What You Need To Know about: Strike

Discussion in 'US Coins Forum' started by physics-fan3.14, Apr 12, 2010.

  1. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    What You Need To Know about Strike

    By Jason Poe


    If you’ve hung around these boards for any length of time, and if you’ve even remotely paid any attention at all to what I say, then you probably know that strike is a big deal for me. A well struck coin is a beautiful thing, with full, bold details bringing out every strand of hair of feather that the engraver intended. Indeed, strike quality is one of the basic aspects of a coin which is used to assign a grade – and yet it is so often overlooked. The five basic aspects of grading: luster, strike, wear, bagmarks, and eye appeal, all combine to produce the grade of the coin. For more on the first of those, Luster, see my article here: What You Need to Know About Luster

    There are three very different things which can happen on a coin, but which can often confuse observers. These three things generally control the level of detail on a coin, and often produce somewhat similar appearances, but they are very different and should be considered differently when grading a coin. The first of these is wear on the die, also known as a late die state. The second is wear on the coin from circulation. Surface preservation and the subtleties thereof are beyond the scope of this discussion (but may be forthcoming in a future article). Finally, strike also influences the amount of detail on a coin.

    [​IMG]
    (An incredibly well struck Franklin half dollar – don’t worry, I’ll show plenty of different kinds of coins in this article)

    Creating a Weak Strike
    So, lets quickly review how a coin is made. A planchet enters the coining chamber, and rests on the anvil die. The hammer die comes down with a certain amount of pressure, and strikes the coin. The metal of the planchet cold flows up into the recesses of the die, and the coin is ejected from the chamber. The amount of detail that is transferred from the die to the coin depends on numerous variables – the amount of pressure used to strike the coin, the type of metal the coin is made of, the amount of detail on the die, the time taken to strike the coin, the spacing of the dies, and others. All of these variables must come together exactly right to produce a well struck coin.

    The design of a coin is important in producing a well struck coin, especially the balance between the two sides. Having a high relief element on the obverse directly opposite a high relief device on the reverse will generally result in a weak strike. The metal will not properly flow into the devices. Type I gold dollars had this problem, which was somewhat ameliorated by the redesign to Type II. Many of the coins which have strike designations (discussed below) suffer from this problem – the key area is a high point directly opposite the high point of the design on the opposite side.

    Metals and planchet shapes are also very important. Nickel is a very hard metal, and thus is very difficult to strike properly. The mint had a hard time with die life in the early days of striking nickel coinage. Copper is a much softer metal, and thus easier to strike (note that no TPG strike designations are on copper coins). Silver is softer yet, and of course, gold is the softest of all commonly used coinage metals. Thus, finding a well struck nickel coin is going to be more difficult than a well struck silver coin, all other things being equal. How long and to what degree the planchets are annealed is also important. Annealing is a process metallurgists use to soften metals by heating them. It’s a very interesting process and used in numerous places throughout the mint, but a full discussion of it will have to wait for another time. Suffice it to say that improperly annealed planchets are the biggest reason that New Orleans mint Morgans are often poorly struck.

    [​IMG]
    (A well struck Morgan Dollar, and a well struck Mercury Dime)

    The actual shape of the planchet entering the coining chamber plays an important part in determining the final strike. A planchet has a measurably smaller diameter and larger thickness than the final product, to allow metal to flow properly into the die. As the dies come together, the pressure of striking causes the metal to flow, compressing the planchet and causing it to flatten out – just like pressing a burger with a spatula will cause it to flatten. It is this flowing process that also creates luster. Insufficient metal at the edge of the planchet will cause peripheral lettering to be weakly struck, because there is not enough metal to fill the die at that point. I don’t want to overwhelm the reader, but the shape of the rim raised in the upset mill, also known as the “planchet upset angle,” also plays an important role in determining metal flow.

    The third major factor in producing a strong strike is the actual coining process. Note in the list above that several of the things I mentioned all come together in an instant – pressure of the strike, the time taken for the strike, and the spacing of the dies. The pressure of striking is different for each series and denomination, but pressures somewhere between 50 and 200 tons per square inch are used on modern presses. A phenomenon known as a Die Adjustment Strike occurs when the operator is first setting this pressure – he has to adjust the operating press in increments, striking only a coin or two at a time until the correct pressure is found. If the pressure is set too low, the product will be a weakly struck coin. Once the operator has found the proper pressure, he locks the “ram pressure locking device” in place – essentially a large bolt. If the bolt isn’t tightened properly, the vibrations of an operating press may cause the bolt to loosen – adjusting the pressure and causing weak strikes. At other times, a slightly lower striking pressure is a conscious decision of the mint. Lower pressures translate to longer die lives, and cheaper operations – one of the leading causes of weakly struck coins from the San Francisco mint during the 1940’s and ‘50’s.

