How do you pin down a RPM

Rhubarb · Senior Member

I have noticed alot of the coin's that I'm searching thru are very Similar but not quite the same as the coin's listed on the RPM picture's. Do the coin's have to be exactly the same? Can they be close to or similar to the picture's. I ask this question because I don't won't to mis-identify a coin. Has anyone else had this experience or is it just me being overly cautious.

Rhubarb

coop · Expert Member

Rhubarb: The difference between a variety and an error is this. A variety is made into the die whether it be a RPM (Re-Punched Mintmark) DD (Double Die obverse or reverse) OM (Over Mintmark) OD Over Date. All of these are a die issues. The die was doubled over letters/numbers details. All these are called varieties as they are exactly the same whether they made one coin or 500,000. All will have the exact seperation of the Letters/numbers/details. The RPMs will have the same Seperation/Location of the mintmark. The markers may be different and wear may change some sharpness of details. The shape of some RPMs may be stronger in EDS die states and weaker in LDS die states. Some RPMs can be weaker in EDS and others stronger in LDS. So it depends on the variety on which way this is. IE: The 1956D-1OM-001 the miss-placed S will be weaker in LDS examples and stronger in EDS examples. On the 1956D-1OM-002 The opposite is true. The S is barely seen is EDS, while the LDS examples show a full S pattern. So depending on the variety, the RPM/DD is stronger/clearer/weaker in different die states. But one thing is always present. On RPMs the location is always the same place from the date. Exactly so you can do an overlay and see the location. In order to come from the same die the location must be in the same place. When we number dies, the number designates the die that made the coin. So when we say 1960D-1MM-001: that die made all of the examples we find and love to collect. So to with all the rest of the RPMs/double dies. They all were made from the same die. So when we are searching and find an anomoly, we search for the number of that die. Wear does have an effect on some DD's as some types of doubling can only be found on EDS examples. Some are seen on EDS and MDS examples. But unless the seperation is very strong, the doubling disappears more and more on LDS and VLDS examples. Tou may of had a certain double die in your hands and because of wear of the die, it may not be seen if it is on the outside edge of the coin. I've found an example of that. On a memorial Cent I found where the outside doubling had been covered with heavy die flow, but on the EPU near the center, it was still visible. But once the doubling disappears the coin is just a regular coin. This Seperation and Location will always happen to the coins because of the die. That is why they are called varieties.
An error is something that can happen once or several times during certain conditions. If a planchet has a clip. The coin that came from that roll with a clipped planchet will have that error. If machinery is loose, it will create mechanical/machine doubling. This is not the same on every coin. Can be in different directions, major or minorly affecting the coins during that machine is loose. It is a machine issue not a die issue. If a coin gets stuck on a die and creates one or two brockage coins. Again it affect a few coins, the die is not doulbled, just the coins are affected. When coins are found without plating, without the setup, with grease filling the die, with string/wire/cloth in the way, with die breaks/cracks/cuds: these are coin issues, not a doubled issue of the die. Just coins are affected.
So that is why if you find a coin with different seperation as one listed on the site, or a coin with different locations as those listed on the site, the coin could not have came from that die. So Remember the formula when trying to catalog your coins. Seperation of the RPM doubled die is considered first. On RPMs/doubled eyelids locations matter. Lets say you found the seperation matches the site, we do an overlay of one of the site and it is a match, but no markers match. Looking at the RPM again you may note one separation is stronger than the other. They are from different dies. They have to be exact in order for them to be from the same dies. Again markers are just used to determine die states of the coins considered. You may have a coin made before/after/between the images posted. They just don't take a die and declare it EDS examples at the mint. Die states are just aging. So don't be surprised if your coin doesn't match exactly for markers. But the die scratches new/medium/faded could last for an extented period, or just for a short time. Depending on what happens to the die. Die clashes put the die through the wringer. So cracks/cleaning/aging are just what they go through till they are retired. Some clashes may cover one that just happened or several thousands of coin may be made between them. Each time the die experiences die damage/cleanings disfigurment happens to it. So remember: Your coins could fall anywhere in the life of a die. It takes a trained eye to figure out when it occured, or some are just happy to find an example in any die state. Hope this helps.

eagames · Expert Member

The markers can be different, maybe your coin is the same die but before the markers were on the die or after they polished them away.

The position and RPM must be exactly the same. If you can do overlays you can disprove many by them being not in the right position. Being close but one differance like position rules them out. A given RPM number means a specific die.

I start by looking at the MM doubling. Just noting the direction of shift narrows it down to less choices. Then compare position and look for markers. I can match many but I do have a few in my ??? pile. They're either unlisted ones or I just don't see any marker to be sure of them. Some years are full of RPMs, if there's 100+ it's tough. As your skills and setup improve you can go back to the ??? pile and solve more of them. Sometimes if you have good pics on the site others can help ID them.

Rhubarb · Senior Member

"WOW" coop and eagames. That's a mouthfull. Your explanation was clear and precise. I now have to figure out how to do a overlay. Also what is a EPU? Now I really have my work cut out for me.

Thank's

Rhubarb

coop · Expert Member

If you have Photoshop, check out the Photography section for this subject.

Rhubarb · Senior Member

I only have Kodak. I will have to purchase Photoshop.

Thank's Coop

eagames · Expert Member

EPU = E PLURIBUS UNUM the revese motto

Sometimes you can rule them out by position without an overlay. I start by looking at how close to the date it should be (vertical position) then by looking how it lines up with numbers (horizontal position). If it is way different you will see it and rule some RPM out. If it's closer it needs an overlay.

ldarrellc · Senior Member

Coop,

Thats the bet one of Rodney yet. But just a question do you find them to be true in real life. Twisted Evil

lol

Steven · Expert Member

Rhubarb,
If you have some photos you need worked with photoshop I'd be glad to help til you get the program. PM or e-mail me and let me know if there is something I might be able to help with. I'll do what I can.
Steven

Rhubarb · Senior Member

Stephen,

You bet I will. Thank's

Rhubarb

Earwig · Veteran Member

Im workin on a tough 1 now i think i finally found 60d rpm 11 and thanks to brian ribar who sent me a issue of the hub that had a great article on it i think i will find some. Im going through 2 rolls of rpms that have at least 2 of the 3 markers and doin overlays so far none but im sure i got them and by the time im done i might be able to do a overlay with no problems. Also i was told by a friend they were found in fed rolls of cleveland that had 60d rpm 7 in them

Eric

coop · Expert Member

Eric: Keep us posted and please post an image of the RPM. The RPM book is SO vague. I've questioned if that die really exists. Looks more like machine damage to me. Of couse I would be interested in one if you have extras.

Earwig · Veteran Member

Will do there is a great article in the may/june hub 1999 detailing 2 dif die states if i could just get overlaying and resizing down it would make it easier but im gunna keep pluggin away and will post a pic if i find it

Eric

coop · Expert Member

Eric: If you have photoshop, there is advise in the photography section that might help you there. If you have another program, you might find something there that will correspond to your program??