Edges Of Milled Pillar Dollars

Old age everyone - I forgot to clarify what I was trying to say in regards to my comment- "If there was some temporary problem with one of the cutting dies could it be that production was kept going with just one die while the other was resurfaced?"

This would then mean that the coin would do a full 360 degree rotation and there would be just the1 join or stop start point on the coin's edge.

The edge design should show 2 overlaps. Simple physics dictates that if you are rolling a coin along two parallel dies, there should be two points at 180 degrees from each other that show the point at which the imprint from the one die made its way around the coin to overlap the imprint from the other die. That said, there are always variations. I have seen coins that were authentic in every way I can diagnose yet I could not find a single overlap. Possible that the images lined up perfectly? The examples I have seen were all dated between 1762 and 1768,a period of time when the planchet size seems very consistent and the production standards were very high. (I am always suspicious of a coin from that period that does not look very sharply and cleanly struck.)
As for the image running in 2 directions, that occurs on 8 reales from Mexico and Guatemala up to 1763. The edge showing different direction on an 8 reales from a different mint or outside those years would be a very suspicious coin.
I have never seen a legitimate coin with only one overlap, most of those coins also show other signs that raise suspicion of a counterfeit, though possibly a contemporary one or the type Swamperbob refers to as bullion counterfeits minted to full silver weight to satisfy the insatiable demand in China for pillar and Portrait Spanish colonial dollars.
Please post pictures of your coin, including photos all around the edge and with close up of the different feature on the obverse and reverse. I would love to be enlightened to a single overlap coin that is certifiable as legit. (Though that said I put no faith in the TPGS)

collectacoin, I am afraid your coin is fake.

You can see more about your coin by this post:

https://goccf.com/t/133160&whichpage=2

Thanks for every one's replies.

The thing is then if it is a fake it must be comprised of genuine silver if the diameter and thickness and specific gravity is within the correct tolerances or is there another explanation?

collectacoin, I don't think your coin is made of genuine silver, you had better to check the S.G. of it. I have 4 pillar coins: 1739, 1753, 1763 and 1771, all Mexican, have S.G. ranges from 10.214-10.318, corresponding to 84.13%-90.86% silver. They are all genuine in my opinion. S.G. is useful to pick out those debased counterfeit silver coins but S.G. can never answer how much silver content inside a coin accurately because every object has its weight and its S.G., this does not mean they have any corresponding silver inside.

So your assertion : "The thing is then if it is a fake it must be comprised of genuine silver if the diameter and thickness and specific gravity is within the correct tolerances" is not correct. Henry

Just a few random late thoughts.

Most critically is that the manual edging mill did NOT have long edge dies like the later powered machines machines capable of edging multiple coins.

The short dies were more economical to make. Wasting a lot of steel would never have been done. Die steel was expensive and a double long bar is twice the work for the die maker.

The set up described is impossible for temporary use of a "normal" edge mill.

Some later issues did have edge laps that were VERY hard to locate because the punch diameters were well controlled so that die length could be matched with circumference perfectly.

The coin that is pictured is a counterfeit and it was edged before it was struck on a flat press.

Regarding the SG at 10.52 - that is too high. Also check your scale. Most digital scales that have 4 place read outs have instructions with fine print that indicates an accuracy level. Check that out because I have see some cheaper scales that read out to 4 places with up to a 2% accuracy limit which is worthless for SG. Precision is the name of the game. If your 4 digit scale cost under $1500 new you can bet it is not accurate enough for two decimal SG's.

I bought a very nice and accurate analytical balance at a sheriff's confiscation sale. Drug dealer scales are confiscated and sold at auction. A typical high school lab level scale with three beams is most common. That scale which is accurate to 1/100th gram will give you 1 place SG results and is accurate enough to detect debased counterfeits. The 4 beam balance that I own cost a small fraction (about 5%) of the original price and is a college lab level (or professional lab model) accurate to 1/1000th gram if placed inside a glass cabinet to preclude air movement. I normally do not use that set up it is overkill. I think the scale must have been stolen but since the sheriff sold it I am off the hook - I hope.

Coin silver should test 10.3 (or 10.31 with weights accurate to 1/1000th gram). Just because you round the math to 2 decimal places does not mean your results are accurate to two decimal places. I suspect once you take into account scale accuracy that you may have a result accurate to +/- 0.5 so that your coin may be anything from 10 to 11. But 10.52 is far too high for coin silver.

