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WHAT TYPE OF COIN PRESS was used in the Bombay Mint in the late 19th Century?

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  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    Notice how the scratches do not flow down into the design and how the edge of the design remains sharp and un-tapered.
    These scratches would have been caused by something like a file or sand paper on a hard un-padded surface.
    It was not able to flex down into the design, the scratch is on the field only.
    The red circles show no scratches or tapering of the design.

    Notice how the scratches flow into the design and the edge of the design has a slight taper. Lines in yellow
    In order to flex into the design a wire wheel or other padded devise would need to be used.
    The lines seem to get deeper near the edge of the coin. Lines in green
    If this was the area of greater flow should we not see lines where the blue lines are?
    Notice how there is no tapering of the design where the blue lines are?
    Would this not be evidence of directional buffing?
    Notice how the dots are only distorted or tapered on one side?
    Did the metal just stop flowing when it hit the design?
    Why is there no flow of the design on the other side making it more oval shaped?
    Would this not be more evidence of directional buffing?

    I am not trying to argue or deny what others have posted, I am simply stating observations I see.
    I have been wrong before and I will be wrong again in the future.

    Just my 2 cents :)

  • AUandAGAUandAG Posts: 24,515 ✭✭✭✭✭

    Okay, I'm over it. I just collect coins and how they are created makes no difference to me. If the mint made errors in manufacturing, so be it and if some are rare that's a good thing, too. Nice to know how the mint works but it does not matter to the amature like me.

    bob :)

    Registry: CC lowballs (boblindstrom), bobinvegas1989@yahoo.com
  • OldhoopsterOldhoopster Posts: 2,930 ✭✭✭✭✭

    I love this kind of stuff. Yes, I agree that it's esoteric, but you never know when sidenote discussions like these can provide data for future researchers in others topics. Chances are that this isn't important , but you never know. That's why people do research.

    FWIW, when I first saw this, I was certain it was die polish/abrasion. But with the additional info from @messydesk I'm leaning towards die wear due to the press type. IMO, this is a very interesting thread (and I have no collecting interest in British trade dollars)

    Member of the ANA since 1982
  • CaptHenwayCaptHenway Posts: 31,499 ✭✭✭✭✭

    If I hammer die descending in a Counter-Clockwise direction (I have no idea what way the Bombay Mint's screw presses turned, but say for the sake of argument it is spinning CCW) hits a series of stationary planchets, which way do the die flow lines develop? In the same direction as the spin, or crosswise to it?

    Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
  • messydeskmessydesk Posts: 19,642 ✭✭✭✭✭

    @CaptHenway said:
    If I hammer die descending in a Counter-Clockwise direction (I have no idea what way the Bombay Mint's screw presses turned, but say for the sake of argument it is spinning CCW) hits a series of stationary planchets, which way do the die flow lines develop? In the same direction as the spin, or crosswise to it?

    The direction is influenced by the spin, but is not exactly in the same direction. If it were, then you'd see strictly concentric flow lines. Instead you see outward flow being redirected by some rotation of the die as it strikes the planchet, forming a spiral. The stronger the rotation, the closer you get to concentric lines. If there's no rotation, you only get the normal radial lines we're used to on US coinage (slightly influenced by the design of the coin). The magnitude of the rotation being different in Bombay and Calcutta is probably the reason the lines on the 1902-C are a little different from those on the others.

  • KOYNGUYKOYNGUY Posts: 101 ✭✭✭

    I do not believe the die and screw are solid and strike the blank at a low lateral angle. There has to be a joint that allows the die to compresses vertically, A low angle lateral strike would cause excessive die wear. If anyone is suggesting the spiral effect is due to the action of a screw press, I would respectfully disagree. Many coins made by screw presses show no such characteristics. J.P.

  • KOYNGUYKOYNGUY Posts: 101 ✭✭✭

    Reflecting on my statement, I do have to note that this is not likely in a perfect world or well equipped machine shop. God knows what conditions exist in Bombay and other provincial mints of India, Perhaps the screw and socket system were somehow jerry-rigged. Though the die were shipped from Great Britain, the minting equipment was probably repaired in the prov. mint.
    Perhaps both the die finishing (rotary wire brush) and a more solid screw press (repaired or re-engineered) setup are responsible for the unique look of these coins. J.P.

