Ptolemaic Bronzes - Central Depression

someone wiser in the ways of coins than I said recently that they may have been used to as a place for pinchers to grab the flan to flip it.

I have long subscribed to the 'theory' that the standard explanations of coin manufacture in ancient times do not adequately take into account the large sized AE's which are best represented by the Ptolemaic issues and the Roman Imperial sestertius as produced from the mid first century until the mid third century. These were very much 'prestige' issues and were obviously much more complicated to produce than the tiny late issues or coins of silver and gold which are relatively easy to stamp.
For most small sized planchet production Moe Larry and Curly will be sufficient for the actual manufacture. One fellow is bringing in the raw materials and placing the blank another handles the die placement and the last (idiot) swings a sledge hammer. Good enough.
But for banging out high relief large ounce sized coins in orichalcum I simply don't believe it ! As circumstantial evidence I would point out that nothing similar was produced in the type of quality seen until the invention of the modern coin press. Even screw type presses are noticeably low relief and cannot hold a candle to a high relief issue of Antoninus Pius. Specifically the double portrait (Pius & Marcus) Sestertius I own which measures 1/8 inch of relief distributed over both sides.
The central 'dimple' seen on Balkan issues and the Ptolemaic bronzes likewise give me pause. I don't really like either explanation. Of the 4 Ptolemaic AE I own and the seven Balkan coins I have not one has the dimples lined up within several millimeters. The smaller ones have closer alignment but they are all but impossible to hold up using two ballpoint pens (which fit rather neatly)
The largest Ptolemy I own (67.63 grams) shows obvious signs of hammering around the edges. The next one down in size (35.67 grams) shows 'tool' marks similar to a steel cutting tool shaving a chamfered edge all the way around.The next down (31.68 grams) has a similar type edge but the tool markings look much more rasplike. Perhaps a combination of both was used. Lastly my little fellow (9.34 grams) which has a relatively 'normal' albeit angular edge which shows minimal signs of having been being cleaned up.

At first glance the little guy doesn't appear to have a 'dimple' but it does.




The big brother (35.67) has something very interesting though



The area of the dimple is shattered. Something 'violent' occurred which literally blew out the bronze leaving a jagged wound.

The other (31.68) has the best preserved dimple and also shows something very intriguing to me.



My father was a tool and die maker and operated a small manufacturing business for 35 years. 'We' produced a variety of hardware parts used in communications headsets and a variety of other products. Often when making something at a very fast rate (sometimes measured in thousands per hour) springs are used to expel a piece in order that the new material coming in does not result in two pieces getting formed and crushed together. For tighter spaces it is necessary to use a polished round headed pin with a spring adjustment below. If the spring gets broken or caught somehow, the smooth pin instead of expelling the object cleanly will instead leave an imprint or a 'dimple'.

Look closer ....




I see a hole made by a rounded pin mounted on the inside of a die with a raised donut like area around it caused by it being slightly too deep. Whether this pin was on a spring I can't say but I am almost certain it was present when the coin was stamped.
One of the consequences of the recycling of the old sestertii in the later Empire was the embrittlement of the orichalcum alloy. The evaporation of the zinc in the smelting process gradually resulted in fractures becoming the norm in late Imperial sestertii and eventually the metal was of the same appearance as bronze. It did result though in a change in the production of the blanks. Brittle alloy and the blanks being used suddenly become squared instead of round. Brass can be like hard bubblegum when trying to cut. Embrittled bronze is easy to chop into pieces. The standard theory is they used a chisel to chop up stips. Could be. But being clever fellows they might have built a continuous shear powered by a rotating 'cam' and simply hand fed the strips into the 'machine'.

Of course these things would require something they did not know how to make. Steel.

Recycling bronze gives you an altered alloy that is hard and brittle. They could hardly have understood the metallurgy or why the zinc was disappearing. Recycling broken iron weapons and tools gives you something else though. The Romans did not know how to make steel. But they did have it in stock. If you remelt the iron enough times the carbon will slowly build up from exposure to the coal fire and eventually you will get steel. Hardly high grade tool steel but by pure accident you will eventually get some alloys that will have enough of the right trace metals to make some blades that they hardly could not have noticed were head and shoulders above the weapons carried by some new recruit ! These weapons might even have become famous and were surely handed down as family treasures.

The idea that a machine or machines were used to make coins is not considered probable by most people. The idea that the ancients had any clue about precision machines is rather silly idea isn't it ?

The Antikythera Mechanism



"The Antikythera mechanism (/ˌænte¨ke¨ËˆÎ¸eªe™re™/ ant-i-ki-theer-e™ or /ˌænte¨ËˆkeªÎ¸e™re™/ ant-i-kith-e™-re™) is an ancient analog computer designed to calculate astronomical positions. It was recovered in 1900- - "1901 from the Antikythera wreck, but its significance and complexity were not understood until a century later. Jacques Cousteau visited the wreck in 1978 but, although he found new dating evidence, he did not find any additional remains of the Antikythera mechanism. The construction has been dated to the early 1st century BC. Technological artifacts approaching its complexity and workmanship did not appear again until the 14th century AD, when mechanical astronomical clocks began to be built in Western Europe."

FVRIVS RVFIVS & Sap: I am indebted to your answers and reasonings. Interesting.
Ta!