What Caused these spiral marks on a coin?

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Windycity
Windycity Posts: 3,603 ✭✭✭✭✭
in U.S. Coin Forum
1990-D Kennedy - Obverse shows light spiral marks through most of the coin but particularly noticeable in right field and across back hair of Kennedy. What causes such marks?

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<a target=new class=ftalternatingbarlinklarge href="http://www.mullencoins.com">Mullen Coins Website - Windycity Coin website

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  • TopographicOceans
    TopographicOceans Posts: 6,535 ✭✭✭✭
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    A sorting machine.
  • WoodenJefferson
    WoodenJefferson Posts: 6,491 ✭✭✭✭
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    Hasn't this been discussed here before?

    I don't remember the most accepted theory but I'm certain someone does.
    Chat Board Lingo

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  • JCLIGHTBRIGADE
    JCLIGHTBRIGADE Posts: 378 ✭
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    IIRC it was determined that this isn't the coin at all, but the slab...again IIRC.

  • ShadyDave
    ShadyDave Posts: 2,218 ✭✭✭✭✭
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    Originally posted by: JCLIGHTBRIGADE
    IIRC it was determined that this isn't the coin at all, but the slab...again IIRC.







    This coin isn't in a slab...

    Looks like PMD from a coin counting machine
  • LanceNewmanOCC
    LanceNewmanOCC Posts: 19,999 ✭✭✭✭✭
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    Originally posted by: JCLIGHTBRIGADE

    IIRC it was determined that this isn't the coin at all, but the slab...again IIRC.





    there is an effect that is sorta similar.



    lathe lines is what ive read as well.



    seen them on several type.



    Hasn't this been discussed here before?




    yup.



    would take some creative searching if one didnt know the useful terms to search.

    .

    <--- look what's behind the mask! - cool link 1/NO ~ 2/NNP ~ 3/NNC ~ 4/CF ~ 5/PG ~ 6/Cert ~ 7/NGC 7a/NGC pop~ 8/NGCF ~ 9/HA archives ~ 10/PM ~ 11/NM ~ 12/ANACS cert ~ 13/ANACS pop - report fakes 1/ACEF ~ report fakes/thefts 1/NCIS - Numi-Classes SS ~ Bass ~ Transcribed Docs NNP - clashed coins - error training - V V mm styles -

  • TomB
    TomB Posts: 23,188 ✭✭✭✭✭
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    I don't believe that is PMD. Rather, I think it was done during production at the Mint.
    Thomas Bush Numismatics & Numismatic Photography

    In honor of the memory of Cpl. Michael E. Thompson

    image
  • LanceNewmanOCC
    LanceNewmanOCC Posts: 19,999 ✭✭✭✭✭
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    Originally posted by: Hydrant

    It does appear to be the slab, as the lines are also on the main devises, not just in the fields.




    it is amazing what survives the strike of the die(s).



    adjustment marks are key to this point. image

    .

    <--- look what's behind the mask! - cool link 1/NO ~ 2/NNP ~ 3/NNC ~ 4/CF ~ 5/PG ~ 6/Cert ~ 7/NGC 7a/NGC pop~ 8/NGCF ~ 9/HA archives ~ 10/PM ~ 11/NM ~ 12/ANACS cert ~ 13/ANACS pop - report fakes 1/ACEF ~ report fakes/thefts 1/NCIS - Numi-Classes SS ~ Bass ~ Transcribed Docs NNP - clashed coins - error training - V V mm styles -

  • Windycity
    Windycity Posts: 3,603 ✭✭✭✭✭
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    Definately not the slab as the coin is not slabbed. It's raw, uncirculated and line are on the fields and devices. I am certain it is a minting issue... not pmd.

    <a target=new class=ftalternatingbarlinklarge href="http://www.mullencoins.com">Mullen Coins Website - Windycity Coin website
  • davewesen
    davewesen Posts: 6,981 ✭✭✭✭✭
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    Here is another thread saying they are lathe lines that are on the die used to strike your coin.

    https://forums.collectors.com/...yword1=die+lathe+lines
  • SoCalBigMark
    SoCalBigMark Posts: 2,851 ✭✭✭✭✭
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    D Carr was having that effect on some of his products.
  • dcarr
    dcarr Posts: 10,255 ✭✭✭✭✭
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    Those are "lathe marks" left over from machining a blank working hub or blank working die. When hubbed, the marks are not completely eradicated.

