How long do proof silver coin dies last?

Goldminers

Someone with Mint knowledge please say how long do modern silver proof dies last in terms of actual coins minted on average.

I see a lot of variance in modern coin proof PR70 coin quality and MS70 as well.

Since the proofs usually get struck 2 or more times I assume the dies do not last as long. So please factor that into the answer.

I have looked at a lot of modern coins and have seen a lot of variances in surface finish on proofs, even PR70's by PCGS.

Sometimes I think the ones I buy last before grading are the ones struck first, and the dies and coins look sharper. This can make a difference if you focus on it.

I think the First day sold may actually be the last struck with the worn die? What a country!!??

Unknown

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Sonorandesertrat

I strongly suspect that die lifetime will strongly depend on:
1. Design details--higher relief would require greater striking pressure (two strikes per coin).
2. Diameter of the coins to be struck--greater diameter would probably require greater striking pressure. There isn't much to support a die near its edge. Bigger dies likely fail more often, all other things being equal.

I would very much like to read Carr's thoughts on the die lifetime issue.

pbj

@Elemint - thank you for the video, "How It's Made" is one of my favorite shows. I have seen the minting process for "classic" business strike coins described in books, but the modern proof minting process shown in the video is fascinating. I've never seen video of the steps involved in the process before.

I was interested in learning whether the differences in terminology between eg: the Morgan minting process and the modern proof minting process shown in the video are the result of a change in terminology, or a difference related to the Canadian process.

Specifically:
1) no use of a "hub" in Modern Process (MP).
Larger brass model is reduced to coin
size matrix(-) equilalent to master
die(-) in Historic Process (HP).
[In HP, larger model galvano electrolytic
plate(+) was reduced to coin size to make
hub(+) which was used to make
master die(-) which was used to make
working hub(+).]
2) matrix used to make punch(+)
equivalent to working hub(+) in HP.
3) punch used to make die(-) in MP
equilalent to working hub used to make
die(-).

To simplify-
MP larger brass model - >
matrix(-) - >
punch(+) - >
die(-)
HP larger plate(+) - >
hub(+) - >
master die(-) - >
working hub(+) - >
die(-)

 First, have I got it all right? Second, anybody know about the terminology differences? 

Mitchell

Here is an admittedly non-statistically significant sample from the 1995-1996 Olympic silver proof coin dies.
The COAs in my collection (and I don't have all of them) say:

• 1995 $1 obverse Tennis with 554 strikes: retirement reason: date change
• 1995 $1 reverse with 1,000 strikes: retirement reason: starburst
• 1996 $1 obverse Runner with 3,023 strikes: retirement reason: worn
• 1996 $1 obverse Track with 300 strikes: retirement reason: starburst
• 1996 $1 obverse Gymnastics with 1,200 strikes: retirement reason: starburst
• 1996 $1 reverse with 2,164 strikes: retirement reason: date change

Hope this helps.

davewesen

it would be interesting to know how the 90% silver strike numbers compare to the clad strike numbers for proofs on the dimes, quarters, and halves for the years that had both silver and clad proof sets.

BackroadJunkie

According to the Mint, a die for proof ASE's are good for about 2000 coins. They are also not necessarily replaced in pairs.

Normal silver coins are of lower relief, so they may last longer...

ricko

There are obviously many, many variables in coin production - metal, design, coin type etc....
I am sure that modern minting processes are highly documented and predictable. Having been involved in volume manufacturing, I know that process predictability is critical to cost control and quality. Cheers, RickO

Broadstruck

Short run retired proof dies often went onto striking business strikes until fully exhausted.

Cameonut

I know the OP asked about modern proof die life and mentioned PR70 grades, so I'll assume very recent production. I do not have any recent data from the mint, but here is some data from 1954 - I would think that technical improvements could extend die life above the data below.
Obverses only - reverse die life tended to be similar
50c 4,408/die
25c 5,020/die
10c 4,605/die
5c 5,278/die (included for completeness)
1c 6,135/die (included for completeness)
Data from the "Record of Domestic Dies for the Year Ending December 31, 1954" signed by the Assayer and the Superintendent of the US Mint

Goldminers

Thanks all for some great answers.

The main thing is I see there are a lot more dies that have to be made for a 200,000 proof mintage then I thought, as it seems 3,000-6,000 coins each is not unusual.

So coins like the last first spouse golds probably were all basically struck on only one die.

Based on this early set of data, the reverse proof set at 200,000 mintage may have used about 40 dies to finish minting each coin.