  • NysotoNysoto Posts: 3,759 ✭✭✭✭✭
    edited November 10, 2019 8:36PM

    @KOYNGUY:

    I do not believe the die and screw are solid and strike the blank at a low lateral angle. There has to be a joint that allows the die to compresses vertically, A low angle lateral strike would cause excessive die wear.

    Again, the pitch of a screw press is very steep, more like a worm drive than a screw, which does not impart a "low lateral angle." The intent is to drive vertical force, which could not be done with a high thread count. I will link a Coin World article with a picture of an actual 1830's screw press - note the "screw" and how steep the threads are:
    https://coinweek.com/education/numismatic-history/unique-items-1830s-vintage-coin-screw-press-from-frontier-deviercy-co/

    The screw presses used by government mints were much larger.

    From the article "An ingenious feature is the square shape of the iron driving rod, this mitigates the rotational force from the screw action that would otherwise torque the hammer die and cause uneven striking." The US Mint screw presses also mitigated the rotational force, but evidently the Bombay Mint presses did not.

    Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
  • OldIndianNutKaseOldIndianNutKase Posts: 2,700 ✭✭✭✭✭

    I remain unconvinced that the screw press had anything to do with the radial lines imparted to the coins. These lines certainly came from the dies as we see no evidence of radial transgression of the devices.

    Perhaps another explanation is that the radial lines were intentional to impart a non-mirrored field much like a reverse proof today.

    OINK

  • NysotoNysoto Posts: 3,759 ✭✭✭✭✭

    @OldIndianNutKase

    Perhaps another explanation is that the radial lines were intentional to impart a non-mirrored field much like a reverse proof today.

    So the Bombay Mint imparted symetrically spiral lines in the dies that were progressively heavier to the edge, while leaving the centers of the dies without these curved lines???

    Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
  • OldIndianNutKaseOldIndianNutKase Posts: 2,700 ✭✭✭✭✭

    @Nysoto said:
    @OldIndianNutKase

    Perhaps another explanation is that the radial lines were intentional to impart a non-mirrored field much like a reverse proof today.

    So the Bombay Mint imparted symetrically spiral lines in the dies that were progressively heavier to the edge, while leaving the centers of the dies without these curved lines???

    it would be much more difficult to modify the central part of the coin with a rotary tool. And probably not necessary because the center of the coin is occupied by the devices, which show no radial lines.

    OINK

  • NysotoNysoto Posts: 3,759 ✭✭✭✭✭

    @OldIndianNutKase said:

    it would be much more difficult to modify the central part of the coin with a rotary tool. And probably not necessary because the center of the coin is occupied by the devices, which show no radial lines.

    So when the Bombay Mint intentionally modified the outer portions of the dies with spiral lines using a rotary tool, they did not attempt to place the lines in the die centers because it was too difficult, and because of the central devices as shown below?

    Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
  • OldIndianNutKaseOldIndianNutKase Posts: 2,700 ✭✭✭✭✭

    "So when the Bombay Mint intentionally modified the outer portions of the dies with spiral lines using a rotary tool, they did not attempt to place the lines in the die centers because it was too difficult, and because of the central devices as shown below?"

    I think that the mint at that time in history probably used tools that are similar to those used by dentists today. There probably did not exist tools that would create the effect they desired internal to the devices.

    OINK

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    For the record

    I was invited back to rejoin the conversation. Thanks @Insider2 for welcoming me back! :)
    .
    .
    @messydesk Has taken the time to provide excellent photos and insight, he has a wonderful set and if you did not click on his link and take a look you are missing out. He has several of these to look at and compare, I trust his eye and his numismatic knowledge. He has the coins in hand and if he says he is seeing flow lines I would put a great deal of stock in his findings.
    .
    .
    @CaptHenway Has provided some great information & insight.
    If the die preparation process was done at one location or if the same process and equipment was used at each location they could all show very similar anomalies. It would then come down to looking for very slight variations. To muddy the waters a little further it would seem the photos posted show lines from several different things like die flow, die polish & die repair.

    "A die fresh from its final pressing and hardened will require deburring. This is a delicate manual process – at least when highest quality is demanded. Based on the photo, and this is only one image, the lines are from a rotating brass deburring tool used in Bombay for a “quick and acceptable” job just before tempering. This would have been standard procedure at Bombay.
    In the photo, it is clear these are mechanical byproducts. They are almost perfectly parallel, similar in depth, similar in length and affect only one side of relief elements (pellets, etc.). These are all characteristic of use of an external tool, not a press. (Flip the image and one can more easily see that tool scratches always affect the same trailing arc of raised elements. When less pressure was used, the tool made lighter, thinner scratches, possibly not affecting relief.)"

