Newcomers to the hobby often ask if their clips, or incomplete planchet coins, are genuine. Determining authenticity is a snap once you know the four key diagnostics.
Blakesley Effect: At the pole opposite a clip you’ll often find the design rim to be weak or absent and the edge to be unusually wide. Designated the Blakesley Effect (after its discoverer), it can be seen on the illustrated 1965 Washington quarter dollar opposite each of the two small curved clips located respectively at 12:30 and 3:00.
During upsetting — when a blank is rolled and squeezed into a planchet — the latter’s proto-rim can only form when there’s resistance at the opposite pole. Any interruption in the blank’s circular outline will briefly eliminate that resistance, preventing formation of the proto-rim. The planchet also bulges out in this area, creating a tight fit with the collar. As a consequence, the design rim fails to strike up properly while the edge is especially well-struck.
The Blakesley Effect is often absent in the case of large clips. That’s because the dies’ impact is concentrated on a much smaller piece of metal, boosting the effecting striking pressure. This increased striking pressure overcomes the lack of a proto-rim and generates a normal design rim.
Metal Flow: Design elements bordering a clip often show metal flow. In our 1965 Washington quarter dollar, the letters ER DOLL are stretched out and distorted. Metal flow results from coin metal squeezing out from beneath the die as it follows the path of least resistance.
Fadeout and taper of the design rim: As the design rim approaches a clip it will taper and fade out. Metal that should ordinarily rise to fill the rim gutter instead flows toward the gap in the planchet. The reverse face of a 1972 Lincoln cent shows the effect at both ends of a small curved clip.
Reversal of cut-and-tear edge texture: The previous three diagnostics are useful for any kind of clip (curved, elliptical, straight, or ragged). In fact, they can be used to authenticate any type of interruption in the circular outline of a coin, provided that interruption occurred before the strike.
Our last diagnostic is, however, only useful for curved (concave) clips and is best seen on clad coins where one takes advantage of a proxy phenomenon — a reversal in the asymmetrical exposure of the copper core.
When a blanking die (punch) pushes through the coin metal strip, the sharp edge of a hole in a perforated base plate slices through the bottom half of the protruding blank, producing a relatively smooth texture on the lower half of the blank’s edge. As it’s pushed even deeper into the base plate hole, the blank eventually tears free, leaving behind a rough, grainy texture along the upper half of the blank’s edge.
The process is reversed for the hole that’s left in the coin metal strip. The sharp edge of the blanking die slices through the upper part of the strip, leaving a smooth texture along the upper half of the hole’s edge. When the blank tears free of the strip, it leaves behind a rough texture along the lower half of the hole’s edge. A blank with a curved clip has part of a hole along its edge, where the edge texture is inverted relative to the convex portion of the blank.