The Science of the Strike: The Metallurgy of the Scam Bliss Coin Press

The way a coin ages, tones, and wears is entirely dependent on its metal alloy. Here is a scientific breakdown of this piece.

When I examine any coin — whether it’s a gleaming proof fresh from the press or a well-circulated Lincoln cent pulled from a roll — I’m looking at the end result of a complex metallurgical process. The alloy composition, the preparation of the planchet, the pressure applied during the strike, and the resulting metal flow lines all tell a story. And when the coin in question was struck on a rare and historically significant press like the so-called “SCAM Bliss Press,” that story becomes absolutely fascinating.

In this metallurgical analysis, I’ll walk you through everything a collector, historian, or investor needs to understand about these enigmatic presses — from the alloy science behind the coins they produced to the forensic evidence we can read in the metal itself.

What Exactly Is a SCAM Bliss Press?

The term “SCAM Bliss Coin Press” originated in a numismatic forum thread that sparked considerable debate and research among dedicated collectors and historians. The acronym “SCAM” has been attributed to the Special Coins and Metals department at the United States Mint — specifically, the Denver Mint. Some researchers have suggested the phrase might alternatively refer to “Special Coins and Medals,” given the frequency with which the word “Medals” appears in official Mint documentation. However, according to information provided directly by Roger W. Burdette, a highly respected numismatic researcher and author of A Guide Book of Peace Dollars, the correct expansion is indeed “Special Coins and Metals.”

From Roger Burdette: “WHAT IS A SCAM BLISS COIN PRESS? Special Coins and Metals department; Bliss Munitions Equipment Co. cartridge press reconfigured for striking coins. A surplus vertical one (a cupping press) was used to make the 1964-D Peace Dollars.”

This is a critical piece of the puzzle. The Bliss presses referenced here were originally manufactured by the Bliss Munitions Equipment Company as industrial cartridge cupping presses — machines designed to form the brass cups that would become bullet casings. These surplus vertical presses were then reconfigured by the Mint for the specialized task of striking coins. The “SCAM” designation on Certificates of Authenticity for retired dies indicates that the coin or die in question originated from within this special department and was struck on one of these reconfigured Bliss presses.

Only two Certificates of Authenticity in one collector’s database of nearly 300 listings bore the “SCAM” identifier, making these presses exceptionally rare in the documentary record — and making any coin connected to them a significant numismatic artifact with extraordinary collectibility.

The Bliss Press: From Munitions to Numismatics

To understand the metallurgical significance of a SCAM Bliss press, we first need to understand the machine itself and how it differs from the high-speed rotary presses that dominate modern minting operations.

Origins as Industrial Cartridge Presses

The Bliss Munitions Equipment Company was a major manufacturer of industrial presses used in ammunition production. Their cupping presses were designed to take flat sheets of brass and form them into hollow cups — the first step in manufacturing cartridge cases. These presses operated vertically, using a single-stroke action to punch and form metal in one motion.

When the U.S. Mint acquired surplus Bliss presses, they were fundamentally reconfigured for coin striking. This meant:

• Die installation: The tooling was modified to accept coin dies rather than cartridge-forming punches.
• Pressure calibration: The striking pressure had to be recalibrated for the specific alloy and diameter of the coin being produced.
• Feed mechanism: Instead of continuous strip feed (as in ammunition production), the press was adapted for individual planchet feeding — often by hand for small-batch special productions.
• Single-strike operation: Unlike the high-speed Schuler and Grabener presses that were becoming standard at the Mint by the late 1980s, the Bliss press operated as a single-stroke, single-coin-at-a-time machine.

Vertical vs. Horizontal Orientation

One of the key metallurgical differences between a Bliss press and the newer German-manufactured presses (such as Schuler models) is the orientation of the strike. The Bliss press is a vertical press — what German documentation would call “Senkrecht” (abbreviated “Sp” on some certificates). The newer Schuler presses used at the Mint were predominantly horizontal (“Waagerecht,” abbreviated “WP”).

This orientation difference has a direct impact on metal flow during the strike — which I’ll discuss in detail below.

Alloy Composition: What These Coins Are Made Of

The metallurgical story of any coin begins with its alloy. The SCAM Bliss presses are most famously associated with the production of the 1964-D Peace Dollar — a coin that was struck in 90% silver and 10% copper. This is a critically important detail for understanding the strike characteristics of coins produced on these presses.

