The Effect Of Cold Worked Metal On Toning.

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Author	Replies: 19 / Views: 3,284	Page: of 2
Chute72 Pillar of the Community United States 1314 Posts	Posted 05/08/2015 8:37 pm I'll present my understanding of the process and lay a foundation for more educated contributions. Moving metal molecules physically in relation to one another is called "working" the metal. If done in a cold environment it often changes the molecular structure making the metal harder. This is especially true of coin alloys. Properly calculated, a softer planchet gets "squished" into the shape of a coin between the dies. In addition to creating an image, it can harden the coin for durability. If not properly calculated, as is often the case with ancients, it can cause soft coins to wear prematurely or hard ones to crack at the time of initial hammering. In the case of our Morgan here, we can see where the metal was worked when it filled the outer devices and sheared over the top of them. The additional working caused a change in the microstructure of the metal crystals. It not only made the metal harder, it made the metal more resistant to external chemical reactions - toning. This is not an uncommon phenomenon, but one often overlooked for lack of an explanation. Report this Post to the Staff

ChildOfTheWheat Pillar of the Community United States 5828 Posts	Posted 05/08/2015 8:40 pm Wow. I never knew such a thing existed. Super cool, I learned something new today! Report this Post to the Staff
SilverStackerKid Pillar of the Community United States 6478 Posts	Posted 05/08/2015 8:56 pm Yes, you learn something new everyday. Very interesting. Report this Post to the Staff
SsuperDdave Moderator United States 23522 Posts	Posted 05/08/2015 9:19 pm Keep this in mind as a very reliable (but not infallible) indicator of natural toning. Report this Post to the Staff
publius Pillar of the Community United States 807 Posts	Posted 05/08/2015 9:58 pm There are some very interesting comments on this topic in the 19th-century Reports of the Deputy Master of The Royal Mint. Report this Post to the Staff
jbuck Moderator United States 187702 Posts	Posted 05/08/2015 11:43 pm I leaned something new today. Thank you very much for this. Coin Collector Since 1978 Avatar Old Avatar 7070 Eisenhower Australia Canada World CCF Members on eBay CCF eBay Search Engine Report this Post to the Staff
jack jeckel Pillar of the Community United States 5201 Posts	Posted 05/09/2015 12:16 am Thanks for the insight. I never knew of or even noticed that effect before. Report this Post to the Staff
bpoc1 Rest in Peace United States 4078 Posts	Posted 05/09/2015 06:59 am Chute72, Report this Post to the Staff
just carl Bedrock of the Community United States 20753 Posts	Posted 05/11/2015 11:18 am Interesting for sure. Report this Post to the Staff
Cascade Pillar of the Community United States 7390 Posts	Posted 05/11/2015 12:12 pm Are you talking about the pullaway chute? I didn't know it was an effect of the planchet. Report this Post to the Staff
aardspeed Pillar of the Community 921 Posts	Posted 05/11/2015 12:21 pm Some great reading on coin metals Great stuff on "Dave Hamric" http://periodictable.com/Elements/S...c/index.html http://www.elementsales.com/intro.htm Element Series "Coins" Beginning in 2006, Dave Hamric (Metallium) [5] has been attempting to strike "coins" (technically tokens or medals, about the size of a US cent) of every possible chemical element. To date he has struck tokens of the following elements. Aluminum Antimony Barium (reactive, sealed in glass capsule) Beryllium Bismuth Boron (mixed with binder, sealed in resin cast) Cadmium Calcium (reactive, sealed in glass capsule) Carbon (mixed with binder, sealed in resin cast) Cerium (reactive, sealed in glass capsule) Chromium Cobalt Copper Dysprosium Erbium Europium (reactive, sealed in glass capsule) Gadolinium Gallium Gold Hafnium Holmium Indium Iron Lanthanum (reactive, sealed in glass capsule) Lead Lutetium Magnesium Mercury (sealed in resin cast) Molybdenum Neodymium (reactive, sealed in glass capsule) Nickel Niobium Palladium Phosphorus (mixed with binder, sealed in resin cast) Platinum Praseodymium (reactive, sealed in glass capsule) Rhodium Ruthenium Samarium (reactive, sealed in glass capsule) Scandium Selenium Silver Strontium (reactive, sealed in glass capsule) Sulfur Tantalum Tellurium (mixed with binder, sealed in resin cast) Terbium Thallium (extremely poisonous. Lead token clad on one side with thallium foil and sealed in resin.) Thulium Tin Titanium Uranium[6] Vanadium Ytterbium Yttrium Zinc Zirconium http://en.wikipedia.org/wiki/Coinage_metals Edited by aardspeed 05/11/2015 12:22 pm Report this Post to the Staff
Chute72 Pillar of the Community United States 1314 Posts	Posted 05/11/2015 6:22 pm Cascade, Yes, I think that visual effect is sometimes called "pullaway." Report this Post to the Staff
Cascade Pillar of the Community United States 7390 Posts	Posted 05/12/2015 07:49 am Chute, I learned about pullaway on jhonEcash in reference to toning. A guess I just assumed it was a strike artifact related to the dies. Thanks for the higher learning! Makes alot of sense on why NT is prevented there now that I think about it Edited by Cascade 05/12/2015 07:52 am Report this Post to the Staff
just carl Bedrock of the Community United States 20753 Posts	Posted 05/13/2015 10:34 am Nothing mentioned as to the temperatures. At what temperatures is this supposed to be noticable? Enclosed environment? Any difference in humidity for those effects? Report this Post to the Staff
Chute72 Pillar of the Community United States 1314 Posts	Posted 05/13/2015 4:58 pm Warm or cool, humid or dry, the coin looks the same. No noticeable change if I close the door. But I rather suspect Carl, that's not what you meant. Can you rephrase the question? Report this Post to the Staff
SsuperDdave Moderator United States 23522 Posts	Posted 05/13/2015 5:43 pm You know, given that pullaway is common but not universal, I wouldn't be surprised if there were external atmospheric prerequisites as well. Then again, it occurs to me that strike speed/pressure is likely causative as well. Report this Post to the Staff
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