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Edge Strike Through

5th National Silver Dollar Convention

St. Louis, Missouri

November 8 – 11, 1984



Edge Strike Through

By Leroy Van Allen



Most coin collectors tend to ignore the third side of a con, the edge.  This is only natural since the flat sides of the cent and nickel are uninteresting as is the edge reeding of the higher denominations.  But once in a while something on the edge can grab your attention such as an edge dent, nick or scratch.

We show here a couple of unusual 1921 P Morgan silver dollars which, at first glance, appear to have edge scratches or damage of some sort.  However, upon closer examination, the edge indentions are not scratches but have the appearance of strike throughs.  These were caused by foreign material between the planchet and collar when the coins were struck.

The first 1921 P shows two indentations on the edge.  One is across the edge and parallel to the reeding.  The other is a longer, curved depression running around the coin’s edge perpendicular to the reeding.

So how do you tell if these indentations were caused by being scratched or gouged outside the mint or when the coin was struck?  If the coin was scratched after being minted, the displaced metal caused by the scratch would flow into the sides of the indentations.  This would fill in some of the reeding and push outwards to raise the rim where the indentation occurs near the outward parts of the edge.  On this 1921 P the reeding lines extend right up to the edges of the indentations with no evidence of any filling in.  Also, a scratch or gouge would produce a shiny and smooth interior of the indentation as the foreign object scraped the silver metal.  This coin shows a slightly dull and rough texture inside the indentations.

If you’ve followed the examination process with me so far, you now are probably asking yourself – okay, it is a strike through, but what was the material that caused these two strike throughs?  Two things can give good clues, the shape of the indentation and the texture of the indentation.  Obviously if the shape is thin and round then a wire was the cause.  Some strike throughs on the obverse and reverse of coins have been easily identifiable as staples, nails, and screws.  But more common things are metal fragments, grease from the press, and cloth of wiping rags.  The strike throughs of this 1921 P are rather irregular in shape so such things as wire and string can be ruled out.  The texture of the indentations shows a slight roughness with finer generally parallel lines that are raised.  This suggests metal fragments rather than pieces of cloth since there is no evidence of a thread pattern.  Likely these were silver fragments mixed in with the planchets.

A related error is laminations.  These tend to be shallow and broad with a think layer of metal separated over part of the area from the rest of the coin.  They are caused by slag and other impurities in the melt being trapped in the cast ingot and later rolled out into a thin layer of impurities within the metal strip.  Sometimes the lamination falls away from the coin or planchet leaving a ragged and rough depression that can be partly or completely covered with the impurities.  The 1921 P doesn’t have the characteristics of a lamination since the indentations are narrow and deep with no trace of impurities or rough surfaces.

Strike throughs on the edge of a coin are very rare because of the way coins are struck.  Foreign material can readily fall on top of the lower die or on top of the planchet since the die surfaces are in a horizontal plane.  The collar surrounding the dies has vertical reeding or smooth surfaces making it difficult for material to stay lodged against it.  Also, the clearance between the planchet and the collar is very small, further limiting the size of foreign material that can fit in that space.  The 1921 P shoes very small indentations on the obverse rim adjacent to the edge indentations.  So metal fragments likely were caught on the rim and edge of the planchet and carried down between the planchet and collar when the planchet fell or was forced into the collar when struck.

Another remote possibility is the pressing of metal fragments against the planchet edge when the edges were upset in the upsetting mill.  The pressures of the revolving disc and fixed circular segments could have jammed fragments into the planchet edge during the upsetting operation.  However, it is unlikely that any metal fragments would adhere to the planchet in subsequent annealing and cleaning operation prior to being struck.  Also, the upsetting operation puts pressure on the junction of the edge and rim area and not on the center of the planchet edge.  The 1921 P shows the same depth of indentation all across the edge.  So the indentation was caused when the planchet was struck and not during the upsetting operation.

Another interesting edge strike, though also on a 1921 P Morgan dollar, is shown in the second photo.  It shows a long indentation on one side of the edge.  The indentation is angled with greater depth at the edge center.  The coin rim is stuck up very high at the indentation area.  In this case the indentation surface is very smooth with a couple parallel raised and depressed lines running parallel to the length of the indentation.  Because of the sharpness and depth of the indentation, the foreign material was much harder than the planchet alloy of silver and copper.  It could have been a fragment of steel or brass shaving that somehow got mixed in with the planchets or fell into the press.

This edge indentation obviously was caused during striking of the coin since the edge reeding goes right up to the indentation without having been displaced or filled in.  There is no metal displaced beyond the flat die surfaces and collar reeding circumference which would be the case from damage to the coin after it was struck.

As with most error coins the usual question is how much is it worth?  For strike throughs it depends upon how large it is and the visual impact.  Obviously a strike through with a readily identifiable object like a staple or screw has more eye appeal and would bring a large premium of 100 to 200 percent.  Strike throughs of fragments and grease need to be fairly large (1/6 to 1/5 coin area) before they bring much over 50% premium.  The two 1921 P Morgan collars with edge strike throughs carry a 50 to 100% premium because of their rarity as well as visual impact.

The double edge 1921 P strike through came from Len Roosmalen, Len’s Coin and Stamps of Wisconsin and the other 1921 P cam from Art Leister, Commercial Coin Pennsylvania.  These alert dealers recognized the unusual nature of these silver dollars.  So don’t totally ignore the coin’s edge – they can sometimes be interesting and profitable.

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