The 90% Silver Alloy

From a metallurgical standpoint, a 90% silver alloy behaves very differently under striking pressure than the copper-nickel clad compositions used in modern circulating coinage. Here’s what makes this alloy significant:

• Silver is exceptionally ductile. It flows readily under pressure, which means it can fill even the finest die details — producing that sharp, mirror-like luster collectors prize. But it also means the metal is prone to spreading laterally if pressure is excessive.
• The 10% copper addition increases hardness. Pure silver is quite soft (approximately 2.5 on the Mohs hardness scale). The copper addition raises the overall hardness and tensile strength of the alloy, making it more suitable for a coin that needs to resist wear in circulation and maintain its eye appeal over decades.
• Work hardening during the strike. When the planchet is struck, the silver-copper alloy undergoes significant work hardening. The crystal structure of the metal is compressed and distorted, increasing the surface hardness of the finished coin by as much as 30-40% compared to the unstruck planchet.

Comparing Alloys Across Mint Productions

The SCAM Bliss presses weren’t limited to silver coinage. According to forum contributors who have handled defaced dies from the Denver Mint, the Special Coins and Metals department handled dies for multiple denominations. This means these presses would have struck coins in various alloys:

1. 90% Silver / 10% Copper: Peace Dollars, and potentially other silver denominations produced for special sets.
2. 75% Copper / 25% Nickel (clad): Dimes, quarters, and half dollars in clad composition.
3. 95% Copper / 5% Zinc: Lincoln cents (post-1982 composition; earlier cents were 95% copper / 5% tin and zinc).
4. Various bronze alloys: Used for Mint set coins and other special productions.

Each of these alloys requires different striking pressures and produces different metal flow patterns — which brings us to the next critical topic.

Planchet Preparation: The Foundation of a Quality Strike

In my experience examining coins under magnification, the quality of the planchet preparation is often the single most important factor in determining the quality of the final strike. A perfectly engraved die cannot compensate for a poorly prepared planchet. I’ve seen brilliant uncirculated coins with stunning eye appeal undermined entirely by surface imperfections that trace back to sloppy planchet prep.

The Planchet Manufacturing Process

Before a planchet ever reaches the press, it goes through a series of metallurgically significant steps:

1. Casting: The alloy is melted and cast into large ingots. The cooling rate during casting determines the grain structure of the metal — slower cooling produces larger grains, while faster cooling produces a finer, more uniform microstructure.
2. Rolling: The ingots are passed through a series of rolling mills to reduce them to the precise strip thickness required for the denomination. This rolling process elongates the grain structure in the direction of rolling, creating an anisotropic material that behaves differently depending on the direction of applied force.
3. Blanking: Round blanks are punched from the rolled strip. The orientation of the grain relative to the blank’s axis can subtly affect how the metal flows during the strike.
4. Annealing: The blanks are heated to a specific temperature (typically 600-700°C for silver alloys, 400-500°C for copper-nickel) and then slowly cooled. This relieves the internal stresses created by rolling and blanking, softening the metal so it can flow more readily during the strike.
5. Upsetting (rimming): The annealed blanks pass through an upsetting mill that raises a rim around the edge of each planchet. This rim serves two purposes: it helps center the planchet in the collar during the strike, and it creates a work-hardened edge that protects the design from wear.
6. Washing and drying: The planchets are cleaned to remove any residual oils or annealing scale that could interfere with the strike.

Planchet Quality in Special Mint Productions

For coins struck on the SCAM Bliss presses — particularly the 1964-D Peace Dollars and coins produced for Mint sets — the planchet preparation would have been subject to heightened scrutiny. These were “special” productions, not the high-volume output of the main production lines. The Mint would have selected planchets with:

• Consistent thickness (no thin spots or thick areas)
• Clean, scale-free surfaces
• Proper annealing (not over-annealed, which would leave the metal too soft and prone to excessive wear, and not under-annealed, which would require excessive striking pressure)
• Well-formed upset rims for proper centering in the press collar

Any deviation in planchet quality would be immediately visible in the finished coin as weakness in strike, doubling, or surface imperfections — the kind of flaws that can dramatically reduce numismatic value for even the rarest variety.

Strike Pressure: The Metallurgical Heart of Coining

The striking pressure is where the metallurgical magic happens — and where the SCAM Bliss press differs most dramatically from the high-speed presses that dominate modern minting.

How Much Force Does It Take?

