The origin of elliptical clips
- In the latest issue of Error Trends Coin Magazine, Arnie Margolis
reprints two letters he received in 1973 from Alan Goldman, the
mint's Assistant Director of Technology at that time. The letters
were in response to inquiries Arnie made regarding the original of
Mr. Goldman presents TWO scenarios, which are offered as guesses.
Arnie has publicized and supported only one of these and told all who
would listen that the favored scenario was an established fact.
In his letter of March 12, 1973, Mr. Goldman says that "Most blanking
errors occur from slippage of the strip during feeding. This causes
the blanking dies to punch part of a circle which has already been
punched before, producing a clip. If the previously punched circle
still contains its blank, then the repunch produces two clips and an
ellipse. Failure of the blank to separate from the strip can occur
if the strip is too soft and "shags" at the edge."
This scenario is very similar to the one offered by pwrwgndrvr and
The second scenario, presented in a letter dated July 5, 1973, is the
one favored by Arnie. Mr. Goldman writes: "When a new punch and die
set is inserted on a blanking press (as is done when changing from
strip for one denomination to strip for another denomination), the
initial length of strip is often fed through the press with an
insufficient blow for the punches to penetrate the strip. This is a
frequent occurrence during setup, when the tonnage is slowly
increased until a sufficient force is acheived to punch through the
strip without penetrating any further into the hole than necessary.
An excessively long stroke would limit the speed at which the press
can be run. The standard procedure is for the first several feet of
strip after a change of denomination to be chopped and returned for
remelting. Occasionally, particularly with some of the newer
operating personnel, the strip is not advanced sufficiently to clear
all the punches before the presses are restarted."
So we see that even the mint itself is unsure how elliptical clips
are created. As was made clear in a very long debate some months
ago, I favor the first scenario.