What happened to copper plated zincs to make die flow lines less visible

[VAB2013]

Maybe it's just me... but seems like I have been noticing that copper plated zincs up to the early 90's have much stronger die flow lines at later die states compared to later in the 90's and Shields. Seems like up through say 1993-94 the die flow lines are much stronger. Could it be that the dies were being used longer then?

I wondered if the striations were just covering up the flow lines, but I don't think so. Could it have something to do with when the Ball jar company started supplying the Mint with planchets?

[GrumpyEd]

Viv,

My guess is it's more than one thing.

Around the time they changed to zinc they also changed the obv die variety, it changed from ODV 31 to ODV 32. That is why we have LD and SD 1982 cents but somehow implementation was a mess so we ended up with copper and zinc of both types (SD is ODV 32, LD is the older ODV 31). I assume the intent was ODV 32 to be used for zincs.

I assume that they thought ODV 32 was better for zincs. Zinc is a harder more brittle metal so they probably thought that a shallower design with less relief will compensate for the harder brittle zinc. Apparently it wasn't a cure all, they were still not good and formed ridge rings and seemed to wear in a messy way. On top of that their plating was not great so they look even worse with bubbles, blisters, split plating.

I don't know why but like you said they also seem to have brutal polishing.
They must have worked for years (into the 90s) to improve it. They stuck with low relief and must have been tweaking everything, plating, planchets, pressure and maybe presses and die metal. I'd assume they tweaked to get good die life and solve the wear/ugly issues. Whatever they did seems to have worked, the later and modern ones are better.

It also seems the later ones have less messy polishing and less severe ridge rings. Maybe the tweaking did reduce die wear, maybe less pressure or press changes (setup or the presses themselves) or something made less severe clashing so less brutal polishing was needed. We still can find clashes but I see a lot less extreme brutal polishing now than the early zincs had.

[makecents]

Viv, the timeline you threw out there, immediately made me think about the single squeeze process being introduced at the end of the 90's. I don't know if this would have any affect on flow lines though.

[jallengomez]

They went to single squeeze in 1986, so that would have been prior. It's a good question, and I agree with Ed that there were probably several factors, but the lowering of the relief on the dies probably had a lot to do with how they degraded over time.

[makecents]

They went to single squeeze in 1986, so that would have been prior. It's a good question, and I agree with Ed that there were probably several factors, but the lowering of the relief on the dies probably had a lot to do with how they degraded over time.

I didn't think it was in full swing until mid to late 90's? LINK (http://www.varietyvista.com/Watershead%20Dates.htm)

Fixed the link.

[jallengomez]

I didn't think it was in full swing until mid to late 90's? LINK (http://http://www.varietyvista.com/W...ad%20Dates.htm)

I've never noticed an appreciable difference between the Philly and the Denver coins of that era when Philly was already using the single squeeze hubbing. Might be an interesting study though. I don't think it would matter though since that pertains to the hubbing of the dies and wouldn't have relevance to the deterioration of working dies.

[GrumpyEd]

Single squeeze was die making not coin striking, they may have improved the dies with different hardening or alloy, I think they were slowly tweaking things to improve it.

I always say and others don't agree is that the quality in mint set cents from 83 to the all of the 90s is way better and they did something different. It's not a 100% thing but it's not like the normal circulated bus strikes. In the normal bus strikes you need to search bags to find a few gems but in mint sets it's like 70%+ nice coins with tall rims and no polish lines and nice plating. I have mint set coins from those dates that are spotless PL with tall rims that I don't think you could match with anything found in rolls/bags.

I'm not sure why that is, maybe they used fresh dies? Maybe less beat up planchets? Something different when striking?

When people say they are the same, I think here's a test. Go find the best roll of cents that can be put together from those years. Put in one gem from a mint set. Anyone can easily pick that one out from a tube, it will have perfect shiny spotless tall rims and there are none like it in normal rolls or bags.

In the later years the TPGs claim they can tell the mint set coins because they are satin finish (even though there are satin ones in normal rolls/bags). But they never claim to tell the older mint set coins.

I could be right or wrong but if someone wants a top pop cent from those early years my advice is look in mint sets

[Petespockets55]

I wonder if there was a point where die maintenance and polishing (humans involved) was more costly than producing an adequate supply of dies from the get go. Produce an adequate supply of dies and let the machines run. Less man power and down time replacing reworked dies. Plus with more products to make with the State quarter, Prez dollars, etc, the presses needed to be running 24/7.

I personally think the mint did not use the dies as long as before. Probably started around the time of the plated zinc coins. Do we ever see modern LSC varieties with reverse or obverse dies changed out? (As happened in earlier years.)


EDIT: Yes to my question. I went through VV looking for changed out dies on varieties (1990 - 2018).

I only found 3!
A)1997p DDO-001, (FS 101)- 3 Reverse changes. When the obv was EMDS, LMDS, and LDS.
B)2004d DDR-004, ............ .. 1 Obverse change. When the rev was LDS.
C)2009p (FY) DDO-002 & DDR-006, ....... 2 Reverse changes. When the obv was MDS (DDR-009), LMDS

What I did find interesting was that VV only has 9 varieties with LDS examples attributed and 2 with LMDS. All the other varieties only go as far as MDS. Granted that most varieties don't garner a lot of interest so LDS examples may be out there.
Two notable exceptions are 1994p DDR-001 (FS 801) and 1997p DDO-001 (FS 101) have LDS examples.