    This would seem to agree with what I said earlier. Basically the die itself was "whizzed," and then hardened."
    .
    .
    I still believe the OP coin shows a classic example of polishing. I have buffed & polished quite a few items in my days
    I see some slight variations on some of messydesk's coins that could be related or unrelated but raise a question.

  • OldIndianNutKaseOldIndianNutKase Posts: 2,700 ✭✭✭✭✭

    To add to my previous comment that the lines were intentional by the mint, there is no connection to the lines being radial relative to the press. The lines are radial because this allowed for more distance between the devices to "impair" the fields of the coin to achieve the desired effect. And this could only be done on the perrifery of the die due to tool limitations.

    OINK

  • CaptHenwayCaptHenway Posts: 31,499 ✭✭✭✭✭

    @messydesk said:
    So here are some pictures from a few of my coins. I photographed elements near the edge, which is where flow lines are strongest. For the obverse, I used the head of the trident, for the reverse, I chose an area where lines were consistently strong (about 8:00). Then I took a bonus picture. Both Bombay and Calcutta mints are represented. The coins show various die states. I don't have the 1925 or 1930 London coins, so couldn't compare. In all cases, the direction of the lines was consistent, if not identical. Die polishing wouldn't accomplish this. Also, denticles were warped in the same direction.

    Draw or adjust your conclusions accordingly:

    Obverses
    1898-B

    1902-C - LDS dies. Note the shape of the denticles and the distorted corners of the design at the left and right edges of the picture

    1902-C - LDS dies. Note the shape of the denticles

    The 1902-C LDS fascinates me. Look at the denticles. Denticles are formed by a series of holes in the die. If the die erodes from usage, then the holes should theoretically get wider and deeper, making the denticles larger, and yet the denticles get thinner and distorted. Presumably the field near the denticles was worn down, making the denticles smaller, at the same time that the die erosion was reshaping the denticles all in the same direction. The more I look at it, the more I think it was the result of repeated strike die erosion, rather than a mechanical scouring of the die with a rotary brush.

    This coin may be the key to this fascinating discussion. You wouldn't by any chance happen to have a closeup picture of the opposite side of the coin at the same point? I am still trying to figure out how the rotary die action is transmitted through the planchets to the opposing die. On one side of the coin you have the die hitting the planchet. On the other side of the coin you have the planchet hitting the die. Will the effects upon the two dies be the same? I don't know.

    TD

    Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
  • messydeskmessydesk Posts: 19,642 ✭✭✭✭✭

    @CaptHenway said:
    This coin may be the key to this fascinating discussion. You wouldn't by any chance happen to have a closeup picture of the opposite side of the coin at the same point? I am still trying to figure out how the rotary die action is transmitted through the planchets to the opposing die. On one side of the coin you have the die hitting the planchet. On the other side of the coin you have the planchet hitting the die. Will the effects upon the two dies be the same? I don't know.

    TD

    I'll check tonight and post a photo. Both of my 1902-Cs have pretty extreme smeared denticles.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    @messydesk "They're polishing lines. Flow lines would start to blur the dots and the corners of the encircling pattern."

    +1

  • messydeskmessydesk Posts: 19,642 ✭✭✭✭✭

    @ifthevamzarockin said:
    @messydesk "They're polishing lines. Flow lines would start to blur the dots and the corners of the encircling pattern."

    +1

    That was before I looked at a lot of coins. Then I changed my mind.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    If nothing else we are giving you a good reason to look at & enjoy your coins. ;)

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭

    @ifthevamzarockin said: "For the record"

    "I was invited back to rejoin the conversation. Thanks @Insider2 for welcoming me back!"

    For the record, I have no control over what goes on at the CU forum. This member took himself out of this thread because of my posts. I told him to get his butt back. :)

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭
    edited November 11, 2019 10:14AM

    Two turn of the previous Century dollars from the Straits Settlements. One struck in Bombay one struck in England. One with the beginnings of curved radials imparted by the screw press in Bombay. The other struck with a modern press showing the normal radial direction as the dies started to wear. See the difference?