Regarding alloys used to mimic silver. Since the 1880s thieves have learned that a lead tin alloy can be made easily and cheaply to exactly match silver density. It is the basis for the stuffed 8R coins that were so common in the period right before 1900. Absolutely no ring and soft - easy to shape to fit snugly in a hollowed out silver coin.

collectacoin Thank you for your remarks. I am trying to pass along what I learned. But I have been at this a long time now and it takes time to get the knack of spotting some of these errors.

By a flat press I was referring to a two die system pressing the planchet - except that the drive is usually hydraulic not a screw manually operated. There is no collar die it is just brute pressure that deforms the coin surface.

I suspect a single edger die was used which could be either round or flat resulting in a single overlap. Single die edgers always produce one lap unless a coin is intentionally edged twice. Then they often get the lap lengths wrong.

The mix of metals that is used to mimic silver is lead, tin and sometimes antimony. It is far harder than unalloyed lead but still soft enough to work easily. The color is also better and there are several ways to deposit silver onto it.

The lead tin core can not be used to make a Sheffield plate as it has far different physical properties so striking or rolling such a sandwich results in a poor coin.

I suspect your coin is simply too thick. From the pictures it is clearly too thick - unless you edited the photo and narrowed it. The proportions look off to me. You should check the thickness with a good micrometer.

You did not answer about the scale accuracy. The read out on the scale means very little if it has an accuracy of o.2% or 1%. That is a function of the chip in the scale and the spring if it is mechanical. I really only trust a balance neam scale that can be leveled and which you can examine the pivot for wear.

Hi Jfransch,

It is by Gilboy and you are right the book along with the 2 volumes of the Compendium VIII Reales Compendio de las Piezas de Ocho Reales apparently are collector items worth more than most 8 reales but as I have seen posted it is more prudent to invest money into the appropriate reference books to gain knowledge than to drift or sail into ignorance that can waste thousands on fake coins.

You are right it can become an obsession- not just the historical education you obtain but as in this regard it stimulates your powers of perception, reason and scientific knowledge â€" such as how to perform a sp test and then put it all together as a detective and hopefully produce a logical determination that stands before others to support your stance.

I also agree that there are many new areas to branch off and specialise in that is why I have decided to try and restrict myself to 8 reales as to try and cover all the reales as well as the Austrian/ German pre 1800 talers that I started to collect is impossible- at least for an old head like mine.

I only wish that I could download every ones knowledge on reales especially yours and Swamperbob's years of experience into a section of my brain. ( not saying that there are others that do not know just as much or more â€"just I have just started to trawl this forum and not that you both seem to be forefront in regards to 8 reales).

It is frustrating as it seems it will take years to get up to speed on just the many different mints and their designs and abnormalities â€" not to mention the counterfeit in that was down by in th e1800 and even prior if my memory serves me correct.

I have attached a drawing on the edging machine that apparently was used around 1772 â€" it shows long bars that were engraved to do the edging but I cannot seem to discern if they were long enough to produce just one edge by reversing the movable top engraving bar to support my theory. Most likely Swamperbobs reply is 100% correct that the bars would not be produced long â€" I suppose it is the rebellious sceptical gene in me that need to exhaust all possibilities so I apologise Swamperbob I should just listen to your years of experience- Most Of us Aussie convicts have hard heads.

I have just started to skim through my copy of the The milled Columnarios Of Central And South America, Numismatic history of Mexico from the pre-Columbian epoch to 1823 and it was interesting to read the following;-

"Yet whereas no limit appears to been fixed for each denomination in England , in Spain they were set out in detail though it is very possible that the limits were observed with lips more than with the heart and mind.
For silver coins they were: 8Rs Up to 4 grains (0.1996g) 4Rs Up to 3 grains (.01497g)......"

"In the Spanish dominions on the other hand, by the order of 9 June!728, lightweight coins were put aside for the payment of staff salaries(!) and, should any mint have surplus "febles", it could send them on to less fortunate sister intuitions."

"The diameters of the coins rarely varied but the thickness was determined by the number of coins that had to be obtained from a given quantities of metal."

Very interesting to note that weights may not of always been as strictly enforced as some state especially when mints were privately managed and not by the Spanish State as in later years even though there was severe penalties if caught.

The Author also makes a comparison to that of England when the moneyers customarily struck a quarter of the guineas several grains too heavy and another quarter too light. Only the correct and lightweight coins passed into circulation with the Gold merchants collecting the heavier coins and reshipping them back for reminting at the correct reduced weigh which resulted in them picking up 2 or 3 per cent profit on each coin. Apparently the practice was given the nick name- "Come again Guineas"

Anyway thanks for the welcome I hope I do not outwear it with too many questions.