Just food for thought!
ps. Viv, Jarden Zinc has provided all zinc planchets to the mint since the change over in 1982. I'm sure they have been tweeking their process and product right along with the mint.

[makecents]

Thanks Jody and Ed, not sure what I was thinking....

[makecents]

I wonder if there was a point where die maintenance and polishing (humans involved) was more costly than producing an adequate supply of dies from the get go. Produce an adequate supply of dies and let the machines run. Less man power and down time replacing reworked dies. Plus with more products to make with the State quarter, Prez dollars, etc, the presses needed to be running 24/7.

I personally think the mint did not use the dies as long as before. Probably started around the time of the plated zinc coins. Do we ever see modern LSC varieties with reverse or obverse dies changed out? (As happened in earlier years.)


EDIT: Yes to my question. I went through VV looking for changed out dies on varieties (1990 - 2018).

I only found 3!
A)1997p DDO-001, (FS 101)- 3 Reverse changes. When the obv was EMDS, LMDS, and LDS.
B)2004d DDR-004, ............ .. 1 Obverse change. When the rev was LDS.
C)2009p (FY) DDO-002 & DDR-006, ....... 2 Reverse changes. When the obv was MDS (DDR-009), LMDS

What I did find interesting was that VV only has 9 varieties with LDS examples attributed and 2 with LMDS. All the other varieties only go as far as MDS. Granted that most varieties don't garner a lot of interest so LDS examples may be out there.
Two notable exceptions are 1994p DDR-001 (FS 801) and 1997p DDO-001 (FS 101) have LDS examples.

Just food for thought!
ps. Viv, Jarden Zinc has provided all zinc planchets to the mint since the change over in 1982. I'm sure they have been tweeking their process and product right along with the mint.

Nice work Cliff and very plausible reasoning.

[VAB2013]

Wow! Thank you everybody for all of these comments! Now... I'm gonna go back and read them

Added: Really great info! Whenever Ed talks... I listen but if he were "live" I'd have to ask him several times to either slow down or please repeat that sentence! And thank you Jody and Jon for adding thoughts and knowledge!

I am really diggin' Cliff's research, and when I try to piece all of this together, what Cliff added made a light bulb go off! It does seem reasonable that while the Mint was working on tweaking so much during the beginning of the introduction of copper plated zinc cents that they may have done a man hour study and realized it was more cost effective to make more working dies instead of spending so much time trying to keep the old ones in production.

So, if this scenario is correct - that would mean that more working dies equal more chances of producing varieties - but less chance of seeing these varieties in later die states? Seems like that idea would line up with Cliff's research.

(please feel free to fix where I am wrong, or just throw some nice Lincolns at me )

[GrumpyEd]

I wonder if there was a point where die maintenance and polishing (humans involved) was more costly than producing an adequate supply of dies from the get go. Produce an adequate supply of dies and let the machines run. Less man power and down time replacing reworked dies. Plus with more products to make with the State quarter, Prez dollars, etc, the presses needed to be running 24/7.

I personally think the mint did not use the dies as long as before. Probably started around the time of the plated zinc coins. Do we ever see modern LSC varieties with reverse or obverse dies changed out? (As happened in earlier years.)


EDIT: Yes to my question. I went through VV looking for changed out dies on varieties (1990 - 2018).

I only found 3!
A)1997p DDO-001, (FS 101)- 3 Reverse changes. When the obv was EMDS, LMDS, and LDS.
B)2004d DDR-004, ............ .. 1 Obverse change. When the rev was LDS.
C)2009p (FY) DDO-002 & DDR-006, ....... 2 Reverse changes. When the obv was MDS (DDR-009), LMDS

What I did find interesting was that VV only has 9 varieties with LDS examples attributed and 2 with LMDS. All the other varieties only go as far as MDS. Granted that most varieties don't garner a lot of interest so LDS examples may be out there.
Two notable exceptions are 1994p DDR-001 (FS 801) and 1997p DDO-001 (FS 101) have LDS examples.

Just food for thought!
ps. Viv, Jarden Zinc has provided all zinc planchets to the mint since the change over in 1982. I'm sure they have been tweeking their process and product right along with the mint.

You could verify that because I remember that for modern years they tell how many dies were used someplace, somebody once posted about it. I think they were getting a lot of use out of the modern ones.

I'm surprised they re-pair them at all since the die life is only hours or a few days but apparently they still did in fairly modern years.

It might be something more general. If you work at a company that manufactures stuff they really focus on yield and cost.
When they start at low volume, yield/quality doesn't matter as much and if they need 8 things and yield is 80% it's ok, they make 10 and ship the 8 that work and toss 2 rejects.
When they ramp up to making a million of thing it's different, they don't want to make a million things including 200 thousand rejects to toss out. They do continuous improvement to get the yield higher.
Since now they make billions of cents each year they had a lot of incentive to get the yield high and cost low and dies are not cheap so they probably found ways of doing it better.

[jfines69]

If memory serves me correctly the mints went to an automated die polishing but I need to find the article for it... In the mean time here is a link to how Philly makes and polishes proof dies... At the bottom of the page are more links to West Point, Denver and some more Philly info!!!