    There is NO EVIDENCE of die polish on either coin!

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭

    @ifthevamzarockin said:
    @messydesk "They're polishing lines. Flow lines would start to blur the dots and the corners of the encircling pattern."

    +1

    Please...

    You are posting as if you are a long-time, very knowledgeable, professional numismatist. That is the main reason I welcomed your "respectful disagreement" in the first place. I wrote "excellent" and waited to be "schooled."

    The cause of the "lines" has been discussed, proved using images, and ANSWERED by folks more knowledgeable than either of us. :)

    The post you quoted and agreed with (+1) no longer applies as this member found enough proof on his own coins to change his mind. Hopefully, your opinion will also change. Any more NONSENSE about die polish will probably confuse less knowledgeable members than yourself.

    PS Aside from, "I have buffed & polished quite a few items in my days," I'll be extremely curious about your numismatic experience with world coins if you continue to post your "OPINION" in this discussion. Thanks in advance. :)

  • jmlanzafjmlanzaf Posts: 31,618 ✭✭✭✭✭

    It still seems to me more likely that what we are seeing is die damage rather than metal flow lines. The flow lines should radiate away from the point of pressure, shouldn't they? I don't how you would curve that flow even if there was some shear due to twisting of the die.

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭
    edited November 11, 2019 12:03PM

    Die wear is die damage from use. It varies in degree. My original image was an extreme case!

    The appearance of the "die damage" (resulting from the interaction of planchet metal with the die's surface) on coins has been shown in this discussion to involve the way the coin was made. For example, the die wear (damage from use) on an ancient coin is different from a modern coin.

    I started to post the uni-directional, parallel flow lines (Oops! die damage) present on a concave Austrian piece struck using roller dies but feel this will only cause more confusion. Self EDIT o:)

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    Took a moment to try to reproduce what I am seeing. Mind you this is a quick attempt and I have not tried to reproduce this effect before. I took a piece of plate steel and cut a line in it & drilled a hole. I attempted to cut denticals but that is not easy so please forgive that they are a little sloppy. I made an impression in some putty in an effort to show it like it would be on a coin. I then buffed it with a wire wheel and retook some photos. I was able to produce much of what I am seeing.

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭
    edited November 11, 2019 2:41PM

    The images did not come up...However, I can take a piece of clay and a plastic fork and make grooves in the clay as on this coin. :p

    Now, rather then experiment, go on line and find one coin dated after 1836 with Mint die polish that even remotely resembles this.

    Class over, it is recess time.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭
    edited November 11, 2019 2:58PM

    @Insider2 "You are posting as if you are a long-time, very knowledgeable, professional numismatist."

    WOW!!!! You know nothing about me or my background.
    How do you know I am not a very knowledgeable, professional numismatist?

    No need to get your panties in a bunch! :D

  • CaptHenwayCaptHenway Posts: 31,499 ✭✭✭✭✭
    edited November 11, 2019 5:55PM

    Has anybody asked our resident coiner, Dan Carr, for his opinion?

    Edited to add: We probably cannot ask Dan to build a screw press and use a pair of crown-sized dies to strike several hundred thousand large silver planchets from them. However, perhaps he could take an obsolete die with denticles on it (if such a thing exists in his inventory) and attack it with a motor-driven rotary wire brush to see if and how die erosion lines develop.

    Personally I am liking the angular striking flow lines theory more and more, but it might be informative if we could confirm, or eliminate, the rotary brush flow lines theory.

    Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
  • messydeskmessydesk Posts: 19,642 ✭✭✭✭✭

    @CaptHenway said:
    Has anybody asked our resident coiner, Dan Carr, for his opinion?

    Ron Landis might be the better option.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭
    edited November 11, 2019 9:24PM

    My quick attempt to reproduce what I am seeing taught me quite a bit. I was not able to spend a great deal of time with it because I was at work. The results I got were encouraging for just grabbing the first thing I could find. I was able to play with it a bit more after I ran the first test and took the photos and saw some improvement. I think if I spend a little more time or plan things out I may be able to duplicate stage by stage the erosion of the denticals. The die would have been hardened and who knows what the wire wheel was made of....brass, stainless steel, copper etc. There is no way I can duplicate exactly the metals used over 100 years ago but I may be able to come up with a combination that produces very close results. I will need to find several different types of metal and several types of wire wheels and run a few tests. I also need to come up with a way to cut better and more even denticals as this could change the results. It will take a little time, I will not have this done tomorrow or the next day....or maybe even next week. If I am able to produce anything worth noting I will post an update here or I may start a new thread so the title is not changing all the time.

