Edges Of Milled Pillar Dollars

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.

Merci MathieuMa pour le lien. It is very informative I probably would of never stumbled upon it or at least not for who knows how long.

Mathieu - I had seen an earlier version of that page but it is far better now with a lot of GREAT pictures.

The edge dies in the pictures are deeply grooved to retain the blank and the set up was only adjustable for diameter with wrenches. They must be from a continental mint - they are slightly different than colonial (Mexico City) but identical in principle and operation. It also answers why Cuds can be retained and rolled in on BOTH sides of a coin.

Interesting. I will study and copy those pictures for detailed review. Are they all copy right protected? Do you know how to get permission to use them?

I just wrotr as you suggested. I wonder what he got to see in Mexico most of the collection is not open to the public.