The striking pressure required to fully form a coin depends on several factors:

• Alloy hardness: Harder alloys require more pressure. A silver-coin alloy (90% Ag) requires significantly less pressure than a pure nickel or stainless steel alloy.
• Coin diameter: Larger coins require more total force because the pressure is distributed over a larger area.
• Design relief: High-relief designs (like the Saint-Gaudens Double Eagle) require substantially more pressure than low-relief designs.
• Number of strikes: Some coins are struck multiple times to bring up full detail. Each successive strike requires less pressure as the metal progressively fills the die cavities.

For a Peace Dollar-sized coin (38.1mm diameter) in 90% silver, a single-strike operation on a Bliss press would typically require striking pressure in the range of 60-80 tons per square inch. This is substantially less than what is required for modern clad coinage of the same size, owing to the superior flow characteristics of the silver alloy.

Single-Strike vs. Multiple-Strike Operations

The Bliss press, being a single-stroke machine, would typically strike each coin once. This is in contrast to the Janvier-type reduction lathe process used for die making, or the multiple-strike proof coining process. For circulation strikes on a Bliss press, the single strike must accomplish everything:

1. Flow metal into all design elements on both obverse and reverse
2. Form a sharp, well-defined rim
3. Create crisp edge reeding (if applicable)
4. Produce a uniform, smooth field

This places enormous demands on the alloy’s ability to flow. If the metal doesn’t flow completely into every recess of the die in a single blow, the result is a weak strike — one of the most common deficiencies observed in coins struck on these older, lower-capacity presses. For collectors, understanding this limitation is essential when assessing strike quality and, ultimately, the collectibility of any Bliss-struck piece.

The Vertical Strike Advantage

There is a metallurgical advantage to the vertical orientation of the Bliss press. When the strike occurs vertically (ram moving downward), gravity assists in several ways:

• Planchet seating: The planchet naturally seats itself on the lower die (or in the collar) without the need for complex holding mechanisms.
• Ejection: After the strike, the finished coin can fall away from the die face by gravity, reducing the risk of sticking or drag marks.
• Pressure distribution: In a vertical press, the force vector is perfectly aligned with the die axis, producing a more uniform pressure distribution across the coin’s surface.

This last point is particularly important from a metallurgical perspective. In horizontal presses, there can be slight asymmetries in pressure distribution due to the gravitational deflection of the ram and die assembly. The vertical Bliss press is inherently more symmetrical in its force application — a factor that can contribute to superior eye appeal in the finished product.

Metal Flow Lines: Reading the Coin’s Internal Story

One of the most fascinating aspects of coin metallurgy is the study of metal flow lines — the patterns created within the metal as it flows under the enormous pressure of the strike. These flow lines are essentially the “fingerprint” of the coining process, and they can tell us a great deal about how, where, and under what conditions a coin was struck.

What Are Metal Flow Lines?

During the striking process, the metal of the planchet is forced to flow outward from the center of the coin toward the rim, filling the design elements in the dies as it goes. This flow creates a pattern of elongated grain boundaries and crystallographic textures within the metal. In a cross-section of a well-struck coin, these flow lines are visible under magnification as curved patterns radiating from the center of the coin toward the high points of the design.

The pattern of flow lines tells us several things:

• Strike quality: A well-struck coin will show smooth, continuous flow lines that extend from the center to the rim. A weakly struck coin will show flow lines that don’t reach the edge, leaving the rim and high points of the design poorly defined.
• Die alignment: If the obverse and reverse dies are not perfectly aligned (i.e., there is die rotation), the flow lines will be asymmetric — stronger on one side of the coin than the other.
• Pressure magnitude: Higher striking pressures produce more pronounced flow lines, as the metal is forced to move greater distances within the die cavity.
• Alloy behavior: Different alloys produce different flow line patterns. Silver alloys tend to show smoother, more gradual flow patterns, while harder alloys like nickel show more abrupt changes in flow direction.

Flow Lines in Coins Struck on Bliss Presses

Coins struck on the SCAM Bliss presses exhibit distinctive flow line characteristics that can help authenticate and attribute them:

1. Radial flow from center: Because the Bliss press applies force in a single, vertical stroke, the flow lines tend to radiate outward from the center of the coin in a relatively uniform pattern. This is in contrast to coins struck on high-speed rotary presses, where the flow pattern can be slightly distorted by the motion of the press.
2. Sharp flow line definition: The single-strike nature of the Bliss press means that all of the metal flow happens in one event. This produces sharper, more well-defined flow lines than coins that have been struck multiple times (as proofs often are).
3. Rim-to-center flow reversal at high points: At the highest points of the design (the areas that contact the die last), the flow lines can actually reverse direction, flowing back toward the center of the coin as the metal is compressed between the two die faces. This is a hallmark of a fully struck coin and is particularly visible in the high-relief areas of Peace Dollars.

