1749 Pillar Copy

Nice copy but rather modern. (In my opinion, made sometime after the 1970's but it could have been made last year just as easily.) I did not encounter fine grained cast molds prior to the early 1970's and I suspect the advent of high strength plastics as the reason. Plastic like the type that are used for dentle fillings can approach the strength of steel and can be suitable to make dies as well as molds. But the cast versions CAN predate the strikes because fine grained cheap plastics could be used to copy an image perfectly. I worked in the plasyics inductry for a summer while in college (1965) and got a good feeling for the capability of plastic to copy mold details precisely.

The surfaces visible clearly in the close-ups appear typically cast in nature. The shot of the assayer initials and the legend "DND VI" shows this well. There are tightly spaced minute bumps on the surface (no really visible - but the effect is visible). These minute bumps will make the surface diffuse light randomly giving the coin a dull finish. A real strike creates the pin wheel effect by ligning up the surface texture radially in the direction of metal flow. In worn dies the surfaces actually erode radially. The reflection (mint luster) is a solid clue to differentiate a strike from a casting.

In the same picture, you can also see the "rounding" of the letters typical of casts. The image is NOT SHARP. The D is severely distorted at the corner and the likely cause is a small piece of the mold tearing away at some point in the process. This kind of problem can be progressive so that casts can be placed in age order according to mold deterioration. This is similar to die aging BUT MUCH FASTER on molds.

The feature visible on the N's is an original feature which copied poorly. Something similar (casued by the same factors) can be seen on the E. The letter punches used to make these dies had fairly shallow details even when they were new. The punches had careers that lasted years in some cases so refininshing the punch by grinding the face flat was inevitable. Every time the punch was re-cut in this way the image became more shallow. It took less pressure to drive the punch FULL DEPTH into the die. In this case, the N was not fully formed as you go deeper into the punch (think cross section). The N widens the further you go from the face of the punch. So when the punch is set into the die - the transition from well defined N to the rectangular punch body shows more and more. The base of the N is wider and is re-inforced by the added metal. Since the individual punches were cast from a master mold made in Spain it is apparent that the mold had a very shallow letter N. A punch with a long well defined N would have broken easily. It would also wear quickly in use - so the shallow N with visible shoulders were normal. In this case, the "metal shoulders" show particularly well because the N punch used on the original many have been re-surfaced a couple times before it was used to make the die for the original host coin.

This coin was cast before being edged which is shown by the distortion of the coin near the edge. The undulating pattern near the edge is caused by the compressive effect of the edging mill. This post creation edging makes the coin look thicker than a coin struck on a pre-edged blank. The edge being applied AFTER the coin was cast allows the forger to use a simple middle of the coin seam. The seam is ground off and then the coin is edged in an edging mill. The traces of the grinding are also removed by the application of the edge.

The second reason for a slightly thicker coin is to get the weight nearly correct. The coin has an SG of 10.02 which equates to nearly 70% silver but that means the coin will be 20% too light if it is exactly the volume of an original - so it makes sense that the coin should be slightly thicker than a real one. It is easier to get away with thickening the coin than it is to increase the diameter.

odentheviking You are right about a tumble polisher possibly being used. They work fine to produce a nice even wear with no big hits or distracting scratches. Using a tumble polisher can also knock the corners off details like lettering - the result can be the rounded appearance of the letters here.