    I could very easily be wrong but I sure hope not.
    This would help me with my life long dream to finally become a "long-time, very knowledgeable, professional numismatist."
    :)

    Edited to add:
    I just realized that I will need to use a disk shape rather than a straight edge like on my test.
    The wire wheel will grab the edge of a round surface different than a flat surface and the wires will flex differently.

  • OldIndianNutKaseOldIndianNutKase Posts: 2,700 ✭✭✭✭✭
    edited November 12, 2019 12:18AM

    I find it very special that only a "numismatist" is competent to analyze "flow" lines on a coin. This would seem to me to be best left to those that are involved in the production of mint equipment and issues surrounding the quality control of the coins produced. Those that have explicit knowledge of minting presses and the metallurgy of the metal would seem to have more logical input than those whose credentials are of just grading coins.

    When we start with a basis that the grade of a coin is based upon condition as it left the mint, then we are electing to ignore any mint flaws that might detract from the coin. Some of us think that flow lines are just as distracting to a coin's perfection as PMD hairlines.

    Coins as minted are not perfect, which seems to be a point of reference that can be very subjective.

    OINK

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭

    @OldIndianNutKase said: "I find it very special that only a "numismatist" is competent to analyze "flow" lines on a coin."

    _"Special?" I regard a person who would think that to be ignorant_.

    "This would seem to me to be best left to those that are involved in the production of mint equipment and issues surrounding the quality control of the coins produced. [Thankfully, the folks you mention share this knowledge. There is not much "new" under the sun to learn about how coins were made over the ages.
    Those that have explicit knowledge of minting presses and the metallurgy of the metal would seem to have more logical input than those whose credentials are of just grading coins."

    A Numismatist studies things dealing with coins. For some, this includes how they are made. You don't need to actually make a coin to learn how it is done or what it looks like. This information has been passed down (even modified in some cases as more is learned) by those who make the actual coins, study them, publish, or SELL them as major dealers.

    "When we start with a basis that the grade of a coin is based upon condition as it left the mint, then we are electing to ignore any mint flaws that might detract from the coin. Some of us think that flow lines are just as distracting to a coin's perfection as PMD hairlines. Coins as minted are not perfect, which seems to be a point of reference that can be very subjective."

    Agree! Coins made with broken, worn, or damaged dies - are very detracting to many collectors. Many other collectors love them as they provide insight into the minting process and what can go wrong. PMD and hairlines are entirely different things. To eash his own._

  • NysotoNysoto Posts: 3,759 ✭✭✭✭✭

    @ifthevamzarockin:

    I just realized that I will need to use a disk shape rather than a straight edge like on my test. The wire wheel will grab the edge of a round surface different than a flat surface and the wires will flex differently.

    A disk shape would better simulate a die, along with a putty model of a "coin" from it. One thing that will be different on the experiment is the wire brush lines will be straight and not in a symmetrical spirals as in @messydesk's images. But there is way the spiral lines can also be simulated: I would expect the metal used is A36 or other mild steel. Cut a few dentils as on your other example, and set the disk in a lathe at slow speed, then proceed to use the rotary wire wheel on the outer part of the disk. The rotational movement of the lathe will cause the lines to be spiral, as on the images of the coins in the thread. And after awhile, the outermost portion of the disk will show the largest deformity of the "dentils" because the speed is the greatest on the edge. There you have it - a close simulation to the coins of this thread, but with some distinct differences. You will have proved that wire wheels can make a similar pattern of spiral lines on a steel die.

    However, there is a Catch 22 to the above. What it will prove is the coins in this thread were struck on a screw press, and the spiral lines are flow lines from late die stage deterioration. The lathe simulates the turning of the screw press. Think about it - what does the coiner want in the final clean-up of dies after hardening and tempering? A quick removal of any firescale or other impurities. They did not lap dies with a lathe and rotary wire brush, and they definitely did not want to destroy details of a die before it was used. The spiral lines are from die deterioration on a screw press that did not control the rotation of the screw/hammer die interface.

