Just Read Something Interesting About Larger Roman Coinage.

We simply don't know exactly how "the Roman mint" worked at every stage of Roman history, We have a few detailed accounts from specific slices of time, but a full detailed history was either never recorded, or has now been lost. I'd probably lean towards "never recorded", as minting of coins was not only a closely guarded trade secret, but a state secret - after all, if it were widely known how to make coins, then some enterprising criminal types might just try to make their own.

That being said, we do have some records of what mint operations looked like at certain time periods - such as during the reign of Hadrian, when large finely detailed bronze and brass coins were being struck. There is no mention anywhere of any device resembling a "drop hammer", or anything other than the sheer brute force of the malliatores ("hammermen"). All of the surviving illustrations and depictions of ancient Roman coin-making show a three-man team at work: the guy who picks up the finished coin and puts down the next blank (the suppostor), the guy carefully placing the hand-held reverse die on top of the blank (the signator), and the big guy with the hammer (the malliator).

Some of the surviving illustrations of mint activity (such as this fresco from Pompeii) show workers taking things out of a furnace with tiny tongs. It's debated whether these are coin blanks being heated, or coin dies being forged and hardened. We also have the curious case of "centration dimples", indentations found on certain large bronze coins (both Greek and Roman) which look for all the world as if some tongs had grabbed onto the coin blank while it was so hot it was semi-molten. Numismatists have long argued about what centration dimples are, and how they were made; the "tong-marks" hypothesis is a strong candidiate.

There thus seems to be strong evidence that at least sometimes, it was likely that tougher-metal coin blanks were heated to softness before being struck. The main argument against the Romans doing this as routine practice seems to be that it must have been so time-consuming and labour-intensive to heat up each coin blank that much prior to striking, that it doesn't seem it could have been viable from an economic and time-budget perspective.

Either way, we are left to speculate about what kind of mysterious magic was at work in the Roman mint: whether it was some powerful drop-press for which there is zero actual archaeological evidence, or an equally evidence-free method of heating a whole bunch of copper blanks to near-melting very quickly and cheaply.

I would think some smart materials scientist would be able to tell the thermal history of the coin (how hot it was likely heated at the time of forging). But that would mean destroying some coins to prep them for the scanning electron microscope. And if it were a two step process (forming blanks, then reheating to hammer the coin), the interpretation could get kind of difficult.
But it would be shocking if there were never a PhD thesis produced om something like this.

A hammer of a given weight in a contraption powered, say, by gravity will always strike with the same force.
On the other hand they didn't have thermometers to enable them to always strike the blank at the same temperature.

Lemme get this straight .
It is reasonable to assume that Roman engineers constructed machines capable of hurling cannon ball sized 'ballista' upwards of a quarter mile and impacting targets at over 100 mph
Yet we are to assume they relied on "Moe Larry & Curly" when issuing one and two ounce bronze coins and medallions

Sorry .
No sale !



https://romanobritain.org/8-militar...rtillery.php

Yet whenever I have seen ancient coin minting "technique" demonstrated it has always been drachm sized planchets utilizing high purity (usually silver) metal
But I would really like to see this 'sestertius' of mine replicated

37mm 45.90 grams




But I won't hold my breath either .

The British TV documentary series Time Team did an episode with some experimental archaeology regarding the making of large bronze coins in ancient times. Now "experimental archaeology" in this context is really just "taking modern replicas of the tools we know the ancients had and trying to use them", without actually using a time machine to watch how ancient peoples actually used them, so given that caveat, the show came to the following conclusions:
- Cutting blank planchets off of a tube of copper, "cob-style", simply wouldn't have worked - copper is too tough to make a clean cut with ancient technology, and the amount of labour needed to round off and flatten the blank properly simply couldn't have been time-effective. As such, individual casting of blanks seems more probable.
- Cold-striking a copper or bronze coin using the big-guy-with-a-hammer method simply didn't work - virtually no detail came through onto the finished coin, even after multiple strikings.
- Heating the blanks before striking worked a treat and created very authentic-looking coins.

"We tried striking coins cold and it just didn't work" seems to be the consistent result from experimental archaeology; assuming the archaeologists haven't missed some obvious flaw in their reasoning, the resultant conclusion is that they must have been struck hot, despite the extra care and labour this would have had to entail compared to cold striking. Even hot-striking requires a 2 or 3 blows of the hammer to fully strike up the details on a large bronze coin, which perfectly accounts for the doubling often seen on large Ptolemaic bronzes.


We have plenty of physical and graphical evidence of Roman military hardware. We don't have any such evidence for the use of drop-hammers or similar mechanisms to aid in coinage production, despite having a few surviving depictions of mint activity.

Could the ancient Romans have built a coin press? Sure. We know they had powerful water-powered drop hammer technology because we've found physical archaeological evidence for them at mine sites in Spain and Wales, used for crushing ore. Did they use them for striking coins? There's no evidence, so until and unless some kind of actual evidence that they did so comes to light, we have to assume they didn't - that's just how archaeology works. Archaeology is a science, so it's all about what the surviving evidence states; discussing how things "might have been" without such evidence is really just writing historical fan-fiction. Maybe at some point in Roman history, somebody with access to water-powered drop hammers tried to experimentally adapt those drop-hammers to strike coins; maybe it didn't work well, or maybe they concluded it was simply easier to buy a couple of hefty slaves and go back to making coins the old-fashioned way. If this happened, no physical evidence survives and no written records either. All we can conclude from the archaeology is "It doesn't appear to have been used".

It's not entirely unlike the question of the ancient discovery of the Americas. "Could the Romans have sailed to America?" Yes, technically, we know from archaeology and written records that their ships had that capability. "Did the Romans sail to America?" Well, there's no physical evidence one way or the other for this either in America or in the Mediterranean, nor in surviving written sources, apart from the old "absence of evidence" argument (for example, if the Romans had visited the Americas, why were there never any pumas or jaguars in the Colosseum?). So we have to presume the answer is either "No, they didn't", or "If they did, they somehow did it in such a way that it left no permanent mark on Roman society".

Around ten years ago I posted here a Britannia reverse type As of Antoninus Pius
While I cherished the piece ( great price !) I acknowledged the inferior workmanship in 'style'
In fact it is commonly speculated by "numismatists" that the issue type may have come from a traveling mint operating within the province itself
Having concentrated my personal collection on AE's I wondered aloud why these "inferior" types seemed limited to the copper As denomination while the glorious sestertius (and Dupondius) issued seemingly from Rome alone ?
Brittania as we know for certain was the Roman source for tin
(Cyprus was famous for copper !)
But why would the local being sourced for the tin to make bronze (80% copper about 20% tin with trace amounts of lead and
nickel)
not issue in bronze or the beautiful Roman 'orichalcum' ?
Having experimented with copper and bronze the answer to me seemed simple
Copper is rather malleable
Bronze and/or brassy orichalcum most definitely is not !
Possibly would have not issued due to the difficulties involved ?
They were reasonably close to the source of the tin used to produce a very strategic alloy
So why not use it ? Instead they imported copper ?