What is S-L-M?

[coop]

What is S-L-M? Do you know what it is and didn’t know you were using it? It is used in sorting coins, identifying coins and cataloging coins. So what is it?
It is the means of telling one RPM from another. It is the means of identifying one doubled die from another. Got you attention yet? The S stands for seperation, the L stands for location and the M stand for markers.
So how is means of seperation used to sort coins? All mint marked coins before 1990 are re-punched. Yes. It takes more than one strike of the hammer on the punch to give the depth and width of the desired mintmark. When mintmarks punches don’t fall in the same punching area, a variety is made. Most of us are searchers for the miss-punched RPMs. Sometimes the mintmark is too close to the date numbers and would create a problem there, so they move the primary mintmark to another location. Because this punching area is small, some of the time these punches are located in a different locations of the primary mintmark. Sometimes this punch is rotated a little making marks on the corners of the upper or lower serifs or both of the primary mintmark. Sometimes the miss-punched area is above (North), or below (South), or before the mintmark to the left (West) or to the right, (East) of the primary mintmark position. Sometimes the direction is NE or SW or NW or SE of the primary mintmark position. When any of these miss-punches happen, they are called a seperation of the primary mintmark or called a RPM. The “S” of the formula is used to identify one RPM from another. The Seperation would account for 50% of the determination of the RPM.
The second determining factor is the “L” in this factor. Where is the mintmark Located? Some are above the bottom tail of the 9. Some are even, some lower. Sometimes they are closer to the second digit in the date; sometimes they are closer to the third digit of the date that ‘Seperation and Location,’ determines which die that the RPM your coin was struck from. The location figures in about 40% of the determining factor of which die it is from. All RPMs that have a seperation from the primary mintmark are cataloged with a number, as coming from a certain die. Not just from Seperation, but also Location. Some Separations of the RPM can be the same or close, but locations are usually different. Every once in a while the seperation may be the same and the locations may be the same. What then?
The third factor comes into place. The “M” stands for Markers. A marker can be a die scratch, crack, chip, break or a die gouge. But the middle three are a progression of die state. The die are scratched some by a cleaning process to remove die clash marks. Field scratches and gouges may and usually flatten with further usage of the die. So what was sharp on one coin may become a medium scratch and later a faded scratch. These scratches if they are not flattened into the die can serve as “finger prints” of a die. That means if the same die scratches are in the same area it could be visible on coins struck from that point on the same die. I had to add that word ‘could’ because of die clashes/cleanings/damage may be over each other and you might see a faded die scratch with another stronger one over top of the older die scratches and sometimes in different directions. Because of these factors of the die, coins scratches/gouges may help identify one RPM with a later die state. The extra die scratches/die cracks/die chips and die breaks help identify the aging of the die state of coins you may find. When a cleaning pattern is repeated on a die, the worker may use a similar patterns for removal of die clashes and be repeated from die making scratches in the similar direction. Other times they may be in different directions. Some die cracks/chips/breaks happen in the same areas over and over. Lets say a die crack on the 12th column. This may have little meaning as a description as most dies may break in that location because of design/contact from die clashes/weakness as die wear/ or cleaned to cover past die clashes. So it is not uncommon to see the same die cracks/breaks in the same areas over and over on different dies. But a very good marker would be a die break on a letter/number even though they progress to becoming worse, because they never heal. Another great one would be a die gouge. These are usually found on the outside quarter of the design. Sometimes they are located next to the rim. Other times in between letters which are also one of the best markers. Why? Because die gouges are usually so strong they never go away also especially next to letters/numbers. These act as a shield to not allow cleaning to remove them. Portions of faded die scratches are usually visible between letters/numbers and the flattening is prevented more in this area.
A common coin is one that has no RPM/doubled die on it, is usually used just for coinage. But varieties are saved/rescued from circulation are cataloged and sorted how? S-L-M. The correct way to use this is to use the steps in the correct order. So search for the (1) Seperation first. (2) Location second. (3) Markers last. If you go backwards, you may end up with egg on your face, as the seperation/location could be different than the coin you attributed to a die number. So taking it in the right progression, ensures a more correct attribution for your coin to RPM a certain die number. This also removes needless time wasted working backward and not have the attribution correct. Always remember that only about 10% of getting the coin matched to the right die is by markers. What can change on markers? Age. As the die that may make the RPM can change shape different than exact shape than the RPM was when it was in EDS (Early Die State). When considering die wear, one thing usually happens. The die enlarges from wear. The die is like a 3-D negative of the coin it shapes. So when a coin is struck, any imperfections/designs will be passed on to the coins made AFTER it. The die wears in the direction of making letters larger. This making spaces between letters/numbers, appear closer. RPMs get larger with age also. Some RPMs start out strong and sometimes fades as the die wears. Sometimes the die wears away fades or looses detail as fields wear away. Sometime RPMs get stronger with a later die state. The wearing of the die is noticed in the seperation/depth of the punching get deeper or make it fade into the field, as the field wears down the letters start to loose crispness in the area between the field and the letter/number. In MDS (Mid Die State) and LDS (Later Die States) you start to see die flow. This is the direction the fields’ wear and can become so strong that the field flattens and numbers/letters can snowdrift into each other. Eventually as die wear continues to wear the coin looses more and more detail.

Doubled dies are sorted by a similar process of identify them. First you check the seperation between the two hubbing and see direction of spread/degree of spread. These are referred to as classes. This usually is considered first, the (1) Seperation between the letters/numbers. Second is the (2) Location of mintmarks; which pertains to mint marked coins. The location of the mintmark, just like the case of the RPM is another determining factor of which doubled die was used to make your coin. On Philadelphia minted coins because of not having a mintmark (on Cents), you have to pay more attention to seperation/location of the direction the spread is in. Then finally (3) last the Markers that denote what that die life has experienced during it’s life. You may have a coin that is in an earlier die state than current information, and have none of the EDS, MDS or LDS markers. Or another possibility is that your Obverse die is matched with a different Reverse, or vise versa. The life of a die goes through many changes; so to say that a certain marker would be seen would only apply to coins struck after a certain even happened.

So what is S-L-M? It is the proper order to sort your varieties in. Starting with the (1) Seperation first. (2) Location considered second. And (3) finally by Markers as they may or may not be on your example you find. To go the opposite direction would be almost impossible to get the right die number. The markers can be just something that confirms you have die state of a die number, but not the determining factor. Happy hunting and identifying the coins you find, because there are coins out there that need your rescuing. Enjoy the search and identity as these both make this a hobby we love.

[Dick]

You had me confused for a second, until you became more explicit. Then The acronym "PUP" came to mind. I enjoyed your disertation,and will keep it handy. Does this imformation, get erased, deleted, or "just due to old age" get removed? There is so much information, and so important, that it would be a shame to get lost. I may start making hard copies, for my reference files. Is this legal? Many thanks for the info, which we all so very much appreciate!
Dick

[coop]

Dick:
There was one time where the inforation was lost, but restored with just a few post missing. So it should stay if things go right with the system.

[Dick]

Coop, you sure made my day! I love information, especially when it can be accessed, when needed. A reference Library is worth its' weight in gold. Dick