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 Replies: 55 / Views: 4,482 |
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Valued Member
Canada
93 Posts |
Hi everyone, I posted a coin before Christmas of the coin my brother was getting me. Unfortunately, I think that one got lost in the mail. It was from ebay and, oddly enough, each day the estimated date of delivery is delayed a day. It was shipped on December 15 and it's still not in. I contacted the seller last week and I'm going to contact him again. Anyway, my brother was incredibly kind and got another one from Forvm Coins. It's double struck, which I think is really cool. Here it is:  Thanks so much, Erin |
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Pillar of the Community
Italy
1790 Posts |
Very nice  . Just out of curiosity what is the weight of this coin . |
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Moderator
 United States
23731 Posts |
I like this coin type and wish I had more of them. Nice coin. Do you know Which Ptolemy it is? Here is an excellent site on bronze Ptolemy coins. http://www.ptolemybronze.com/ |
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Pillar of the Community
Italy
1790 Posts |
Echizento, all the PBB ( Ptolemy Big Bronze) I have seen have a hole through Zeus , why so ?
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Moderator
United States
23731 Posts |
There is several theory's about this. One is the the coins were turned on a lathe and the hole is where the chuck was placed to hold the coin. The other is the it was used to center the coin when it was struck.
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Pillar of the Community
United States
3443 Posts |
And then there is my 'way out' theory that it has every appearance of being a dimple left by a spring action pin
used to eject an object from a die. Such a theory requires a measure of 'automation'
which I personally believe the ancient engineers were more than capable of achieving.
My theory is not generally concidered probable.
But it works for me !
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Moderator
United States
23731 Posts |
Considering how large these coins can get makes one wonder how they were struck. It would take a very large person with a great deal of strength to exert enough force to strike a 45 mm coin and to get it perfect. There had to be some type of machine used to strike these large coins. So your theory isn't out of the realm of possibility.
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Pillar of the Community
United States
4971 Posts |
nice present, those thick ptolemy coins are awesome! here's an oblique view of my last ptolemy coin...  |
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Pillar of the Community
1121 Posts |
I wouldn't give up hope of the other one arriving just yet.
A coin (and book) was posted to me from the UK on the 13th October (postal date on article) and only arrived a week or so ago. That's 96 days in the old scale.
Nice Ptolemy! I only have one (but I do like it/them).
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Pillar of the Community
Italy
1790 Posts |
Very interesting theories going around . I will have to do a bit of research on this . How long did this series run ( did they have these by the time of Augustus's conquest of Eygpt ?)
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Pillar of the Community
United States
3443 Posts |
Forgive my 'rudeness' !
It is a nice one ! Nothing like playing with one of these in your hands ! They remind me of how I felt when my grandmother gave me a beat up and worn silver dollar when I was seven years old. That is the greatest part of owning a big Ptolemy. You are allowed to play with it ! None of this look don't touch stuff.
Back to my hackneyed theory ........
I have 3 big Ptolemys and when I try to hold it up by the dimples with 2 ball point pens ......
I can't ! The holes do not line up. Ergo it seems improbable that they were "turned" at these points.
Likewise the coins are so big that 'centering' the sucker seems unnecessary.
I do not like any of the textbook explanations.
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Valued Member
 Canada
93 Posts |
Thanks everyone! I'm fascinated by it and hope to get more. I think they have even bigger ones too. This one is Ptolemy IV, measuring 38 mm and weighing almost 49 g. Wow,Topcat, that's a long wait with lots of patience! I've had problems with things getting lost in the mail. I think at least 5 coins were lost last year. So, I now tend to det very nervous about packages not arriving within a month or so. I'm just trying to figure out why ebay keeps pushing the date or arrival back. Erin |
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Moderator
United States
23731 Posts |
Aug Max. The series started around 280 BC with Ptolemy I and last until the last Ptolemy, Ptolemy XII circa 51 BC, thought by that time they were very reduced in size. Here is an interesting article of lathe turning these coins. http://www.classicalcoins.com/flans1.html |
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Pillar of the Community
Italy
1790 Posts |
49 grams ! If the Eygptians ran out of arrows against the Seleucids , they could always sling these things at them. @Sky interesting article . And not a bad run for a series.
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Bedrock of the Community
Australia
21788 Posts |
so far as the manufacture of Ptolemy bronzes are concerned echizento has indicated that one of several plausible theories is probably correct.
The biased chamfered edges and tiny central pits are an obvious feature of these coins.
Bronze is a very useful alloy for coinage
Bronze is an alloy of copper and tin, mostly copper.
Pure copper has melting point of 1083 deg. C.
Pure tin has a melting point of 232 deg. C.
The temperature paste range of bronze is therefore between
232 and 1083 deg. C.
The ancients certainly knew how to get enough temperature to pour liquid bronze.
One theory is that bronze was poured into molds of appropriate size, and the blanks were struck after they were allowed to cool into the paste range of temperature, where the large coins could be struck with very low striking pressures.
Weight was adjusted after striking, and lathing seems to be plausible way of doing this, at a much lower temperature, but possibly still within the paste range.
Cold bronze is relatively hard.
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Pillar of the Community
United States
3443 Posts |
This is an extreme close up of a dimple. Note the raised area around the perfectly spherical dimple hole.  Now look at this one. I honestly forget the size but it is a whopper. Around 70 grams.  The area of the 'dimple' is shattered. Something violent occured. It can only have occurred during the strike. I suspect the pin fractured and the metal being work hardened by the strike literally 'blew out' But I do have an active imagination ! |
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Replies: 55 / Views: 4,482 |
Posted 01/22/2015 2:57 pm
