Die corrosion

[ray_parkhurst]

I think I've posted this long ago, after my 54-S roll fest search, but have come back to it for more discussion. The pictured coin has some odd surface characteristics. The coin is BU, but has what look like areas of corrosion. Those areas are incuse, not raised, so are not a product of a rusty die with missing surface metal. I found quite a few of these in a couple of rolls, and they span multiple dies. Looking at a few coins from the same die, the marks are "similar", and some are exactly the same (or at least similar enough that you would conclude they are from the die, not some other phenomenon), but there are slight differences that seem to be from a progression of whatever caused this phenomenon.

My hypothesis is that we are indeed seeing the product of a rusty die, but that the rust was still in place. Because rust on steel actually raises the surface slightly (since the rust is lower density than the steel), this produces an incuse area on the coin during striking. These rusty areas can wear away quickly, so there is a fast progression.

Now, is my hypothesis correct? Anyone else seen these sorts of corroded-looking coins? Note the reverse has similar characteristics.

IMG_0011_1.JPG

[VAB2013]

Very interesting Ray! Your reverse photo did not post but from looking at your obverse photo and reading your hypothesis, I have to agree.

[ray_parkhurst]

Here is the reverse:

IMG_0009_1.JPG

[makecents]

Ray, this may be way off base but I've seen Morgan dollars that looked very similar to this. It was said that it was from moisture being on the face of the die early in the day and only lasted for a few strikes. Granted, we are talking about different eras in time and would think the mint conditions were better when this was struck but just a thought. I tried to find an example but could not.

[ray_parkhurst]

Ray, this may be way off base but I've seen Morgan dollars that looked very similar to this. It was said that it was from moisture being on the face of the die early in the day and only lasted for a few strikes. Granted, we are talking about different eras in time and would think the mint conditions were better when this was struck but just a thought. I tried to find an example but could not.

This makes quite a bit of sense. Condensation on the dies overnight...surface rust not deep enough to cause lasting damage but enough to cause weird surface anomalies on the coin...surface rust gradually wears away or moves around as coins are struck.

This may also explain why grease is so often found on dies. Perhaps at the end of an evening shift, the dies were spread lightly with grease to keep water from condensing overnight?

I have a couple rolls of these. I should go through them and see how many dies are represented. There are at least 2 dies, and they came from the same group of coins, so for sure this is not limited to a single occurrence. Will be interesting to see how many dies show this, and if I can document a progression.

[WaterSport]

I agree its something other than a rusty die. I can not imagine any machinist allowing his/her work to get ruined. On top of this, the stories of using rusty dies I think comes from actual working dies being tossed on the ground once they are no longer needed (If you visit the Carson City Mint they have a great photo of this) and then a year or so later, the machinist needs an extra die for whatever reason and recuts and reuses a true rusted die, or they are used to make examples for profit past the year they were actually used and called restrikes.

It also looks to me that the highest points are coming out detailed enough and metal flow should be from the center outward thus the outer part towards the rims look the worst. JMHO.

WS

[ray_parkhurst]

I sorted the coins I have with this characteristic by die. I ended up with 9 different dies represented. It is clear that some of the coins from same die came from different rolls (toning is different) so I guess these were put together long ago by someone who thought they were interesting, then just sold as a standard roll. The coins are fairly ugly so would not attract attention from a non-specialist.

Here's the tally:
Dies 1 and 7: ~20 pcs each
Dies 2, 3, 4, 6, 8: ~10 pcs each
Die 5: ~5 pcs
Die 9: 3 pcs
Plus another 5 pcs still unsorted, some of which will be unique dies.

I will probably choose either die 1 or die 7 and shoot all the coins, then put them into some order (if an ordering exists). I'm not sure what I am going to find...