    Moonlight Mint
  • JCLIGHTBRIGADE
    JCLIGHTBRIGADE Posts: 378 ✭
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    I meant through the flip...take it out and then report back...

  • LanceNewmanOCC
    LanceNewmanOCC Posts: 19,999 ✭✭✭✭✭
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    fixed

    .

    <--- look what's behind the mask! - cool link 1/NO ~ 2/NNP ~ 3/NNC ~ 4/CF ~ 5/PG ~ 6/Cert ~ 7/NGC 7a/NGC pop~ 8/NGCF ~ 9/HA archives ~ 10/PM ~ 11/NM ~ 12/ANACS cert ~ 13/ANACS pop - report fakes 1/ACEF ~ report fakes/thefts 1/NCIS - Numi-Classes SS ~ Bass ~ Transcribed Docs NNP - clashed coins - error training - V V mm styles -

  • ctf_error_coins
    ctf_error_coins Posts: 15,433 ✭✭✭✭✭
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    Lath lines error
  • Windycity
    Windycity Posts: 3,603 ✭✭✭✭✭
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    Here's another image without shooting thru the flip. Just the coin and camera. This image also shows the same effect below the ear.

    image
    <a target=new class=ftalternatingbarlinklarge href="http://www.mullencoins.com">Mullen Coins Website - Windycity Coin website
  • MonsterCoinz
    MonsterCoinz Posts: 1,518 ✭✭✭✭✭
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    Weren't these called lathe lines? I think I remember Charmy doing a writeup about them if memory serves.
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  • astrorat
    astrorat Posts: 9,221 ✭✭✭✭✭
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    Originally posted by: Hydrant
    Dan, so I guess I was half right with my first answer. They were caused during the lathing. But why do the spiral lines show on the main devise. Wouldn't they be removed in that area during the engraving?


    Modern dies are not engraved. The devices are impressed on the die during the hubbing process. So, it is possible for what is on the surface of a working hub or working die prior to the "squeeze" to be impressed into the recessed areas of the devices.
    Numismatist Ordinaire
    See http://www.doubledimes.com for a free online reference for US twenty-cent pieces
  • CaptHenway
    CaptHenway Posts: 34,164 ✭✭✭✭✭
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    Originally posted by: dcarr

    Those are "lathe marks" left over from machining a blank working hub or blank working die. When hubbed, the marks are not completely eradicated.





    Sounds right to me. Perhaps there are variances in the lathe lines on die blanks caused by the cutting tool getting dull or some similar cause. Stronger lathe lines would be more likely to survive the hubbing process.



    Still in the realm of idle speculation, perhaps the die blanks are supposed to be polished smooth after they are lathed, and sometimes they forget to do so.
    Professional Numismatist, Retired. 55 year member ANA. Former ANA Senior Authenticator. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and ANA Lifetime Achievement Award 2020. Winner of the PNG's 2026 Robert Friedberg Award for "The Enigmatic Lincoln Cents of 1922," Available now from Whitman or Amazon.
  • mannie gray
    mannie gray Posts: 7,259 ✭✭✭✭✭
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    Agreed; they are lathe lines.
  • Zoins
    Zoins Posts: 34,489 ✭✭✭✭✭
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    It's great to see these lathe lines. Makes you think about how these coins are made.
    Private Mint News | 2010 Lincoln Reverse Finalists
  • kaz
    kaz Posts: 9,378 ✭✭✭✭✭
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    Very interesting, I am surprised that those lines don't go away during hubbing. I learn something new every time I log on here.
  • Coppercolor
    Coppercolor Posts: 1,475 ✭✭✭
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    This is, for whatever reason, very common on 1935P lincolns, where it's seen on the face. Lathe marks
    I'd like my copper well done please!
  • ricko
    ricko Posts: 98,724 ✭✭✭✭✭
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    I have seen this topic here before... and yes, determined to be lathe lines.... However,

    I have been searching for years for an example and yet to find one... so they seem to

    be scarce. Cheers, RickO
  • asheland
    asheland Posts: 24,545 ✭✭✭✭✭
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    Interesting thread

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  • oih82w8
    oih82w8 Posts: 13,206 ✭✭✭✭✭
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    Originally posted by: TomB

    I don't believe that is PMD. Rather, I think it was done during production at the Mint.




