Rotated dies (looking for some insights)

kurtdog

OK, this is how I do it. Stand the obverse straight up in the 2x2, securely staple it in, then flip the coin N-S. That's how I measure it. All it requires is a knowledge of how the obverse stands, N-S.

OK, question: supposing I have a 90 degree CCW, how do I know that's not really a 270 degree CW?

Related questions: which die is rotated, or can't one tell, or can both dies be rotated, simultaneously?

Or, what about just this: how do rotated dies happen? I'll take it from there...

goodmoney4badmoney

The rotation description should be to 180 degrees CW or CCW in my opinion. There is almost always no way to know with die was actually rotated.

mcarney1173

Usually, any coin is somewhere between 0 and 180 degrees.

coindeuce

Die rotation for U.S. coin production would occur exclusively on the anvil die.

kurtdog

OK, 0-180, that's good, that's how these should be described. I guess I wasn't thinking...

For coindeuce: why would the anvil be the one to be apt to be rotating; also, can one assume the hammer will always hold the obverse and the anvil will always hold the reverse? If you know...

CaptHenway

<< <i>OK, 0-180, that's good, that's how these should be described. I guess I wasn't thinking...

For coindeuce: why would the anvil be the one to be apt to be rotating; also, can one assume the hammer will always hold the obverse and the anvil will always hold the reverse? If you know... >>



The assumption is that if the hammer die were loose enough to rotate, it would fall out.

However, some hammer dies were simply mis-set in the press already rotated. Look at how common rotations are on 1913 Buffalo nickels. If you assume for the sake of argument that the reverses were normal, the obverses are rotated so that the date is at the "bottom" in the coin press. In other words, a press operator used to setting the obverse dies in the press so that the dates were at the bottom just kept doing so on the Buffalo nickels, even though the date were now off to one side a bit.

The almost exactly 180 degree rotations on some 1864 cents and two cents are logically dies that were mis-set, not rotated. Therefore, you cannot assume that it was the anvil die that was rotated.

TD

errormaven

<< <i>Die rotation for U.S. coin production would occur exclusively on the anvil die. >>



Your statement, while intuitively sensible, is invalidated by the available evidence.

In a simple rotated die error it is impossible to determine which die rotated. However, in complex and compound rotated die errors (where the rotation is combined with some other press malfunction), it often is possible to identify the culprit. And it is always the hammer die.

kurtdog

CaptHenway, I had never considered a rotation resulting from a die that had been simply set wrong. I'll have to remember that. I had always just assumed these errors had resulted from a die or dies that had "loosened then twisted" some from all the repeated pounding.

Errormaven, when we "measure" these rotated dies, do we normally (read as, barring any known extenuating circumstances) do so relative to a properly aligned obverse die? That's how I learned it. I have a "marked up" half of a 2x2 I use as a "template" to estimate the degree of rotation, and I simply superimpose that on the reverse of the 2x2 with the coin in it.

errormaven

There are at least three potential sources for a rotated die error:

1. Incorrect installation (generating a fixed rotation)
2. Incorrect grinding of "flats" or other guide marks, leading to incorrect installation (again, producing a fixed rotation).
3. A loose die (leading to a dynamic rotation).

When measuring the extent and direction of a rotated die error, the longstanding convention is to measure the degree of rotation of the reverse face relative to the obverse face. The latter is always assumed to be in the correct position. I must again emphasize that this is simply a matter of convention, not a presumption as to which die was actually out of position.

-- Mike Diamond



<< <i>CaptHenway, I had never considered a rotation resulting from a die that had been simply set wrong. I'll have to remember that. I had always just assumed these errors had resulted from a die or dies that had "loosened then twisted" some from all the repeated pounding.

Errormaven, when we "measure" these rotated dies, do we normally (read as, barring any known extenuating circumstances) do so relative to a properly aligned obverse die? That's how I learned it. I have a "marked up" half of a 2x2 I use as a "template" to estimate the degree of rotation, and I simply superimpose that on the reverse of the 2x2 with the coin in it. >>

kurtdog

Understood perfectly, Mike. We have to measure these in some way, and barring any exceptional knowledge relative to the particular rotation in question, convention simply has it that we measure them as you explained.

This thread certainly opened up my eyes some, guys...thanks!

CaptHenway

You are welcome!
TD