This is from a chapter in Rob Ezerman's forth coming book on "The Eisenhower" dollar. The staff of MADdieclashes.com wish to thank Rob for letting us add this important information to our site.

"The majority of 1971-D Ikes and a substantial minority of 1972-D Ikes show clash images, often heavily abraded (“repaired”). Other than 71(P), 73(P), 74(P), and 73-74 Blue Pack and Proof Ikes, the entire series has multiple examples of clashed die Ikes that tend to fall within several “families” of similar images.

When two dies clash, the fields meet with a “slap” or a “bang” because a planchet was not fed into the chamber between the dies as they come together. The fields of both dies thereupon sink a bit into the incuse devices on the opposite die. The periphery of incuse devices, with the sharpest cut off in the field, tends to leave the strongest clash images on the opposite die.

Clash images are also heaviest adjacent to a major device on that same die and then taper off rapidly since toward the center of a die’s field the die-clash pressure is spread out more uniformly than when nearing an incuse device.

In other words, the closer to the edge of an incuse device, the more the clashing fields experience locally increased clash pressure because the field overlying the incuse device is not being supported in all directions by the opposing die’s field.

Clashes images are usually single but may be multiple if the dies continued to slap together before planchets resumed their normal destination into the coining chamber and the press failed to shut down."

"THE OBVERSE IKE DIE CLASH IMAGES

TALON HEAD - Ike die-clash images are linear with one major exception, the “Talon Head”, a dagger-like image that can be found on some clashed Ikes in the center of Ike’s temple. This clash image is unique because it is solid and because it is caused by an elevated nubbin on the reverse die that rises above the level of the reverse die’s field. When the dies clash, this nubbin reaches into the incuse cavity of Ikes temple and indents the obverse die. Although the nubbin is round, the talon image is sharply bordered, probably a “splash” or “shock-wave” effect.

This round nubbin corresponds to the very deep rounded depression between the Eagle’s Legs. We call it the “Leg Hammer”. There is a secondary hammer between the Eagle’s left leg and tail which we call the “Tail Hammer”. It can leave a down-pointing little spike close to Ike’s hair which sometimes is continuous with a larger almost rectangular image. The photograph at the very end of this chapter shows both hammer images doubled from a “two-bang” clash.

HAIR LIP - Linear clash with the leading edge of the Eagle’s right wing, usually comes off Ike’s lower lip unless the clashed dies were rotated.

VOLUNTEER - From the leading edge of the Eagle’s left wing clashing where the truncation of Ike’s bust meets the field. Normally emerges at the F of FG. Named after volunteer plants that grow uninvited.

UPSIDE DOWN U (“UNUM”) - A less-than-common letter clash from the first U of UNUM. Very desirable thanks to the rare letter clashed Morgan Dollars that are highly prized."

"THE REVERSE DIE CLASH IMAGES

JAW LINE - Linear image to the South and East of the Earth, from Ike’s jaw.

MOON LINE - From the top of Ike’s head clashing on the lunar surface which is almost at field level. “Multi-bang” clashes may show clearly in the inside of the large left crater which is usually not abraded."