is the result of displacement (shearing) of the raised
element, this pushing over the metal not only narrows the elements, but also
pushes this metal up on the edge of each character. When the base of the doubling is added to raised part, it is
equal to the full normal size of the raised element. On regular coinage, meant
for circulation, this is rather common and does not justify a premium value as a
minting variety.
Currently
eight classes of hub doubling are recognized.
Class
I-"Rotated Hub Doubling"-results from a rotation (in either direction)
of the second impression in relation to the first.
Class
II - “Distorted Hub Doubling”-occurs when the hub has spread out or
distorted between impressions, and may involve the use of two different hubs.
Class
III - “Design Hub Doubling” -always involves two different hubs, one with a
different design, or the design in a different location.
Class
IV - “Offset Hub Doubling” -occurs when the second impression is offset in
any direction.
Class
V - “Pivoted Hub Doubling” -occurs when the second impression is pivoted at
some point, usually the rim, so that the doubling increases in a fan shape from
the pivot point.
Class
VI - “Distended Hub Doubling” -often will not show he distinct notching that
all other forms of hub doubling, as it results in a thickening of elements and
design.
Class
VII - “Modified Hub Doubling” -results from the use of a modified hub.
Class
VIII - “Partial Hub Doubling”-occurs when a die is partially hubbed, usually
offset, and is rehubbed.
There
are also - T. D. -Tripled Dies and Q. D. - Quadrupled Dies.
O
- denotes obverse die, R - reverse die.
Doubled
Die are listed in this order:
Denotes
which Die the class-
for
example - $1.00 1947 Pointed Seven 1-R-V & T.D.0-II
1
means it is the first recorded for that date
Dies in
the coinage alignment (áâ)
Newfoundland
-1872
(only) One cent.
-Five
cents.
-Ten
cents.
-Twenty
cents.
-Fifty
cents.
New
Brunswick
-Five
cents.
Province
of Canada
-Five
cents.
-Ten
cents.
-Twenty
cents.
Canada
-Five Cents 1870-1907.
-Ten Cents 1870-1907.
-Twenty-Five Cents 1870-1907.
-Fifty Cents 1870-1907.
Dies in
the medal alignment (áá)
New
Brunswick and Nova Scotia Half Cent and One Cent.
Prince
Edward Island One Cent.
Newfoundland
One Cent except 1872.
Province
of Canada One Cent.
All
Canadian One cent, and beginning 1908 (Since the Royal Canadian Mint began to
strike coins) all coinage.
Since 1858, all coinage for Canada has been struck from dies of different curvatures. Dies may also vary in slight degrees in their curvature. It can vary yearly or within the denominations depending on the design.
Page created by: muckwa
Changes last made on: 02/14/10
