The incomplete punch (incomplete clip) is an infrequently encountered
planchet error. It occurs when a punch (blanking die) fails to
penetrate the coin metal strip completely. If the strip fails to
advance properly, and a blanking die slices through the same general
area a second time, you end up with a blank that carries a deep
semi-circular scar on both faces.
The illustrated 1974 Jefferson 5-cent coin shows a classic
incomplete punch. Each face displays a deep, sharply defined curved
groove in the same position. Each groove penetrates the surface and
appears on the coin’s edge where the groove terminates. The depth of a
punch mark will naturally vary from coin to coin.
The appearance of an incomplete punch will be very different on an
unstruck blank or on the unstruck portion of an off-center coin. A
blanking die doesn’t so much slice through the coin metal strip as
push through it. This is because the blanking die is not a circular
blade; it is a flat-faced cylinder with a relatively narrow central
tunnel that helps dissipate heat.
If the battery of blanking dies doesn’t penetrate the strip
completely, it leaves a series of depressed circles in the upper
surface of the strip and a corresponding series of elevated circles on
the lower surface of the strip. After lagging behind and being punched
through a second time, this portion of the strip yields a series of
blanks, each of which shows a step-down on its upper surface and a
step-up on its lower surface. When the blank is struck, the steps are
erased and all you have left are two grooves.
Error dealer Jon Sullivan recently presented an off-center,
copper-alloy cent whose unstruck portion carries a defect that shares
many of the characteristics expected of an incomplete punch error (see
photos). It was erroneously described by a major grading service as
having a “double indent.”
The idea that this planchet was sandwiched between two planchets
when struck is ludicrous, as neither face shows an indentation from an
unstruck planchet. Instead, the planchet is bisected by a curved
disruption that divides it into a crescentic half and an oval half.
The oval half has been pushed in on one side and pushed out on the
The metal has been visibly sheared through at the sharp step-down
from the crescentic portion of the planchet to the oval portion. This
presumably represents the original upper surface of the cent strip.
The other side of the coin shows a sharp step-up from the crescentic
portion of the planchet to the oval portion. This presumably
represents the original lower surface of the strip.
A tiny off-center uniface strike is located midway along the outer
curve of the oval section of the planchet. The outer portion of the
last two letters of GOD can be seen at the tip of the struck tongue of
metal. These die-struck obverse elements occur on the same side as the
pushed-out portion of the planchet. This is not surprising as almost
any planchet has a 50/50 chance of arriving in the striking chamber
with its original down side facing up.
Some features of the planchet defect are not entirely consistent
with an incomplete punch error. The two halves of the planchet should
be parallel to the same horizontal plane; instead, the oval portion of
the planchet meets the crescentic portion at an angle of around 30
degrees. This almost certainly represents damage that occurred after
blanking. Such damage is also unsurprising, as the punch almost
completely penetrated the strip, leaving a weak connection between the
two halves of the planchet.
Also, both halves of the planchet should have flat surfaces, top and
bottom. Instead, the “upper” side of the oval portion is distinctly
concave in vertical cross-section while the “lower” side is convex. My
guess is that the same mechanism that produced the bend also squeezed
the oval portion of the planchet into its convexo-concavo topography.
The upsetting mill is one candidate. If the bowl-like shape isn’t
damage, then we’d have to invoke an unlikely, ad hoc explanation
involving a mystery cylinder with a convex face.