How Are PL and DMPL Coins Made?

I have pondered this question for quite awhile so I figured I'd ask the CoinTalk community for a straight answer. When I first saw a DMPL (Deep Mirror Proof-Like) Morgan Dollar, I thought it was just a business strike struck with proof dies. I later found out that they are much more common than I had first thought. Yet, I still never found out how they were REALLY made. Any comments are appreciated!

Thanks in Advance ,
Brian

 

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I guess the easy answer is a freshly polished die was used. In reality it was more than that as not all years have DMPLs produced so there had to be more than a fresh die. The way dies were made also changed during the course of Morgan production so in 1900 DMPL and PL became more scarce and had a more brilliant look to them as opposed to the cameo look of the years before.

 

Interesting! That would make sense though. The die being freshly polished would create the same effect in the fields of the coin when struck. I never thought of that. Any more theorys, anyone?

-Brian

 

Actually, there are two types of DMPL's. As Vette mentioned, new dies that were polished before being put into service can produce DMPL coins. As a rule, about the first 500 produced can be DMPL, and the dies begin to deteriorate after that.

The other form of DMPL is produced from dies that have been removed from service and repolished. You can often tell the difference between these DMPL's and "original" DMPL's because you can see polishing lines in some areas of the fields.

Chris

 

What die polish?



I am looking for one of my images that was clashed and then the clash was polished off and it became DMPL again.

 

here is another fun one, die cracks around the letters yet DMPL and this coin has deep mirrors.

 

So would coins with a deeper cameo effect be the ones that would be in the category of the freshly polished, only 500 can be made dies? And ones with just the mirrored surfaces be the others mentioned? I am trying to understand how the cameo effect is created on an MS coin...

-Brian

 

Brian, cameo surfaces have nothing to do with the mirrored fields you see on DMPL's. Cameo is the "frost" that is imparted to the devices on a coin, and is usually associated with proof coins.

Chris

 

My 1878 7TF PCGS MS64 PL, PAF has deep mirrors, too. Can read letters out at 6". And she was tagged as a PL and not a DMPL. To me, she is a DMPL.

 

It has to be the same for both sides. Is yours?

Chris

 

I do believe so.

Read text that is 10point font at 6" away. That's the test, right?

 

6 inches wont necessarily get you a DMPL nowadays.

 

I haven't submitted any DMPL's to PCGS for quite a few years. What is their minimum requirement nowadays?

Chris

 

Yes, yes. Inquiring minds want to know.


I'm tempted to crack it out and send it to the NGC.

 

So Chris, is there a difference in value beteen an original DMPL & a DMPL created with repolished dies???

 

From my experience, repolished dies don't leave as much of a cameo effect. It's not hugely noticeable though.

 

I've got an 1880/79 small OVAM 4 that is from repolished dies. I posted it in a thread a couple days ago. I'm hoping to submit it and get it back as DMPL, but it may be only PL. I'm not too familiar with how strict the test is.

 

It's very strict. 3" minimum for PL, 6" minimum for DMPL.

 

When the dies are hardened they are heated then quickly quenched. This leaves them with slightly roughened oxidized surface. It is this oxidation (and a basining of the dies) that the initial polishing is to remove. But the die lap does not get down into the design features so they still have a slightly roughened surface. When the first coins are struck the polished fields supply the mirror fields to the coin while the rough surfaces in the devices makes a slightly rough surface on the devices of the coin that scatter light in all different directions. This makes them appear white and frosty compared to the fileds which then to reflect the light all in one direction (and typically away from your eyes). That provides the cameo contrast.

As more coins are struck the movement of the planchet metal smooths those rough surfaces reducing the light scattering ability of the devices on the struck coins. As more coins are struck the contrast continues reducing from the smoothing in the devices and roughening and flowlining of the fields. You go from DCPL to CamPL to PL to just a frosty Unc. If at some point the dies are repolished the devices may again show some contrast compared to the field, but not as much as when the die was new and possibly very little at all. If the devices are well smoothed it would be possible to have a deep mirror prooflike with very little or even no cameo contrast.

 

That sounds more like NGC, I think PCGS may be a little tougher.

Not sure how you could tell the VAM 4 is repolished. Normally you would see a sequence, i.e., some coins struck, then a clash, the repolishing and some clash evidence left. The VAM 4 I dont think has any clashing or real need to be repolished. The POP dont suggest that there are that many out there.