Really strong over-polished die

JRocco

Think they got a little carried away when they polished this die? Great color also.

DorkGirl

It looks like they took a grinder to it Very cool, thanks for sharing.

Purple73

WOW! You keep posting stuff like this Imma call you Die Polish Dude. Very cool find! I actually would like to have that one....That is way cool.

errormaven

<< <i>Think they got a little carried away when they polished this die? Great color also. >>



I think this is accidental abrasion caused by a machine part scraping against the die face. Perhaps a feeder finger. The die scrapes are relatively wide and are all going in a single direction, while ordinary die scratches are much finer and travel in multiple directions. I have seen other many other examples of accidental abrasion like this, but this one is particularly severe. It's an area in need of much more research (I'm working on it).

JRocco

Thanks again Mike for your observations. If you would like to see this coin in hand just shoot me a PM and I will send it your way to look at.

errormaven

<< <i>Thanks again Mike for your observations. If you would like to see this coin in hand just shoot me a PM and I will send it your way to look at. >>



Your excellent photos suffice. I will capture the images and store them in my computer. I hope you will grant me permission to use them in my article (which is still in the research phase).

Unidirectional die scrapes are fairly common on the reverse of recent Lincoln cents (1990 and later). I have found them on the obverse of quarters dating 1996 and later. Some Arkansas quarters that Fred Weinberg has show unidirectional die scrapes on BOTH faces, in perfect alignment They can be quite severe, wiping out low-lying areas of the design.

Here are some unidirectional die scrapes on a New Jersey quarter:Text

errormaven

Here's some really severe intentional die abrasion ("die polishing") that puts the "three-legged" buffalo nickel to shame:

Link

JRocco

Yes Mike you have my permission to use these pics. Here are a few more I hope will help. If you need any area in particular just let me know.

mgoodm3

That's very cool.

mgoodm3

Here's my best example of excessive die polishing. Found it in circulation a while back. the L in liberty is almost gone and IN GOD is getting pretty weak.

airplanenut

Here's my die polished friend...




Notice how the die polish funnels the lustre:

Crackout

This may or may not fall under the category of "unidirectional die scrape", but I thought I'd share - found in change the middle of last year:

Smitty79

Die polish is indeed cool.

jonesy

Interesting.

errormaven

<< <i>This may or may not fall under the category of "unidirectional die scrape", but I thought I'd share - found in change the middle of last year: >>



The 2004-D cent does not show die scrapes or "die polish". Instead, it was struck through a smooth viscous fluid, such as grease or oil. The streaks you see on both faces are the original streaks that are almost always present on an unstruck copper-plated zinc cent planchet. I forget what causes those streaks (any help out there?).

In any case, the smooth viscous fluid has no texture of its own. When it is struck into the coin it preserves the original surface texture of the planchet, streaks and all. At the same time it clogs recesses in the die face, causing weakness in some design elements.

One can occasionally find off-center coins struck through this fluid, and the streaks on the unstruck part of the coin line up perfectly with the streaks on the struck portion of the coin.

errormaven

<< <i>Here's my best example of excessive die polishing. Found it in circulation a while back. the L in liberty is almost gone and IN GOD is getting pretty weak. >>



A familiar sight. Among cents, the years 1972 and 1974 produced a bumper crop of heavily abraded obverses. I have some from those years that are far worse than this.

Conder101

<< <i>The streaks you see on both faces are the original streaks that are almost always present on an unstruck copper-plated zinc cent planchet. I forget what causes those streaks (any help out there?). >>


Think of them as linear "flowlines" created by the stretching of the metal as the ingot is rolled. In severe cases these streaks can be very heavy if the rollers are becoming worn and developing flowlines on their surfaces as well. (Ordinarly the roller have polished surfaces to minimize the streaks on the strip and resulting planchets.)

Myqqy

This is an excellent educational thread....

errormaven

<< <i>

<< <i>The streaks you see on both faces are the original streaks that are almost always present on an unstruck copper-plated zinc cent planchet. I forget what causes those streaks (any help out there?). >>


Think of them as linear "flowlines" created by the stretching of the metal as the ingot is rolled. In severe cases these streaks can be very heavy if the rollers are becoming worn and developing flowlines on their surfaces as well. (Ordinarly the roller have polished surfaces to minimize the streaks on the strip and resulting planchets.) >>



So you're saying that the "flowlines" on the zinc strip persist even after the planchet is plated? It is true that the unplated zinc planchets and blanks seem to have the same streaks as the plated planchet. But it is somewhat counterintuitive to accept that the streaks persist on the plated coin with no loss of clarity.

Another explanation I think I heard is that the streaks on the unplated blanks and planchets are caused by "scrapers" that remove surface oxidation from the strip after rolling is completed. Of course, here again, one must wonder why the streaks persist despite the copper plating, which is deposited after the planchets are upset.

indianabyron

Well anyways they are all cool looking.

Byron

Conder101

The copper plating on the cents is only .0002 inches thick and it is thin enough to allow the lines to remain visible.

errormaven

<< <i>The copper plating on the cents is only .0002 inches thick and it is thin enough to allow the lines to remain visible. >>



I assume you are correct, as I can't imagine any other explanation. The proof of the pudding, I guess, would be to find a partially plated cent that is struck off-center and where the off-center strike overlaps the plated and unplated areas. Then one could determine whether the streaks on the uplated portion line up, and are continuous with, the streaks on the plated portion.

If anyone out there has such a natural experiment, please let me know.

errormaven

<< <i>

<< <i>The copper plating on the cents is only .0002 inches thick and it is thin enough to allow the lines to remain visible. >>



I assume you are correct, as I can't imagine any other explanation. The proof of the pudding, I guess, would be to find a partially plated cent that is struck off-center and where the off-center strike overlaps the plated and unplated areas. Then one could determine whether the streaks on the uplated portion line up, and are continuous with, the streaks on the plated portion.

If anyone out there has such a natural experiment, please let me know. >>



I wasn't thinking straight. All that would be required would be a partially plated, unstruck planchet.

A useful surrogate would be a partially plated cent that was also struck through oil or a similar smooth, viscous fluid that preserves the original texture of the planchet. Then one could compare the orientation of the streaks in the unplated areas not struck through oil, the unplated areas struck through oil, and the plated areas struck through oil. If the streaks in the plated and unplated areas match up in direction, fineness, and density, and especially if they can be followed unbroken from unplated to plated areas, then the hypothesis that they are indeed the same is confirmed. I will have to go through my stockpile of partially plated cents to see if I have any of these combo errors.