Edge Design On Spanish Coins

Roman has it right. The Pillar coins began with the edges being applied after the strike of the coins. At some point - which varies by mint, the coiners discovered that the strike deformed the coin putting it a bit out of round. This irregularity in turn makes the edging process a bit harder and can jam the edger - also the results are not as good since the edge design goes from deep cut to weak as the diameter changes.

Edging the blank before the strike not only means you can start with a perfect circle, but you have a fixed length of circumference. That way, the edge dies could be adjusted perfectly so that the overlaps become essentially invisible. This does happen which is why on worn lotus edge coins it is often difficult if not impossible to spot the overlaps. The edging prior to the strike also upsets the edge of the blank making it an actual planchet and allowing the edge design to strike up better.

But your question is WHEN did this happen?

Unfortunately it went back and forth a couple times based on the coins I have examined in person. There is NO ONE OFFICIAL ANSWER. For example in the mid 1750s at Mexico City you can see both types and there is no absolute priority. Both edging sequences are seen in several different years. I suspect, but am open to correction that the 1750s is in general when the transformation occurred at all mints. This would be a good area for research.

The Portrait 8Rs and the Republican 8Rs are far easier. By 1770, all mints had adopted the pre-strike edging technique. So it is VERY unlikely (but not 100% impossible) that a coin is edged post strike. There is something special about Mexican coins - YOU CAN NEVER BE 100% SURE ABOUT ANYTHING. Expedience always seems to govern in practice so anything that could happen likely DID HAPPEN. What I mean is that - if for any reason the edging process fell behind the coining process - I would expect that blanks would be struck until the edgers caught up. That is why edge priority is only one piece of information I use to prove a coin is a counterfeit.

How to tell a coin is edged before or after the strike is a bit easier, but it takes practice. You need to look at both types of originals. So even though I do not personally collect the real Pillar types (I collect counterfeits), I always study them when I am at shows. To me the "HOW TO TELL?" issue is one of simple logic. If you think of the effect of striking a coin - the order of the strike causes damage to anything that was there BEFORE. So if you see evidence that the edge application damaged the obverse and reverse surfaces (usually only the outer mm or two) - you have a post strike edge. If the edge design is compressed by the strike of the two faces - you have a coin that was edged pre-strike. Any coin with well defined dentils is obviously a candidate for pre-strike edging. Weak dentils on the other hand MAY point to a post strike edging.

Restruck coins like the Brazilian 960R series and the Manilla overstrikes are both within my collecting interest range so I have some familiarity with what a later strike does to an earlier design. It can be subtile. If you have never studied a 960R - you should spend a few hours with them. Especially with regards to compression it can be very enlightening.

When an edge is applied AFTER the coin is struck, the force of that application will distort the faces of the coin slightly. This is particularly easy to pick up with the lotus edge because the design elements are SO deep and IRREGULAR with regards to the pressure applied to the coin. Look for an actual wavy effect on the surface right at the edge.

I hope this helps.