[mustbebob]

I have seen many examples of rusted/pitted dies over the years. 1954 is a particularly bad year for them. there were some in 1955 and 56 also so it might have been a handling/storage problem during these years. I do not however think some of these pitting problems were something that went away or got lighter as the strikes accumulated. I also don't think grease was used to coat the dies. The grease found on dies was from the mechanical workings of the machines while they were striking coins. I saw how some grease could actually splash onto/in to the striking chambers during both of the tours of the Philly Mint I was lucky enough to go on. My guess would be that pitted dies were the result of improper storage.

[ray_parkhurst]

Well, this phenomenon does not seem to have anything to do with rusted dies. See the attached images of 10 coins from a single die. I can't find an exact match to any particular pattern. Some of the coins are similar to each other, but others are very different, so no "sequence" makes sense. I have only imaged the obverses so far.

I'm leaning toward the "struck through condensation" hypothesis.

IMG_0028_1.JPGIMG_0027_1.JPGIMG_0026_1.JPGIMG_0025_1.JPGIMG_0024_1.JPGIMG_0023_1.JPGIMG_0022_1.JPGIMG_0020_1.JPGIMG_0019_1.JPGIMG_0019_1.JPGIMG_0018_1.JPG

[jallengomez]

Ray, I encounter that all the time with rolls from the 50s, and believe it to be struck through gunk for lack of a better word. Crusted grease on the dies that starts hardening. Similar, but not exactly the same as what Mike Diamond calls field-restricted, but with wheats from the 50s, it is not always restricted. On your reverse photo above, I can see its effects on the wheat ears, which is consistent with the ones I often find. For some reason, 54S and 55S in particular seem to be rife with these coins. Here's Mike's page on field-restricted struck throughs.

http://www.error-ref.com/field-restricted-struck-through-errors/

[ray_parkhurst]

Ray, I encounter that all the time with rolls from the 50s, and believe it to be struck through gunk for lack of a better word. Crusted grease on the dies that starts hardening. Similar, but not exactly the same as what Mike Diamond calls field-restricted, but with wheats from the 50s, it is not always restricted. On your reverse photo above, I can see its effects on the wheat ears, which is consistent with the ones I often find. For some reason, 54S and 55S in particular seem to be rife with these coins. Here's Mike's page on field-restricted struck throughs.

http://www.error-ref.com/field-restr...hrough-errors/

Thanks, good info. This looks a bit different, since it seems to move around quite a bit, though some parts don't move a lot. I'm certainly OK with thinking of it as struck through but the struck through grease coins I own seem different. Plus, I found so many of these, and from same die(s), that I thought it a bit unusual.

[jfines69]

At this moment in time my brain just fried Only thing I can think of off hand is orange peel http://www.error-ref.com/orange-peel-texture/ and maybe a rusted die http://www.error-ref.com/rusted-die/ I will need to do a little more research!!!

[ray_parkhurst]

I ended up posting over on another forum, and got lots of replies and discussion. The consensus was this is simply struck-through grease, which I can believe.

[willbrooks]

Just now seeing this for the first time, my freind. The struck-through-grease idea is utter nonsense, in my opinion. Don't fall into the fallacious pitfalls of argumentum ad populum, or argumentum ad vericundiam for that matter. The truth has nothing to do with what anybody says. Strive first for validity; truth is sometimes a byproduct.

[ray_parkhurst]

Just now seeing this for the first time, my freind. The struck-through-grease idea is utter nonsense, in my opinion. Don't fall into the fallacious pitfalls of argumentum ad populum, or argumentum ad vericundiam for that matter. The truth has nothing to do with what anybody says. Strive first for validity; truth is sometimes a byproduct.

Thanks Will. I am not a "go along" type of person, but I can be convinced by evidence and argument, given that my own experiences go with those. I think it comes down to these were either struck through grease, or through condensation/water. I'm pretty sure they are indeed struck-through, so that's not the issue. I am not sure how to tell the difference between ST grease or ST condensation. I presume there would be some difference in the shape of the ST areas, but I have (and nobody else seems to) have any examples of known ST condensation to show the differences. So at this point, I'm willing to accept ST grease until more evidence presents itself, in the scientific concept of a Theory.