    The spacing of the dies during striking is of comparable importance. The mint operator changes this spacing, and improperly set dies will cause a weak strike. Similar to the pressure, more widely spaced dies will result in a longer die life. More closely spaced dies will result in a higher pressure of strike, and longer contact with the planchet. Further, the dies must be level and parallel to each other (known, oddly enough, as die leveling). This is also adjusted by the press operator, and misaligned dies will produce a weak strike, or the error known as Vertically Misaligned Die if severe enough.

    [​IMG]
    (Die adjustment strike on a South Carolina State Quarter)

    Certain mints in certain eras were better at gettings things right. Two of the classic examples of generally poor strikes are New Orleans Morgans, and San Francisco mint coins of the ‘40s and ‘50s. There are a dozen different reasons why a strike might be poor, but each reason will leave telltale signs. The New Orleans mint improperly annealed the planchets during some eras, causing them to be harder. Harder planchets make it more difficult for the metal to flow properly, and thus the details will not strike up correctly. The San Francisco mint used too little pressure, too widely spaced dies, and used dies for too long.

    Knowing the characteristics of strike for your chosen series will help you choose only the best coins for your collection. Each series is different, each mint is different, even each date is different – only through careful study will you learn the vagaries of strike for your series. For example, as you all know, I have studied the Franklin extensively. The 1948D and 1952D are two of the best struck issues – the 1952S, 1953S, and 1962 are some of the worst struck.

    From the Theoretical to the Practical
    Now, as all good scientists should, let’s progress from the theoretical to the practical side of things. How exactly do you recognize a weak strike, and how do you differentiate between that, worn dies, and wear?

    The easiest to tell apart is a worn die. As a die strikes coins, the highest parts of the die come in contact with the planchet first. The low regions of a design are struck first, and then the metal flows up into the lower regions of a die (which correspond to the higher parts of a coin). Thus, just like a coin in circulation loses detail on the highest points first, the die likewise begins wear on its most vulnerable areas. Always remember, the high points of the die are the lowest points of a coin! Die wear will affect all parts of the coin, but a weak strike will affect the higher regions more strongly. If you are trying to decide if a coin is weakly struck or from worn dies, look at the low points, or the hidden areas of a design. If they are clear, crisp, and sharp, you have a weak strike. If the low points are soft and indistinct, you probably have a worn die. Everything you need to know about die states, and the appearance of die states on a struck coin, can be found here: Die States.

    A differentiation must be made between a good strike and full details for a series. On many series, due to the deterioration of the master die, a good strike does not imply full details – it only implies good details for the date and issue. The 1948 Franklin, being the first in the series, almost always comes with full details, even with a weaker strike, but the vagaries and variabilities of striking still remain. Thus, a coin not fully struck will exhibit far more details than its counterpart from ten years later, but will be somewhat below its sister 1948 coins. This is why a very large percentage of 1948 Franklins are FBL, because even with a weaker strike, the bell line detail is still present. As time progressed, the details began to wear off the master – even brand new dies lacked the finer details of that first year. This is a fate shared by almost every series. The first year that a master was used, the details are sharp and crisp. As time goes on, the details will become softer, until they get to the point where a new master was made.

    A common indicator of a weaker strike is called “high point pitting.” When the force on the planchet is insufficient to cause metal to flow into all the deepest recesses of the die, the high points of the coin appear shiny or uneven. The places to look for this are, for example, towards the bottom of the bell, and on Franklin’s cheek and jawbone. This is an indicator of a weaker strike, and will tend to limit the grade and any FBL designation. Severe high point pitting will limit the grade to 64, but minor pitting is allowable on a 65. Avoiding pitting is difficult because it is so common. When the metal flows into a die, it is the high points of the design which are last to be filled – and thus the high points are the most subject to high point pitting. In the picture below, note the myriad ticks and marks on the cheek and jawbone of Franklin, and how in the picture it appears to be darker. In hand, with the light on it, these darker areas are actually quite shiny. This is a rather extreme example, showing high point pitting at the base of his bust as well. This is a 1953S – notorious as the most weakly struck in the Franklin series – and the coin received a grade of 65.

    [​IMG]
    (A Franklin with extensive high point pitting, and a Walker with softness on the high points – especially her hand)

    Telling this high point pitting apart from wear may seem difficult, but with practice and experience, as in all things, it is possible. The key is their different appearances. High point pitting due to a weak strike will appear as a region of tick marks on the high points, but generally will still be bright and shiny. The tick marks are handling marks from before the planchet was struck – the contact with the die due to striking pressure smooths out any marks or ticks that a planchet may have received during handling. Wear, however, will generally appear smooth. It will generally appear first as a discoloration on the high points. As more wear occurs, the highest points will begin to rub off, leading to a flattening.

