Author Topic: Change Molds of The GreatWall bronze medals (“HEROS”and“HEROES”)  (Read 6727 times)

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Offline RAREMEDAL

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上币共用“梅花长城”面的章不少,甚至民间厂家也剽窃用过;背面英文篆字印,也有多种,如“中国展览”篆字印、“中国造币公司”篆字印等等,在此,我们讨论一下“不到长城非好汉”篆字印版的英文HEROS错版(一)和HEROES正确版(二)两大品种铜章的模具。
http://blog.sina.com.cn/s/blog_609ac53d0100epij.html







篆字印的缺陷我推测可能是”翻模过程中没有翻好或发生了模具上金属屑的粘模“,我推测的两种成因中,我更倾向前者,即”翻模过程中没有翻好“。
理由:
如果是金属屑垃圾在模具凹槽,其垃圾屑硬度不足以造成这么多铜章的缺陷(推测模具凹槽内缺陷处成分极有可能是钢);
接着推……
87长城压印量很多,而且铸造批次不少,跨度可能有好几年(从上色和塑封推测出),一副模子不可能全都撑下来;(也不大可能持续数年未把模具垃圾清理掉吧?!)
压印量大,中间不会不修模清扫;
87银章、铜章皆有此缺陷,基本可以推测说明模子是清洁的、本身翻制出来就是个缺陷模;(因为压印上机之前要检查模子,贵金属压印更加如此)
87跟84、80不是用同一母模翻出来的,87是“翻改”版,篆字小印跟84、80的区别较大;正如我第一张图上标注文字所说:“层层翻铸,翻版越多,离最初版差别越大”,“篆字印英文”这一面,是被上币翻改多次的,87版应该是翻自较晚版本的章或模子,而不是80年代初期的母模,对比80和84,87篆字有明显的修模,亦或是重新仿刻的,断笔缺陷亦是在此过程即已产生,甚至有可能87版的一部分工作模,由于之前工作人员疏于检查,翻自本身即有缺陷的二元模。翻出来不同程度缺陷的模子,工作人员如果误以为篆刻本如此的话,可能会将一部分模子的缺陷修模”加强“。
--------------以上仅是本人根据藏品实物、造币知识推测出来的,非造币厂资料记载,如有可证实之谬误,欢迎指正。

(根据资料:80版错版照片、84错版长城紫铜4枚(不同上色、不同边缘)、84错版长城本色黄铜3枚(其中原封两枚)、84中国展览本色黄铜长城4枚(世博会中国馆纪念品)、87正确版长城紫铜3枚(不同上色、塑封不同、包装不同)、87正确版镀金铜章(原塑封无云版))
注:本色黄铜是指:H68黄铜材质,章表面没有上色,有些章出厂时表面喷有清漆。

★ H68黄铜有极为良好的塑性和较高的强度,可切削加工性能好,易焊接,对一般腐蚀非常安定,但易产生腐蚀开裂。为普通黄铜中应用最为广泛的一个品种。H68黄铜性能与H70极相似,但冷作时有,“季裂”倾向,用作复杂的冷冲件和深冲件,如波纹管。
化学成份:

铜 Cu :67.0~70.0
锌 Zn:余量
铅 Pb:≤0.03
磷 P:≤0.01
铁 Fe:≤0.10
锑 Sb :≤0.005
铋 Bi:≤0.005
注:≤0.3(杂质)
RAREMEDAL — Feng Jingjing sir. I come from He'nan of China.
I love chinese rare medals and golden and silver coins.
My E-mail:2209925761@qq.com
My blog:  http://blog.sina.com.cn/zhongyuanfeng555

Offline SANDAC

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My translation of RAREMEDAL's post.  I struggled with the technical portion so corrections are welcome.
-----------------------------------------------------------------------------------------------------
Shanghai mint's "plum flower great wall" obverse design was used for several medals.  It was even plagiarized by private mints.  The reverse seal also have several versions such as "China exhibition", "China mint", etc.  For now we are discussing the reverse dies of the brass medal for 1. HEROS error variety and 2.  HEROES variety

My conjecture regarding the flaws in the seal characters is either the working die was not duplicated properly or there were metal shavings in the working die.  Out of these two causes, I’m leaning toward the first, i.e., the working die was not duplicated properly.
Reason:
If the flaws were due to metal shavings in the recess of the working die, the hardness of metal shaving is not sufficient to cause so many flaws in the brass medal (the metal shavings are most likely steel);
Furthermore:
The mintage of the 1987 Great Wall is quite large and there were many lots, and spanning several years (deduced from the color and OMP seal), so one working die can’t handle all that (it is also unlikely that metal shavings were not cleaned out over the years!).

