When collectors submit their error coins to a grading service for authentication, they face several possible outcomes. The coin can be accepted as authentic, rejected as fake, rejected as suspect or rejected with a “no decision” opinion.

But even when they’re given a seal of approval, some errors will still have attached to them an intrinsic sliver of doubt. Authentication is problematic for any error in which the strike is tiny, the design exceptionally weak, or the details exceedingly incomplete.

One category that invites suspicion is the profoundly weak strike, which is often mischaracterized as a “die adjustment strike,” “test piece,” “die trial” or “setup piece.” As discussed in the May 23 “Collectors’ Clearinghouse” column, such errors are more likely the result of spontaneous equipment malfunction. Apart from considerations of proximate or ultimate cause, a profoundly weak strike lacks many of the features that permit secure authentication.

Illustrating this point is an undated dime that was struck about 70 percent off-center by a malfunctioning press. The strike was phenomenally weak, possibly from a drastic drop in ram pressure but more likely from an increase in minimum die clearance. Design elements on the obverse include Franklin Roosevelt’s lower lip, chin and throat. Design elements on the reverse include the torch flame and parts of several olive leaves. The planchet is odd in having a perfectly smooth surface devoid of tumbling marks. The strike was so weak that it is almost completely restricted to the proto-rim — the highest point on the planchet. A more complete description can be found online in the Errorscope Online Supplement (Vol. 1, No. 2), located at http://hermes.csd.net/~coneca/content/ESOS070804Vol1No2.pdf.

While I have no reason to think that this is a fake, I cannot rule out a strike by counterfeit dies. So little of the design is present that it is impossible to locate any features diagnostic of a genuine die. Likewise, any toolmarks, bumps or other blemishes indicative of a fake die would not have been transferred.

Copper-nickel clad dime planchets are abundant and cheap. Any counterfeiter with a modicum of intelligence could create an undetectable fake by applying a pair of home-made dies to a genuine planchet, providing that only a light impact or a low pressure squeeze was used.

I have seen a number of highly suspicious weak strikes over the years, both in and out of slabs. Some were struck multiple times. One coin that stands out in my memory is an undated Indian Head 5-cent coin that appeared in an auction held at the January 2007 Florida United Numismatists convention. Carrying an S-Mint mark, it was housed in a slab. Design details were scant and uniformly faint. The printed description mentions “no fewer than half a dozen impressions.” The coin was pulled before the auction began.

Edge strikes are another category that can occasionally resist authentication. As the name indicates, an edge strike is a planchet or coin struck on-edge.

I’ve never been quite comfortable with the double-struck 1981 Lincoln cent depicted here. There’s no doubt that the first strike (an uncentered broadstrike) is genuine. But there’s no way to tell for sure if the subsequent edge strike is legitimate.

At the 3:00 position we find the partial motto pluribus unum. The opposite pole shows slight irregularities that presumably represent the folds of Lincoln’s coat. The letters are rather mushy and flattened, especially unum. While this could reflect a late die state, it is more likely the result of slippage against the die face or post-strike damage. All edge strikes slip against the die face; otherwise they would end up as foldover strikes.

The surface of the letters and the surrounding field seem slightly convex in cross-sectional profile. This deviation from a sharp, flat topography could again be the result of mild post-strike damage or slippage against the die face.

The mushy letters also introduce the possibility that a pair of fake dies were used to generate the edge strike. Crudely fashioned dies sometimes generate unclear details.

The last ambiguous example is a planchet with a tiny off-center, uniface strike. No die-struck design elements are present on the (presumed) obverse face. The planchet’s diameter (21 millimeters) is comparable to that of a 5-cent coin planchet as is its weight (4.95 grams). However, the highly reflective surface and a high, narrow proto-rim are quite peculiar. I can’t rule out the possibility that this is a token or medal planchet with a strike delivered by privately issued dies.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to 800-673-8311, Ext. 172.