Split Planchet (SPL)
A split planchet error occurs when a coin's metal blank cleaves into two separate pieces along a plane parallel to its faces. Unlike a lamination, where a surface layer peels or flakes away, a split planchet is a complete separation -- the planchet comes apart across its full width, producing two thinner pieces. Mike Diamond notes in Coin World that the two pieces can be close to equal in weight or very unequal, depending on how far beneath the surface the split runs. Each piece weighs less than the standard specification for the denomination.
Split planchets and laminations are similar in appearance and cause. Both are believed to come from contaminants in the alloy or from a poorly mixed alloy, which leave a plane of weakness inside the metal. The planchet can split before it is struck, or the coin can split afterwards.
How Does It Happen?
Split planchets originate from the same metallurgical defects that cause lamination errors, but the flaw is more severe -- running across the whole planchet rather than lifting a patch near the surface.
The common causes include:
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Contaminants in the alloy: Foreign material in the metal, such as trapped gas, dirt or non-metallic inclusions, does not bond with the surrounding metal and creates a weak internal plane.
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Poorly mixed alloy: An alloy whose components are not evenly mixed can also produce a plane along which the metal separates.
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Solid alloys, not clad: Error-Ref and Diamond both describe split planchets as almost entirely restricted to solid-alloy coins, such as copper-alloy cents and copper-nickel five-cent pieces; Error-Ref names cents and nickels as the U.S. denominations most often affected. Clad coins that come apart between their layers are classed separately as separation errors, which are bonding errors rather than alloy errors.
Before Strike vs. After Strike
Split planchets are classified by when the separation occurs relative to the striking process. The distinction significantly affects the coin's appearance. Diamond writes that planchets are much more likely to split before the strike than after.
Split Before Strike
A planchet that has already separated before entering the coining press. A piece that reaches the dies is struck on its own, split face and all.
Characteristics:
- Both faces are struck, but usually weakly, because the thinner-than-normal planchet does not fill the dies
- The split face (the interior surface exposed by the separation) shows a pattern of striations, from fine to coarse; Error-Ref notes that an unusually strong strike can efface most of them, while a weaker one leaves them with little design
- Weight is below normal; how far below depends on where the planchet split. Error-Ref's examples include a 1961-D cent and Indian coins at 1.0 g (of 2.25 g) and 3.2 g (of 6.0 g)
Split After Strike
A coin that splits after it was struck as a complete planchet.
Characteristics:
- The face opposite the split usually shows full detail, struck at normal depth because the planchet was intact during striking
- The split face shows striated, rough internal metal
- Some after-strike splits show faint ghost images of the design through the striations; Error-Ref illustrates a 1959 cent whose split-off reverse layer, weighing 1.4 g, shows only a muted, striated ghost of the Memorial and Lincoln's profile
- Each piece is below normal weight, and the two pieces together should approximately equal the weight of a normal coin for that denomination
- After-strike splits produce the possibility of reuniting both pieces from the same coin
How to Tell the Difference
| Feature | Split Before Strike | Split After Strike |
|---|---|---|
| Design on the unsplit face | Usually weak | Full strength, normal depth |
| Design on split face | Struck over striations, usually weak | Striated, may show ghost impressions |
| What survives | A struck piece, both faces die-struck | Two pieces, each with one die-struck face |
| Weight | Below normal | Each piece below normal; together about normal |
Diamond adds that a split-before-strike planchet struck in the collar beneath a normal planchet can be mistaken for an after-strike split, because its striations survive with only slight softening.
How to Identify a Split Planchet
Split planchets have distinctive characteristics:
- Below-standard weight: A split planchet coin will always weigh less than a normal coin. This is the most reliable first diagnostic.
- Striation pattern: The split face shows a characteristic pattern of fine to coarse striations -- the exposed interior structure of the metal. This texture is distinctly different from a struck surface.
- Thinner than normal: The coin is noticeably thinner than a normal example of the same denomination, because part of its metal is on the separated piece.
- Not rolled thin, not cracked: Diamond notes that coins on rolled-thin stock lack the striations, and that "split planchet" is often misapplied to cracked planchets, whose cracks run through the coin from face to face rather than parallel to them.
Split Planchet vs. Lamination
| Feature | Split Planchet | Lamination |
|---|---|---|
| Extent of separation | Complete -- coin cleaves into two pieces | Partial -- surface layer peels or flakes |
| Depth of flaw | Anywhere in the thickness | Typically near the surface |
| Remaining coin | Each piece is separate | The coin remains intact with a missing or peeling surface layer |
| Design visibility | Each piece keeps at most one die-struck face | Design remains visible on the intact coin |
Notable Examples
Jefferson Nickels
Copper-nickel five-cent pieces are one of the solid alloys in which splits occur. Error-Ref shows a 1945 Jefferson nickel whose reverse split away after striking, leaving a 3.1-gram obverse piece.
Both Pieces Together
The most complete split planchet specimens are both pieces of the same coin, reunited. In an after-strike split, one piece carries the obverse design and the other carries the reverse. Diamond describes both halves of a 1944 Lincoln cent: the direction and texture of the striations match on the two pieces, and their combined weight equals a normal cent's 3.1 grams, which together show that the pair is genuine. Diamond calls such a reunited pair a mated pair; the hobby also uses "mated pair" for two separate coins struck together in the same press cycle, so check which sense a listing means.
Diamond also describes partial splits, called clamshell splits, where the cleavage runs only partway in from the edge and leaves a cleft.
Lincoln Cents
Split planchets on Lincoln cents are among the most accessible examples for collectors. Bronze and brass cents (through 1982) are solid alloys and split in the classic way. Copper-plated zinc cents (1982 to date) that come apart at the plating are, in Error-Ref's terms, separation errors rather than split planchets.
Collecting Tips
- Weigh the coin: Weight is the most reliable diagnostic. If you suspect a split planchet, weigh the coin on a precision scale. It should be below the denomination's normal weight.
- Before or after: Decide whether the split happened before or after the strike, using the strength of the design on the unsplit face and whether the split face was struck.
- Matching pieces: If you acquire one piece of an after-strike split, the other piece exists somewhere. Matching striations and a combined normal weight are the tests for a reunited pair.
- Protect the split face: The striated interior surface is more vulnerable to damage than the struck surface. Use appropriate holders and handle with care.
- Authentication: The combination of below-normal weight and the characteristic striation pattern is what an authenticator looks for.
- Solid-alloy coins: If you're hunting for split planchets, solid-alloy coins such as bronze cents and copper-nickel or wartime silver nickels are where they occur; clad coins are generally not susceptible.