With large mintage it is not possible not to rework and not clean the die.
The 1987 silver and brass medal both have the flaws, so basically this indicates the working die was debris-free, that the flaws in the seal was in the working die as manufactured.  (because die should be inspected before installing on the press, more so for the precious metal press)

The 1987 is not minted with the same master die as 1984/1980.  The 1987 is the “revised” variety, the seal have many differences.  As described on my first picture: “duplicated repeatedly, the most duplicated has the greatest differences from the original”.  The seal-with-English-words side had been revised many times by the Shanghai mint.  The 1987 version probably was copied from the later medal or die, not from the 1980 master die.  Compare to the 1980 and 1984, the 1987 seal has obvious signs of repair, or possibly copied from scratch, thus the broken-stroke flaws were created.  It is even possible that the working hub of 1987 already had flaws that escaped inspection and created working dies with flaws such that different working dies have different degree of flaws; subsequently the mint worker mistook the flaws as the original design intent and exaggerated the flaws in the subsequent revision.

Above is my deduction based on actual coins and knowledge of coin production.  It is not based on mint’s records.  If the deduction is not consistent with actual records, corrections are welcome.

(Reference: photo of 1980 error variety, four purple-brass 1984 error variety coins with different color and edge, three original yellow-brass 1984 error variety coins (two with OMP), four China Exhibition original yellow-brass 1984 Great Wall coins, three purple-brass 1987 Great Wall coins (different color, different plastic seal, different packaging), a 1987 gilt brass (OMP, no-cloud variety).  Note: “original yellow-brass” refers to H68 brass.  No coloration on the surface of medal, some medal has clear coat as produced by the mint.

H68 brass has excellent ductility and high strength, good machining property, easy to weld, stable to most corrosive agents, but susceptible to corrosive cracking.  It is one of the widely used brass material.  The properties of H68 brass is very similar to H70, but when cold worked has “quarter crack” tendency, used for complex cold stamping and deep-drawing components such as the bellow.
Composition:
Copper Cu:67.0~70.0
Zinc Zn: 30.0-33.0 
Lead-Pb: ≤ 0.03
Phosphors P ≤ 0.01
Iron Fe: ≤ 0.10
Antimony-Sb: ≤ 0.005
Bismuth-Bi: ≤ 0.005
Note: ≤ 0.3 (impurities)

Offline pandamonium

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SANDAC the article states "The mintage of the 1987 Great Wall is quite large and there were many lots....."    Is he talking about the brass or silver too?   What is the large mintage number?..........

Offline SANDAC

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RAREMEDAL didn't explicitly state whether it was 1987 brass or brass/silver that had large mintage in multiple lots over several years.  The post is about brass medal, so I believe he was referring to the 1987 brass medal's mintage.

Offline pandamonium

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OK that makes sense.     Does the Great Wall 3.3 oz silver medal have 68 mintage total?   Does this include all 3 varieties?   Does 68 mintage apply to one variety?    I read different opinions...........

Offline mmissinglink

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Much thanks for providing the translation, SANDAC.

RAREMEDAL'S research is excellent.

Just so I have acorrect understanding of the chronology - in regards to the brass Great Wall medal with the Plum Flower design on the obverse (which has the "HEROS" spelling error), according to RAREMEDAL, this version was minted in 1984 while the corrected Plum Flower version (correct spelling of "HEROES") was minted in 1987?

So what about the Beacon Tower obverse design Great Wall brass medals? Were all of them minted in 1984 or 1987?

Finally, is there still not consensus on the minting years for the silver versions of the Plum Flower and Beacon Tower medals?

It feels like the more I learn about the Great Wall medals, the less I know about them.

Offline SANDAC

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RAREMEDAL suggests an important clue to the age of the Great Wall medals by looking closely at the seal.  He believes the seal's defects increased with each replication, that the 1980 seal was the original design intent and later date seals have progressively more defects.  He further believes both brass medal and silver medal of each generation were struck with the same die design, so I believe the same defects of the brass medal so carefully documented by RAREMEDAL are also in the silver medal of the corresponding years.  RAREMEDAL's pictures are excellent.  I cut out two seals from his 4-seal photo and put them side-by-side, make them black and white, increase contrast and annotate the differences between 1984 seal and 1987 seal.  I'm unable to see NGC's file photo clearly due to low resolution and highly reflective silver surface.  I hope forum members can examine their own matte plum flower Great Wall and see whether they can see the same defects.


Offline SANDAC

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While the quality of NGC file photos are poor, the image provided by fwang2450 of the 1987 proof Beacon Tower ( http://china-mint.info/forum/index.php?topic=4488.msg63737#msg63737 ) provided the vital clue I needed to figure out the NGC photos.  The key signature is the smashed vertical line pointed with the green arrows in the picture attached.  It turns out all the Beacon Tower (or type II) Proof known to me (i.e., 3260210-007 PF66UC, 3553424-005 PF67UC, 3684312-001 PF68UC, 3692382-001 PF63UC, 4153433-001 PF66UC, 2642540-001 PF66UC) have the same smashed vertical line and therefore are the 1987 vintage, according to RAREMEDAL's method of identification.

All the Plum Flower or (type I) Proof and MS that I know of do not have the smashed line and should be the 1984 vintage, according to RAREMEDAL's method of identification.

Offline mmissinglink

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Great comparison photos and detective work, SANDAC! Bit by bit there's a better knowledge base being built concerning these elusive Great Wall medals.