    Robert Scot: Engraving Liberty - biography of US Mint's first chief engraver
  • dcarrdcarr Posts: 7,936 ✭✭✭✭✭

    I was recently messaged and asked to give my opinion on the issue.

    If the dies were "whizzed" or deburred in some way, those effects would gradually diminish and be over-taken by normal radial die erosion. Also, there is no reason to deburr a die that has been hubbed since the hubbing process doesn't generally cause burrs to form (except maybe for the very outer corner of the die face).

    If a screw press were to rotate counter-clockwise (when viewed from above) it could potentially impart a counter-clockwise torque to the die. Imagine a situation where the screw press comes down and "slaps" the back of the upper die. An important metric would be the coefficient of friction between the press and die, as well as the coefficient of friction between the die and planchet. There would need to be some friction between the press and die to impart any torque. Also, as the die penetrates into the planchet, design elements would tend to lock the die into place and prevent it from rotating.

    And if the upper die was allowed to rotate a tiny bit, the cumulative effect of repeated strikes would result in a significantly rotated die.

    However, a die could still twist a small amount under torque and then spring back once relieved. To produce the effects shown, the twisting motion would NOT have to be anywhere near as much as you might think. A microscopic amount of twist, over a large number of strikes, could cause much longer spiral trails to form in the die face.

    And supposing that the lower die is fixed securely in place, given that the planchet is free-floating and not fastened to either die, a microscopic twisting motion of the upper die of X degrees (in relation to the lower die) would result in a twist of X/2 degrees between the upper die and planchet, and a twist of X/2 degrees between the planchet and lower die. This assumes the coefficient of friction between the upper die and planchet is similar to the coefficient of friction between the planchet and lower die.

    The direction and characteristics of the spiral trails on both sides of all the coins I looked at are consistent with a counter-clockwise screw press, with the upper die being not 100% securely held in place.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    First off I would like to thank everyone in advance for being patient with me while I make a little larger a$$ of myself. :)

    Please keep in mind that 3 very knowledgeable numismatic professionals have given their opinion on this matter.
    Thank you to @dcarr , @messydesk & @Insider2 for your thoughts & insight. :)
    Their thoughts & opinions should not be taken lightly and the combined years of experience far exceeds many on the boards here. Their dedication to numismatics and our fun little hobby has been immense and deserve respect. As I mentioned above I very easily could be wrong.
    I am only providing my findings to let everyone come to their own conclusion. I am not trying to argue or be confrontational but I honestly believe my finding are enough to raise a question and further the conversation. The photos messydesk has provided show many different features such as early or late die stages along with die flow and there is no way I can duplicate all of the variables seen on his coins. The OP coin is the one that I have been trying to duplicate the features shown.

    I have been running a few tests other than the one I posted. I have been able to produce many of the effects but need to refine it a little more. I am using softer metals than a hardened die and am having to make adjustments to compensate. I am finding the are many variables and it is proving to be a challenge. At this point I am not sure that even if I was able to produce an exact duplication that I could change any minds. I'm not sure how much of this really even matters in the coin world, either you like the coin or you don't.

    I tried another test on 11/20 with some aluminum, it didn't work well at all. I am using soft metals and just not getting the desired effect, I may need to harden my next test. When we think about a wire wheel for buffing or polishing the most common one is one like this, it might be on a bench or hand held. The problem is when the wheel rotates it flexes the wires and the side of the wire is what is coming in contact with the surface. It leaves more of a textured surface and moves quite a bit of metal.

    This type of a wire buffer is the type that was most likely used to make the spiral pattern. With this type the tips of the wires are doing the work, they are sharp and able to scratch rather than texture. Dies that they were more worried about quality may have been buffed with a cloth wheel after this type of brush was used. This is the type of brush used for the photos here.

    There are some very tough critics on the boards here, I need it to be better than what I have been able to produce so far.

    I have been able to do a total of 7 tests so far and have over 100 photos of the steps I am taking.

    Here are a few photos to show you what this type of brush will do. If the brush or die are able to move at all or were held by hand you will get a spiral effect rather than just a circle. Notice how the lines get deeper near the edge between the denticles even though the same amount of force was applied. Notice also how the dot is pulled in one direction. I know I need to make a better example but I think this shows the basics of what is going on. Once you see the similarities of the dots I believe it becomes harder to discount the fact the die was polished. Once a die is polished any number of variables can come into play to create other features.

