Message:

<p>[QUOTE=&quot;yakpoo, post: 781583, member: 18157&quot;]MDD (Machine Double Die) is more accurately referred to as &quot;Strike Doubling&quot;. The cent in question is a very good example of Strike Doubling. Strike Doubling is caused by excessive force during the strike. It can be distinguished from a true Doubled Die by the flatness of the underlying device...as if it were &quot;sheered off&quot; by the die. The underlying device of a true Doubled Die is more rounded.</p><p>&nbsp;</p><p>A Doubled Die isn&#039;t caused by the strike of the coin, but rather by the hubbing of the die itself. As I recall, the hubbing process (creating a working die from the master die) is a multi step process. If, after the first strike, the working die is too brittle, it is sent back through the annealing process (heating and cooling) to strengthen the die. The die (already struck once) must be aligned exactly for the subsequent strikes. If it isn&#039;t, doubling occurs. There is usually some focal point of the rotation. Devices further from the focal point exhibit greater doubling. That&#039;s my understanding, anyway...hopefully the experts will correct me if I&#039;m wrong.</p><p>&nbsp;</p><p>Page #324 of the CherryPickers&#039; Guide, Vol 5 has a good example of the 1969s Doubled Die and Strike Doubling.[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in