Why are 1969-1972 proof sets so one-sided on Cams?

ursabear

Almost every one I've seen is Cam on the obverse and brilliant on the reverse (with the occasional frost bit (hee hee) on the reverse).

?

If it wasn't for Russ, I'd hardly have any CAM or DC Kennedies from those years...

Russ

The mint didn't use matched die pairs at the time. They might pop in a fresh obverse die and leave the old reverse die and vice-versa. They frequently used the dies far beyond what would be today considered useful life. In addition die preparation was not nearly as good as it is today.

Russ, NCNE

cladking

I believe that during that era, dies would often be worked to restore
the frost while still in the press. I assume they usually only did the
obverse die. If memory serves, they used a rubber template to protect
the rest of the die.

Techniques and practices have changed and evolved leaving little but
the coins as evidence.

ursabear

Whew!

I've found lots of nice fields on these coins, but almost never a thick frost.

The hunt continues!

RGL

Planchet quality also was very spotty, with many very poor, in these years, particularly 1970 and 1971 ...

Russ

Planchets in 1971 really sucked. I've seen so many 1971 halves with pockmarked fields it's just plain depressing.

Russ, NCNE

MadMarty

It's because and 2 sided CAM or DCAM Russ has already hoarded!