The Creation of Canadian Dies
By Patrick Glassford | Sunday, 14 February 2010
The following content comes from Patrick Glassford website which no longer exist. To keep this information available to the public and for a perpetuity reason, we reproduced it here.
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.
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.
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. From the master hub at least two Matrix or Master dies are made by placing it in a powerful press and impressing its design into soft steel blocks, which are later hardened. For small mintage coinage such as a one year or monthly commemorative, the need for a master hub is bypassed by using a reversed image (incused) model on the pantograph machine.
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.
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.
Prior to 1908 Canadian coins were struck with both major die axis arrangements. In the medal arrangement (designated ↑↑) 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 (↑↓) 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 (↑↑).
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.
Major Die Variety
Die alterations made either intentionally or unintentionally prior to use.
- Punch Spacing: Variations in numeral spacing and alignment, may be vertical, but mostly horizontal. Usually involves the last digit of date, and only involves dates and mint marks.
- Different Punch Style: These are the result of two different punch styles used to complete dies in a particular year. Involves only the date and mint mark. Many types of single letter or number punches were available to engravers. Variations in style and size varied depending on the denomination and the country involved.
- Repunched: Imparting the design of a number punch or mint mark into a die with a mallet, often requires more than one blow. Slight misalignments (either lateral or pivotal) or the angle at which the punch was held, will sometimes appear as doubling on struck coins. Involves only the date and mint mark.
- Over Punched: Can occur two ways: When the date is ground down to create a blank dated hub, not quite all the previous date has been removed, and when punched with a different number punch traces of the original date are still some what visible. Can also occur by applying a numeral or letter punch directly to a die over an existing punch mark.
- Added Punch: Dot or Maple leaf used to mark dies used in the subsequent years due to necessity. (No modified master dies ready)
- Damaged Hub: Dies produced by chipped or broken hubs lack those affected portions of elements, usually letters. Very rarely elements may be "Sheared and displaced", please refer to the images of the 1999 February issue below.
- Modified Design: Any difference in design elements or depth of relief that occur within a particular year. Design modifications are usually done to facilitate metal flow, thereby relieving stress to edges of design elements on dies during striking.
- Mismatched Die (Mules): Commonly known as "Mules" and are the result of dies that were not intended to be paired.
- Misaligned Die: When the top die is laterally off-set in relation to the collar and bottom die.
- Rotated Die: Since 1908, all Canadian coins have been struck in the medal arrangement. Coins showing different die axis arrangements are the result of a die in a wrong position in relation to its mate.
- Doubled Die: Prior to 1980, impression of a die required up to five hubbings to achieve total transfer of the design. Slight misalignments (may be lateral, rotated or pivotal for example) between hub and die may occur. Also includes dies that have been hubbed by two distinctly different hubs. In the past the terms "Re-engraving", "Re-cut", "Re-entry" and "Re-entered" were intended to describe Doubled Dies. Shifted, Rotated, Swing and Rocking was also used to describe the "Shift". These terms were incorrectly applied most of the time, most coins described this way are actually Die Deterioration Doubling.
- Collar Type: When two different collar types are used in the same year.
Minor Die Variety
Die alterations due to die use and wear. Most are progressive in nature.
- Die Chip: These are small chipped off portions of the die, usually where the field meets an element. May appear as raised "blobs" or "fillings" adjoining design elements of a coin. 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 Crack: Coins struck by cracked dies have this crack showing as a raised line, usually in the field.
- Retained Broken Die: Most Die Cracks tend to grow as the dies continue to strike. Portions of the Die may come apart and retained for a few strikes before falling away. These will always exhibit a difference in the depth of its field in the affected areas.
- Broken Die (Cuds): Die Cracks tend to grow longer and deeper into the die, eventually this may result in a piece of the die breaking off. Coins struck by dies with broken off edges are also known as "Die Breaks". -More popularly known as in the USA as "Cuds".
- Collar Crack: Collars that crack will cause a raised line to form on the rim of a coin. Rarely seen, however these must be included for completeness.