    The Capped Bust Half shown below is an excellent coin to use in a discussion of wear versus strike – because it displays both. The coin itself is graded XF-45, although many feel it is an undergraded AU. There is only light wear on the highest points, which you can see as a different color in these pictures. Notice how her neck is one color of silver, but the highest point of her cheek is lighter. Notice also how the high points of the curls of her hair are a lighter grey. This is due to wear. Now, look at the drapery around her bosom. The amount of detail missing here is incongruous with the rest of the coin – so we look at the discoloration of the high points as a clue. The drapery is mostly missing due to a weak strike, which is common in this area on these coins. This is where experience and study play a key role in trying to determine if your coin has weak strike or wear.

    [​IMG]
    (A coin with wear on the highest points. Note the discoloration on her cheek and hair. Notice also that the drapery at her bosom is weak due to a weak strike. )

    So What Does This All Mean to Me?

    Strike should play an important factor in the grade of a coin. The basic aspects of grade are strike, luster, technical preservation, and eye appeal. Technical preservation, or how many marks and dings the coin has, is easy to assess. Luster is similarly easy to assess, although considerably more subjective – what I think is beautiful luster deserving a high grade, you may think is merely average. Eye appeal, of course, is the most subjective of all. The gorgeous rainbow crescents on that Battle Creek Morgan may appeal to me strongly so I will bump the grade up a point, but you may view it as damage and downgrade it a point. Strike, I believe, is one of the harder aspects of grading, and is thus often overlooked.

    A coin grading 65 should have a full strike, if not exceptional. Learning to tell what a full strike looks like simply comes through practice and experience, and viewing hundreds of coins. Alas, many if not most collectors do not have this practice and experience. If the strike is less than full, it should be downgraded. A coin should be well struck to receive a grade higher than 65. Unfortunately, even the TPG’s seem to place less emphasis on strike than they should. This leads us to the final area of strike we will discuss today: the ever-contentious strike designations.

    Knowing the scarcity of well struck coins, a collector who values strike is willing to pay a premium for a coin well struck. Certain series are known for their weak strikes in particular areas of the coin, and thus a coin which shows all the detail in that area will garner a premium. The TPGs recognize several strike designations: Standing Liberty quarters have a Full Head designation (abbreviated FH), Jefferson nickels have Full Steps (FS), Mercury Dimes have Full Split Bands (FSB or FB), Roosevelt Dimes have Full Torch (FT), and Franklin half dollars have Full Bell Lines (FBL). Other coins which are sometimes sought specifically for their strike, but which are not designated by TPGs, are Walking Liberty Halves with full thumb (or full skirt lines), and Susan B. Anthony Dollars with full talons. I am not going to go into detail on each of these designations, as they have been covered elsewhere.

    [​IMG]
    (Picture of well struck WLH – note the full thumb and knuckles, full skirt lines, and overall crispness of the design. )

    The theory behind these strike designations is that these are usually the highest points of a coin, and are the most common areas to be weakly struck. Often, the high point of one side is directly opposite the high point of another, so these details require the fullest strikes to be completely impressed. If this area is fully detailed, then the coin is probably well struck. While this sounds good, in practice it is often quite different – a Walker with a full thumb may have poor detail on the eagle’s feathers, or a Franklin with full bell lines may lack detail in Franklin’s hair. The strike of a coin must be taken as a whole to be properly evaluated. Further adding to the complications, it seems like every collector (and more importantly, every TPG), has their own definitions for each of these designations. The confusion detracts from the coins.

    Whether you agree with the strike designations or not, there is no denying that they generally bring large premiums over their non-designated counterparts. A 1953S Franklin graded 65FBL may bring upwards of $20k, whereas a regular (softly struck) 1953S such as the one above will be lucky to break $100. This is an extreme example of one of the scarcest strike rarities, but even commonly well struck coins will bring premiums. Other strike rarities to be aware of include the 1953 Jefferson, 1945 Mercury, 1926D Standing Liberty, and 1941S Walking Liberty. Well struck examples of these coins all receive astounding premiums above their normal counterparts.

    Besides the series which are collected specifically by strike, be on the lookout for well struck examples of whichever series you choose to collect. A strong strike brings out all the details of a coin, and produces a much more beautiful coin. It may take a while to find an eye appealing coin with a good strike, strong luster, and all the merits you seek – but it will be worth it in the end.

    Jason Poe

    [​IMG]
    (I leave you with a trio of incredibly well struck Classic American coins.)
     
    Hambone1946 and Dynoking like this.
  2. Avatar

    Guest User Guest



    to hide this ad.
  3. Coinman1974

    Coinman1974 Research, Research, Research

    Very Impressive article! :high5:

    This is something I have been thinking of getting more into as I have collected coins. The Well Struck Coins.

    Thank you for the time you have put into this.