Forensic Metallurgy: Using Flow Lines for Authentication

For collectors and appraisers, understanding metal flow lines is an essential authentication tool. Here’s how I use flow line analysis in my own work:

• Counterfeit detection: Cast counterfeits (as opposed to struck counterfeits) will not show metal flow lines at all, because the metal was poured into a mold rather than struck between two dies. The absence of flow lines is an immediate red flag — one I always check for when evaluating provenance and authenticity.
• Press attribution: Different presses produce subtly different flow line patterns. A coin struck on a Bliss press will have a different flow signature than one struck on a Schuler press, even if the same dies are used. This is because the rate of pressure application differs between press types.
• Die state identification: As a die deteriorates over its working life, the flow lines in the coins it produces change. Early die state coins show crisp, well-defined flow lines. Late die state coins show weaker, less distinct flow lines as the die details wear and the metal no longer flows as completely into the design.

The 1964-D Peace Dollar: A Case Study in SCAM Bliss Press Metallurgy

The most historically significant coin associated with the SCAM Bliss press is the 1964-D Peace Dollar. According to Roger Burdette’s research, the Denver Mint used a surplus vertical Bliss cupping press — reconfigured for coining — to strike these coins. The 1964-D Peace Dollars were never released into circulation; all known examples were eventually destroyed, making them one of the most famous “uncollectible” coins in American numismatics.

From a metallurgical standpoint, the 1964-D Peace Dollar is a fascinating subject — and one that keeps me up at night thinking about what might still be out there.

Alloy and Planchet Considerations

The 1964-D Peace Dollar was struck in the standard 90% silver / 10% copper alloy used for all silver dollars of the era. The planchets would have been prepared to the same specifications as regular-issue Peace Dollars:

• Diameter: 38.1 mm
• Weight: 26.73 grams (412.5 grains)
• Composition: 90% silver, 10% copper (0.77344 troy ounces of pure silver)
• Edge: Reeded (150 reeds)

The fact that these planchets were struck on a reconfigured munitions press rather than a purpose-built coining press is significant. The Bliss press, being designed for cupping operations, would have had a different pressure profile than a dedicated coining press. The ram speed, the dwell time (the amount of time the pressure is maintained at peak), and the pressure distribution across the die face would all have been different — factors that would have left their own unique metallurgical signature on every coin produced.

Strike Characteristics

Based on Burdette’s research and the limited photographic evidence available, the 1964-D Peace Dollars struck on the Bliss press would likely exhibit:

• A slightly different strike profile compared to Peace Dollars struck on standard equipment. The vertical orientation and single-stroke operation may have produced a coin with slightly different metal flow characteristics.
• Potentially sharper details in certain areas where the Bliss press’s vertical force application was most effective, and slightly weaker details in areas where the pressure distribution was less optimal.
• Distinctive flow line patterns that could potentially be used to attribute any surviving examples to the Bliss press, should any ever surface.

The Transition Era: Bliss Presses and Modern Minting Technology

The SCAM Bliss presses existed during a period of dramatic technological transition at the United States Mint. Understanding this context is essential for appreciating the metallurgical significance of these machines.

The Rise of German Press Technology

Beginning in 1987, the Mint began introducing Schuler presses — high-speed, horizontal-striking machines manufactured in Germany. These presses represented a quantum leap in coining technology:

• Speed: Schuler presses could strike coins at rates of 600-800 coins per minute, compared to perhaps 60-100 coins per minute on a Bliss press.
• Precision: The Schuler presses featured precision-engineered die alignment systems that minimized die rotation and ensured consistent strike quality.
• Pressure control: Hydraulic pressure systems allowed for more precise control of striking pressure, resulting in more uniform coins.
• Automation: Automatic planchet feeding and coin ejection eliminated the variability introduced by manual operation.

The Phasing Out of Older Equipment

As the Schuler presses came online, older equipment like the Bliss presses were gradually phased out. However, as forum contributor “CaptHenway” observed during a 2009 VIP tour of the Philadelphia Mint, at least one old vertical press — likely a Bliss — was still standing against the wall of the coining room, being used for small jobs like striking half dollars for Mint sets.