    I am with Tom, those look like lathe marks on the dies that were unfinished/hurried/etc... and were pit into production a little too early.



    (Should have read the whole thread before making my comment.)
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  • Icollecteverything
    Icollecteverything Posts: 1,033 ✭✭✭
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    I was thinking maybe this was just a modern thing but then I remembered this CWT.



    image

    Successful BST deals with mustangt and jesbroken. Now EVERYTHING is for sale.

  • TwoSides2aCoin
    TwoSides2aCoin Posts: 45,216 ✭✭✭✭✭
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    Emory (sp) image cloth is a tool and die guy's friend.
  • BryceM
    BryceM Posts: 11,940 ✭✭✭✭✭
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    FYI, RWB copied the OP's photo and gave his explanation of what this likely represents in a thread ATS.



    Link
  • leothelyon
    leothelyon Posts: 8,568 ✭✭✭✭✭
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    Here's a video. Well, I see the link is broke. Just Bing US Mint How coins are made to see the lathe in action.

    The more qualities observed in a coin, the more desirable that coin becomes!

    My Jefferson Nickel Collection

  • leothelyon
    leothelyon Posts: 8,568 ✭✭✭✭✭
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    Click here to see a couple more examples.

    The more qualities observed in a coin, the more desirable that coin becomes!

    My Jefferson Nickel Collection

  • jcping
    jcping Posts: 2,649 ✭✭✭
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    Originally posted by: CaptHenway
    Originally posted by: dcarr
    Those are "lathe marks" left over from machining a blank working hub or blank working die. When hubbed, the marks are not completely eradicated.


    Sounds right to me. Perhaps there are variances in the lathe lines on die blanks caused by the cutting tool getting dull or some similar cause. Stronger lathe lines would be more likely to survive the hubbing process.

    Still in the realm of idle speculation, perhaps the die blanks are supposed to be polished smooth after they are lathed, and sometimes they forget to do so.



    +1, very common on Calfracs. Usually, when these lathe marks shows, coins were well struck and many are top grade coins.
    an SLQ and Ike dollars lover
  • kaz
    kaz Posts: 9,378 ✭✭✭✭✭
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    The discussion between DCarr and RWB on the NGC forum is very informative. Thanks for the link BryceM
  • Unknown
    Unknown
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    This content has been removed.
  • Coppercolor
    Coppercolor Posts: 1,475 ✭✭✭
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    Here's as 1935 Lincoln I now own that has them on the forehead, cheek, neck and jacket. Hard to see in this image due to the toning and die polish but it's real obvious in person.

    image
    I'd like my copper well done please!
  • Broadstruck
    Broadstruck Posts: 30,497 ✭✭✭✭✭
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    I happen to find the lathe marks attractive as they add character image



    image
    To Err Is Human.... To Collect Err's Is Just Too Much Darn Tootin Fun!
  • Coinstudy
    Coinstudy Posts: 287 ✭
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    I was about to say lathe line from dies being turned
    Mark Anderson
  • dcarr
    dcarr Posts: 10,255 ✭✭✭✭✭
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    Originally posted by: kaz
    The discussion between DCarr and RWB on the NGC forum is very informative. Thanks for the link BryceM


    Interesting but also typical of a RWB/dcarr exchange (unfortunately).

    Note that I did just add conclusive pictures of a hubbing test that I recently performed.
    Moonlight Mint
  • BryceM
    BryceM Posts: 11,940 ✭✭✭✭✭
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    Dan,



    Nicely done experiment you presented ATS, and in line with my own expectations....... (used to teach a strength of materials lab while finishing my engineering degree).
  • nk1nk
    nk1nk Posts: 486 ✭✭✭✭
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    I find it unfortunate that RWB allows his disdain for Dan's overstrikes to prevent a very informative discussion. I see threads over AT coins produce over 20 pages of back and forth drivel and a few pages into a very good topic and he stomps his feet and takes his ball and goes home. Not what I would expect from such an esteemed researcher.