    Regards,
    Stan
     
  4. Duke Kavanaugh

    Duke Kavanaugh The Big Coin Hunter

    Great info!!
    Thanks for taking the time.
    I'm still having to work on that high point pitting but I'll get there.
     
  5. majorbigtime

    majorbigtime New Member

    Good discussion.

    How do you answer the age-old question: Should strike affect grade?
     
  6. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    Strike absolutely affects grade. I talk about it in the article, under the heading "So what does all this mean to me?"
     
  7. GDJMSP

    GDJMSP Numismatist Moderator

    Jason I have to disagree with you about a couple of things. This high point pitting that you mention, it isn't due to a weak strike. And it does not appear dark in the pictures because it was a weak strike, it appears dark because the coin has come into contact with something or rubbed against something and the frost is gone.

    And the depressions or tick marks that you describe as high point pitting, if they appear to be shiny as you say, a lighter color than the rest of the coin, then they are most definitely not due to a weak strike - they are contact marks. And they appear shiny because the metal exposed underneath has not toned like the rest of the metal.

    Only if the bottom of these depressions are a slightly darker color, not toned mind you but darker, than the rest of the coin can they be due to a weak strike.



    And this is not true - "A coin grading 65 should have a full strike, if not exceptional."

    While some coins that grade 65 will have a full strike, a full strike is not required for a coin to grade 65. In fact, there are a great many weakly struck coins that grade 65 and higher.

    Of course it depends upon which set of grading standards you adhere to, but even the ANA standards which are much stricter than the TPG standards do not require a full strike for a grade of 65.
     
    joecoincollect likes this.
  8. GDJMSP

    GDJMSP Numismatist Moderator

    While I agree with you, quality of strike has very little to do with grading as far as the TPGs are concerned. This is plainly evidenced by all of the weakly struck coins they grade 66, 67 and higher.
     
  9. majorbigtime

    majorbigtime New Member

    In theory, strike should not affect grade.

    Yogi Berra said, "in theory, there is no difference between theory and practice. In practice, there is".

    The same can be said about strike and grading.
     
  10. physics-fan3.14

    physics-fan3.14 You got any more of them.... prooflikes?

    Doug, the issue of strike affecting grade is subjective - I'll give you that.

    However, the high point pitting issue is well known. I got the term originally from Tomaska. You will see it quite often on weakly struck Franklins, as the one I have shown. Take a look at weakly struck Walkers - the high point down the center of the obverse where her hand is, down her thigh, will often display fine tick marks where the strike is incomplete. The coloration appears different because the metal did not flow up into the die, and has no or different luster, compared to the rest of the coin. It has nothing to do with coming into contact with something.
     
  11. GDJMSP

    GDJMSP Numismatist Moderator

    We shall have to agree to disagree on that one.
     
  12. Apocalypse Cow

    Apocalypse Cow Junior Member

    I learned quite a bit from that article as well as your luster piece Jason. Thanks for sharing.
     
  13. schatzy

    schatzy ~Roosie Fanatic~

    Great Article Jason!!

    Here is a my 1983-P!!
    You will simply never, ever find a sharply struck 1983-P, and that means they will always have those trivial little chicken-scratch marks all over the portrait. Some may think this 1983 is over-graded but if you ever studied the 1983 quarters you will find that this is a very nice example.
    [​IMG]
     
    Anthony Mazza likes this.
  14. mpcusa

    mpcusa "Official C.T. TROLL SWEEPER"


    Great info !! Thanks
     
  15. ksparrow

    ksparrow Coin Hoarder Supporter

    Very well written and illustrated, I learned a few new things tonight-- thanks!
     
  16. CheetahCats

    CheetahCats Colonial & Early American

    Thanks for posting. It's obvious you spent considerable time preparing this :)

    As with research nowadays freely floating around the net that is sometimes plagiarized and someone else taking credit, I personally think you should have 'baked' this into a PDF, declared copyright, and then share it.

    Nice job and great info!
     
  17. dimeguy

    dimeguy Dime Enthusiast

    Thank you so much for posting such a great well-written article with great illistrations. I am sure it must have taken quite a bit of time, but personally I'm thankful for it as I've learned quite a bit. Thanks again. Now off to read the luster article.
     
  18. BR549

    BR549 Junior Member

    ~whew~ I got through it, now I'm going to read just a few parts at a time to impregnate my brain.
     
  19. GDJMSP

    GDJMSP Numismatist Moderator

    When you do, read it here - http://www.cointalk.com/t58435/ . There is much additional and very important information that is not contained in Jason's original post on the NGC board.
     
  20. raider34

    raider34 Active Member

    Very well thought out, great thread Jason :thumb:.
     
  21. DoK U Mint

    DoK U Mint In Odd we Trust

    Wonderful

    ThanX for your work.:high5:
     
Draft saved Draft deleted

Share This Page