Question About Die Pairings

[Guest]

Q: Is it possible during a run to swap out only the hammer die... or the anvil die and leave the other in place? It would seem the logical thing to do if one or the other cracked or became otherwise unserviceable.

I ask this because I've noticed on some occasions that reverse die markers are used to help identify some DDO's.

Thanks.

-George

[simonm]

yes. One example is the 1972P Die 4. It has been found that the reverse die was paired with both the Die 4 obverse, as well as a normal master die obverse.

[thecentcollector]

yes. One example is the 1972P Die 4. It has been found that the reverse die was paired with both the Die 4 obverse, as well as a normal master die obverse.

Actually Simon, the Die #4 reverse was found with 3 different obverse dies (MDO, DDO #4, Non-MDO)

[jallengomez]

It's not only possible, it's very common.

[GrumpyEd]

I ask this because I've noticed on some occasions that reverse die markers are used to help identify some DDO's.

If you look at some listings you'll see they list things like when one die is swapped out at.

I've always wondered about their procedures. Like most factories have operators for a task. If a problem comes they follow some procedure. So I've wondered if the press operators also do polishing or brushing or they get someone else to do it. Or if a die fails if they replace it or someone else does. Or if dies are serviced in pairs, like if one fails do they swap out the pair then offline someone else services the used ones into re-usable pairs then later after servicing that pair gets put back online.

[trails]

This is commonly done when a die clash event occurs. The obverse die is much more likely to be changed out due to the damage received from the clash event, while the reverse die is more apt to be abraded to remove those clash marks. That is why we occasionally see die clash marks on the reverse face of the coin and not on the obverse face.

Also take into consideration at the end of the year when the obverse die is changed for a new date and the reverse die is left in place for continued striking.

BJ Neff

[coppercoins]

Coppercoins.com reports die changes every time we know about it. I know there are at least a dozen different listings throughout the website that show reverse die changes on obverse die varieties. One of the 1938D RPMs is linked to both a strong class 6 DDR and to a 'normal' reverse. That's just off the top of my head.

[penny man]

There is a 1960 DDR (CONECA 6-R-II-C) that the obverse was changed from a small date to a large date.

[Justafarmer]

I am of the opinion that dies are general replaced in pairs. Absent of any unusual event such as a major clash or pre-mature failure the dies remain in service for a standard period. Once this period is achieved the dies are removed as a pair and replaced, whether they have any remaining production life or not. As with any manufacturing production process - unscheduled downtime is very costly. It is cheaper and more efficient to replace machinery and parts based on their normal useful life at scheduled intervals. But I could be way off the mark on my line of thinking.

[coppercoins]

Penny man - I am unaware of any such die pairing.

Justafarmer - You are way off base. Time and time again there has been evidence of one die left on the press while the other was changed. In fact, there is at least one case that I know of where a reverse die was left on the press between years.

[penny man]

Sorry, it is actually 7-R-II-C. I don't think it is listed on coppercoins, but it is in the CONECA master listing.