    The angle of the brush to the die changes the swirl pattern. Without using a hardened die and knowing the exact shape of the brush used it is hard to get an exact match. The brush may have been designed a slightly different way 100 years ago and the metal used to make the brush is an unknown the speed of the brushes rotation is a big factor also. Each mint worker may have played a part in the variations also, as an example right or left handed, the amount of force applied or the amount of damage that was being corrected.

    Notice how some of the polish lines are starting to angle or deflect slightly.

    This was another test 11/27 where a brand new brush was used with the same methods as before. The test piece was slightly larger and the brush was slightly smaller to get a little more arch to the lines. I was surprised how much difference the new brush made, it cut quite a bit deeper with the same force applied. This just shows how much a small variable can change the outcome of the test.

    Then I pushed it just a little further to try to show the effects better.

    Next you can see how I was able to get the denticles to arch or curve slightly. This can also be seen slightly on the earlier test.

    Thank you for taking the time to read and review my findings. All comments are welcomed and much appreciated! :)
    I am not sure how many more tests I will do or if I will spend any more time with this. If I spend more time and am able to produce better results I will post an update.

  • KkathylKkathyl Posts: 3,762 ✭✭✭✭✭

    Since they outsource the product from India Government to Britain cannot answer the question without knowing the exact coin. So if trick question the answer is none.

    Most
    early was hammered but then milled when they colonialism’s took place notes say swirling and hairline can be irregular so you have to check how it flows under device. A lot of restrikes and counterfeit as well. It’s a chase the tail but you should have a l or a b as mintmark

    Best place to buy !
    Bronze Associate member

  • CaptHenwayCaptHenway Posts: 31,499 ✭✭✭✭✭

    I appreciate your continuing efforts to answer the question. We may never reach an answer we can all agree on, but we can enjoy the journey as we go!
    TD

    Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭

    @ifthevamzarockin,

    Thanks and GREAT WORK! You are being too modest as this is the type of research that can blow "old myths" and get us old "dinosaurs" thinking.

    So far you have not produced the "swirl effect" seen on these screw press coins. You have produced very nice concentric lines - similar to the lathe lines we can often find on U.S. coins where the die was not properly finished.

    Another thing that has not been duplicated is the intensity of the curved die flow which is first seen as just a hint around the denticles that progresses, getting longer and longer until we have the surface I imaged in the OP.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭
    edited November 30, 2019 9:08AM

    So far you have not produced the "swirl effect"

    I agree, the swirl effect is hard to duplicate but as mentioned the angle of the brush to the die has much to do with it. I have produced "similar" but not exact, you can see some of the swirl effect here at about the same rate of swirl. For my tests to be consistent I had to remove some variables. With mine the sample & the brush are secured in one spot rather than one or the other being held by hand and able to move.

    Edited to add: "You have produced very nice concentric lines - similar to the lathe lines"
    This statement is 100% correct

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    Sometimes when dealing with problems I find it is easier to take things one step at a time. You need to walk before you run.
    Do you or anyone here see the similarities with the dots?

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    "get us old "dinosaurs" thinking."
    If I have accomplished this I can stop right here. :)

    I am no spring chicken myself. :D

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭
    edited November 30, 2019 6:26PM

    While I admire and applaud your effort so far - I think your theory of die polish is very flawed. I've seen many hundreds of these coins over the years and will post more images sometime. Nothing you have shown matches anything that duplicates the actual coins or the coin I posted. I hope you will continue with your experiments.

    Here is one: Take your clay and a piece of fine-grade sandpaper. Lay the sandpaper on the clay and twist it. Next, take a coarse grade of sandpaper and do the same thing. You should be able to see a hint of swirls in the first test (new die) and deep swirls in the second (very worn die used in a screw press).

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    @Insider2 "Nothing you have shown matches anything that duplicates the actual coins or the coin I posted."

    Do you see the similarities with the dots?

  • messydeskmessydesk Posts: 19,642 ✭✭✭✭✭

    @ifthevamzarockin said:
    @Insider2 "Nothing you have shown matches anything that duplicates the actual coins or the coin I posted."

    Do you see the similarities with the dots?

    There are similarities in the effects seen at the dots, and in both the case of flow lines and polishing, I would expect to see the same effect in a local area. They are both cases of metal moving across the face of metal. In the case of flow lines, it is a microscopic amount at a time between each of many strikes, and in the case of polishing, it's a lot all at once between two strikes. In comparing flow with polish, they could be moving in the same direction.