“I noticed one lonely old vertical coin press, probably a Bliss but I could not swear to that, standing against one of the outside walls of the coining room. I asked my guide what that was for, and he said that they used it for small jobs like the half dollars for the Mint sets.”

This is a crucial observation. It suggests that the Bliss presses — and by extension, the SCAM designation — remained in use at the Mint for special, small-batch productions long after they had been superseded for high-volume circulation striking. This perfectly aligns with the “Special Coins and Metals” department’s mission of producing numismatic-quality coins, proof coins, and other non-standard productions — pieces where meticulous craftsmanship mattered more than throughput.

Actionable Takeaways for Collectors and Investors

For those interested in coins potentially connected to SCAM Bliss presses, here are my key recommendations:

For Buyers

1. Examine the Certificate of Authenticity carefully. If purchasing a die or coin set that references a “SCAM” or “SB” press designation, request a copy of the original Certificate of Authenticity from the Mint. Verify that the press designation is clearly stated. Provenance documentation like this can make or break the numismatic value of a piece.
2. Study the strike characteristics. Look for the hallmarks of a vertical, single-strike operation: uniform radial flow lines, sharp detail in the fields, and potentially slightly weaker detail in the highest relief areas. The luster and patina patterns can also offer clues about the press type.
3. Check for die markers. Coins struck from the same pair of dies on a Bliss press will share the same die characteristics — polishing marks, die cracks, and other identifying features. Learning to recognize these markers is essential for authentication.
4. Understand the premium. Any coin definitively attributable to a SCAM Bliss press carries a significant historical premium. The 1964-D Peace Dollar, if any authenticated examples surface, would be among the most valuable coins in American numismatics — a true condition rarity regardless of grade.

For Sellers

1. Document everything. If you possess dies, coins, or certificates with SCAM or SB designations, create a detailed photographic and written record. This documentation is essential for establishing provenance and maximizing your item’s collectibility.
2. Consider professional grading. For any coins potentially attributable to a Bliss press, professional grading by PCGS or NGC can provide an independent assessment of authenticity, strike quality, and overall mint condition.
3. Research the press history. The more you can document about the specific press that produced your coin or die, the more valuable the item becomes. Roger Burdette’s research on the Peace Dollar press is an excellent starting point.

For Researchers

1. File FOIA requests. Several forum contributors have discussed using Freedom of Information Act requests to obtain Mint documentation. Templates are available online, and the process is straightforward. Focus your requests on specific departments (e.g., “Special Coins and Metals”) and specific time periods.
2. Build a database. The spreadsheet maintained by forum contributor Pete2226, with nearly 300 entries from Certificates of Authenticity, is an invaluable resource. Contributing to and expanding this database is one of the most productive things researchers can do.
3. Preserve oral histories. Firsthand accounts from Mint employees — like CaptHenway’s 2009 tour observations — are irreplaceable. Document these accounts and share them with the numismatic community before they’re lost forever.

Conclusion: The Enduring Significance of the SCAM Bliss Press

The SCAM Bliss press represents far more than a footnote in Mint history. It is a tangible link to a pivotal era in American numismatics — a time when the Mint was transitioning from older, manual processes to the highly automated, precision-engineered production systems we know today. From a metallurgical perspective, coins struck on these presses carry within their metal the distinctive signature of a unique manufacturing process: the single vertical stroke of a reconfigured munitions press, applied to carefully prepared planchets of silver and copper alloy.

The 1964-D Peace Dollar — the coin most famously associated with the SCAM Bliss press — remains one of the great mysteries of American numismatics. If any authenticated examples exist, they represent the convergence of Depression-era die engraving artistry, Cold War-era surplus industrial equipment, and the metallurgical science of coining. They are, in every sense, numismatic artifacts of the highest order.

For collectors, historians, and investors, the story of the SCAM Bliss press is a reminder that every coin is a physical record of the technology, materials, and human decisions that produced it. The alloy composition, the planchet preparation, the strike pressure, and the resulting metal flow lines are not abstract scientific concepts — they are the readable history of American coinage, preserved in metal for generations to come.

As research continues — through FOIA requests, database compilation, and the preservation of firsthand accounts — we may yet uncover more about these remarkable presses and the coins they produced. Until then, the SCAM Bliss press remains one of the most intriguing and underexplored chapters in the metallurgical history of the United States Mint.

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