    Nick
  • kaz
    kaz Posts: 9,378 ✭✭✭✭✭
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    I think Dcarr's experiment pretty much settles the issue, as far as I am concerned.
  • BryceM
    BryceM Posts: 11,940 ✭✭✭✭✭
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    Dan,



    Have access to any conical die stock you can try this with? I'd be willing to put money on a wager that you'll still see plenty of artifact on the surface of the die making it into the final product.
  • grip
    grip Posts: 9,962 ✭✭✭✭✭
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    I have two 69-d from a obw that show the spiral marks. and was told by Alan Herbert? it was lath marks

  • dcarr
    dcarr Posts: 10,255 ✭✭✭✭✭
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    Originally posted by: BryceM
    Dan,

    Have access to any conical die stock you can try this with? I'd be willing to put money on a wager that you'll still see plenty of artifact on the surface of the die making it into the final product.


    I do not have any conical die blanks. I could always machine such thing. But I don't think it would be necessary to go to that trouble since I already know what the result would be.
    Moonlight Mint
  • BryceM
    BryceM Posts: 11,940 ✭✭✭✭✭
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    image
  • 19Lyds
    19Lyds Posts: 26,520 ✭✭✭✭
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    Originally posted by: dcarr

    Originally posted by: BryceM

    Dan,



    Have access to any conical die stock you can try this with? I'd be willing to put money on a wager that you'll still see plenty of artifact on the surface of the die making it into the final product.




    I do not have any conical die blanks. I could always machine such thing. But I don't think it would be necessary to go to that trouble since I already know what the result would be.



    True, but there will always be someone that thinks a conical die blank makes the big difference.

    I decided to change calling the bathroom the John and renamed it the Jim. I feel so much better saying I went to the Jim this morning.



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  • 3keepSECRETif2rDEAD
    3keepSECRETif2rDEAD Posts: 4,285 ✭✭✭✭✭
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    ...so why did dude run away? It hasn't been too long so maybe after the weekend he will respond. I don't know anything about what you guys are doing but I have read all the text and learned all I could learn without having any true passion involved...however, I did get my passion tapped into when Dan offered a simple wager. Put your money where your mouth is, even if you lose, no one can say that you are "hiding in a cacoon," for losing a fair wager...regardless of the price image
  • dcarr
    dcarr Posts: 10,255 ✭✭✭✭✭
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    Originally posted by: 3keepSECRETif2rDEAD
    ...so why did dude run away? It hasn't been too long so maybe after the weekend he will respond. ...




    I doubt it.

    He has made over 20 posts on that forum (in different threads) since I made my wager offer.

    But not a peep in that thread.
    Moonlight Mint
  • nk1nk
    nk1nk Posts: 486 ✭✭✭✭
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    Yeah he won't be back to reply. He's to busy commenting on possible camera toting pigeons as a security option at major coin shows and training them to poop on any thieves as a way to mark them until security can come and......I believe he said execute them. You know important numismatic topics.
  • TopographicOceans
    TopographicOceans Posts: 6,535 ✭✭✭✭
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    Originally posted by: dcarr
    Originally posted by: 3keepSECRETif2rDEAD
    ...so why did dude run away? It hasn't been too long so maybe after the weekend he will respond. ...




    I doubt it.

    He has made over 20 posts on that forum (in different threads) since I made my wager offer.

    But not a peep in that thread.
    Can I get $20 on dcarrimage

  • BryceM
    BryceM Posts: 11,940 ✭✭✭✭✭
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    There's no reason to be mean spirited. One of the reasons to spend time on a forum is to share information and bounce ideas off of each other. It's OK to be wrong once in a while, and RWB has forgotten more about coins than I'll ever learn. This has been an informative thread and there still might be more to the story behind lathe lines than we've seen. I do think Mr. Carr is on the right track though.

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