For coins not fully struck up, is it the reverse that is always better struck because of the mechani
Longacre
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I always read that some coin designs come not fully struck up, basically because of a design "flaw" where the deepest parts of the dies are opposite each other. I believe (and I could be wrong), that coins are stuck where the reverse die is stationary and the obverse die moves and strikes the planchet. Do not fully struck up coins usually show weakess on the obverse, or does it just depend on the coin design? Also, does the minting process (if I described it correctly) factor into whether the obverse or reverse is fully struck or not (assuming a flawed die design)?
Always took candy from strangers
Didn't wanna get me no trade
Never want to be like papa
Working for the boss every night and day
--"Happy", by the Rolling Stones (1972)
Didn't wanna get me no trade
Never want to be like papa
Working for the boss every night and day
--"Happy", by the Rolling Stones (1972)
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<< <i>For coins not fully struck up, is it the reverse that is always better struck because of the mechanics of minting? >>
My hasty, off the top of my head reply is no.
The first example/coin which comes to mind happens to be among my favorite types - the 1796 Quarter. They often/usually display very good obverse design detail, but partially weakly struck eagles (particularly on the head) on the reverse. I will (hopefully) go find images with which to illustrate my point. Back at you soon.
Edited to add:
obverse image
reverse image - see eagle's head
When a coin is 'struck' in a coin press, the blank planchet is squeezed between the opposing dies. Pressure is distributed equally to the planchet surfaces by both dies, and it does not matter which die was 'moving' and which die was stationary. It is perhaps better to think of a coin as being squeezed by the dies, rather than 'struck', especially with the old, slow hand screw presses. 'Momentum' of the dies has little to do with it.
I would think that a better reason for details not being fully stuck up would be, as you mentioned, that the deepest recesses of the dies, and therefore the points of highest relief on the coin, might be directly opposite each other, so there might not be enough coin metal to flow into the recesses.
Also, let's suppose that one die has a detail of very high relief (deepest recess on the die), and that the same point on the opposing die WAS NOT necessarily the point of highest relief on that die. If the dies came together with insufficient force, the point of highest relief on one side would not strike up fully, while the point directly opposite, with lower relief, likely would. It is a matter of relative degree. Whatever the force exerted by the dies, it will be sufficient to strike up details of a certain depth, or relief. If the details on one side of the coin are high relief, and the details directly opposite on the other die are shallower, the shallower side gets the coin metal.
One can get a much better idea of this concept by making transparencies of both obverse and reverse dies for a particular coin, laying them on top of each other, rotated 180 degrees, and looking to see where high points in the design align.
<< <i>For coins not fully struck up, is it the reverse that is always better struck because of the mechanics of minting? >>
There is extremely little difference between the forces on the anvil die side of a planchet and the hammer
die side. Essentially this difference is the weight of the planchet. But with 10 to 150 tons of force, this
would be far less than the more important factors like design and relief. Probably even planchet temper-
ature would be of more consequence.
Didn't wanna get me no trade
Never want to be like papa
Working for the boss every night and day
--"Happy", by the Rolling Stones (1972)
As MrHalfDime said, the most likely reason for weakly struck areas is from lack of metal flow to the highest points on the design, which will affect the opposite area of the coin as well. Also, if the dies are set (shimmed) slight off parallel at strike, one portion of the coin will have a good strike, and the other portion will be weakly struck common to both the obverse and reverse. This is what I believed happened with 1806 O.105, 106, 107 where the drapery lines have little detail, and the opposite reverse stars and clouds are never fully struck 1806 O.106 nysoto registry.
Other reasons for weak strikes on early US coins are sunken dies such as this current Heritage auction example 1806 O.119a sunken reverse die, shattered dies 1806 O.114a, and weak striking pressure, since all screw press strikes had some variation in striking pressure.