- Pitted Die: Dies formed by poor steel may result in porosity been exposed in the fields during polishing. Pits may also form in the chrome plating of the die. These pits may appear as dots when impressed to form a coin.
- Peeled Chrome Plating: Beginning in 1941 the mint began chrome plating the dies in an effort prolong die life. In the early years (1941-1965) of plating dies many problems arouse, due to difficulties in adhering of plating. Often called "Mortar set" in the sixties.
- Die Deterioration Doubling: Usually appears late in die life and is caused by fatigue around the base of recessed design elements on the die. These areas receive a large amount of friction as the metal flows during the strike. The carbon in the dies steel dissipates and results in the collapse of those areas over a period of time, depending on the quality of the steel used to form the dies. This doubling usually extends all sides of the raised element both sides and all over the die, often both of the die pair are affected. Sometimes accompanied by fields exhibiting "orange peel effect" dies typical of worn dies. Dies that clash are routinely polished to remove the damage and make the die usable. Often the polishing will leave a "shelf" around design elements on the die. When these Dies strike coins, they may appear to have elements with extensions and doubling. Concave dies, convex dies and flat dies all take polishing a little differently from each other. The fields of a convex die are not flat - they are curved outward. When these dies are polished it tends to flatten the fields. The base of design elements, numbers and letters in these areas will sometimes appear as doubling and/or added and/or extended design elements on the struck coin. A coin described as Die Deterioration Doubling may include Polish Doubling as they can be very similar in appearance and sometimes impossible to distinguish how the effect occurred.
- Resurfaced Die: Occasionally, used and damaged dies were totally resurfaced and replated. Fine details are sometimes removed and elements may appear smaller.
- Die Clash: A coin that has Clashed Die "marks" shows the result of damage that occurs when the obverse and reverse dies slam together with no planchet in the collar. Bent planchets when fed into a hopper-feeder will jam, preventing planchets from being placed in coining chamber. The most vulnerable areas to clash marks are the highest areas on the face of the die, and these are the fields- the area that is lowest on the struck coin. The "mark" occurs where the design elements of the opposite die contact fields on the affected die, leaving its impression. Canadian dies are slightly convex and clash marks from an opposing dies design will always appear strongest in the fields closest to the center of the affected dies. The opposite is true on dies that are slightly concave, such as some issues of Canadian coins (prior to 1937) and currently by many foreign mints around the world. On these types the clash marks will always appear strongest in the fields closest to the edge of the die. On dies that are totally flat, neither concave nor convex, the clash marks appear uniform across the fields. Since new modifications to presses (1980), that enable presses to disengage dies if no planchet is fed, these varieties are seldom seen anymore.
- Tool Damage: In very rare circumstances, a Die can be damaged by the Feed Finger that is of an equal or greater hardness than the Dies. Evidence of this damage will usually appear on both the Obverse and Reverse Dies. Prior to 1990(?) coins were fed from the 12 o'clock position, with the Feed Fingers traveling vertically in relation to the portrait of the Queen on the Obverse Die. Some time in the early 90's the direction that the Feed Fingers travel was changed. They now come in from the 9 0'clock position and travel horizontal in relation to the portrait of the Queen on the Obverse Die. When a Die pair "Strike" a portion of the Feed Finger, they usually become dented. When they strike coins it appears as a warp in the fields, reminiscent of Occluded gas types of Planchet Varieties, but are totally unrelated as to cause. Dies damaged this way tend to deteriorate very rapidly and are quickly replaced. "Tool Damaged Doubling" refers to a very rare occurrence where Dies have struck previously struck Feed Fingers. Dies may pick up impressions from the Feed Finger and then impart this "Doubling" of the design elements onto coins.
- Die Shift: Die Shift is caused by a loose die. This is actually damage that occurs after the strike. The doubling is the result of displacement (shearing) of the raised element. This pushing over of 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 the raised part, it is equal to the full normal size of the raised element. Also known as "Ejection Doubling", "Machine Doubling" and "Die Chatter".
The use of the terms of major and minor by these definitions apply only to Canadian die varieties.
- Canadian coins
- Canadian banknotes
- Canadian tokens and medals
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