    Once you look at the entire coin there's a problem with die polishing that you've noted already. The lines sort of spiral out from the inside of the coin to the rim. It's also not a precise spiral, because some lines head to the rim faster than others (i.e., the radial flow is stronger there). A rotating polishing tool couldn't do this, but would produce something more like lathe marks. But let's say you could sort of do this with a little effort by tilting the rotating bit a little. You would still have to reproduce it the same way on every die you polished.

    I checked to see if I have duplicate BTDs in my set that are from the different die stages of the same die pair, and I don't.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    @messydesk, Thank you for taking the time to respond and check your other coins. :)

    "In comparing flow with polish, they could be moving in the same direction."

    I believe you may have hit the nail on the head. The polishing damage under pressure may very easily cause die flow or erosion that flows with the polishing lines. A combination of both could cause much confusion.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    "You would still have to reproduce it the same way on every die you polished."

    I have no idea of the set up used but I would guess they had a S.O.P. Some type of bench mounted buffer with a grove or slot to hold the die might produce fairly consistent results with slight variations. Just a dumb guess on my part, I wish I had a better idea of the set up because it would make it much easier to reproduce.

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭
    edited December 1, 2019 6:37AM

    @ifthevamzarockin said:
    @Insider2 "Nothing you have shown matches anything that duplicates the actual coins or the coin I posted."

    Do you see the similarities with the dots?

    NO! After examining your wonderful attempts to duplicate what we can see on the coin, I used the word "NOTHING."

    Look, I don't have a closed mind on anything except for the existence of One who shall remain unnamed. I'll be the FIRST to change my mind on any subject (taboo ones included) when I become better "educated" about something from someone who knows what they are talking about. That's because we learn WHAT WE DON'T KNOW from others.

    Therefore, your experiment was welcomed and "got me to consider your opinion." As I wrote, it made me think. When I was done thinking, I responded with my opinion and used the word "nothing" because it can be confirmed by looking at the images you posted in comparison with the image of the coin. :)

    PS As soon as someone suggested die polish, I considered that or a combination of polish and die erosion.
    I rejected BOTH opinions.

  • ifthevamzarockinifthevamzarockin Posts: 8,498 ✭✭✭✭✭

    If it shows diagnostics of being buffed/polished the method used may never be discovered. I did find in my tests that small changes can make a big difference. The diagnostics of directional polishing are like a map, some look at the map and get lost others look at it and find their way. Like I said "I am only providing my findings to let everyone come to their own conclusion." It is clear that IF I were to do another test my sample would need to be round and the exact size of a BTD. It would also seem clear that only few care from the lack of responses. I have already spent over 40 hours of my life on tests that I will never get back, I'm not sure I will spend any more. At least I ran some test to back up what I am seeing and I don't see anyone else doing diagnostic tests to back up what they are saying. Many of my results are not shown here but I was able to learn a great deal from them. With all the variables I realized it was more about getting back to basics and looking for the simple answer rather than over thinking it. If directional polishing can be diagnosed the method is secondary, they are two different problems with different answers. Just because the polish lines don't conform with what we think of when we think of polishing lines doesn't mean that is not what they are. The lines don't conform with typical flow lines either. Much like determining if a coin is counterfeit, everything can look right but you only need to find one thing that looks wrong, you may not know how they did it.

    @Insider2 Do you see the similarities with the dots? "NO! After examining your wonderful attempts to duplicate what we can see on the coin, I used the word "NOTHING."

    Sorry you are not able to see it. If I run more tests I will also work on a clearer way to display my findings.
    "Take your clay and a piece of fine-grade sandpaper." If you understand the properties of either material you would understand why this will not work. The clay would plug or fill the paper before any noticeable lines could be produced. But thanks for the suggestion as it keeps me thinking outside the box for further tests if I decide to do any.

  • Insider2Insider2 Posts: 14,452 ✭✭✭✭✭

    @ifthevamzarockin said:

    "Take your clay and a piece of fine-grade sandpaper." If you understand the properties of either material you would understand why this will not work. The clay would plug or fill the paper before any noticeable lines could be produced. But thanks for the suggestion as it keeps me thinking outside the box for further tests if I decide to do any.

    I guess you are using SOFT, MUSHY, children's modeling clay as your planchet. :)

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