Message:

<p>[QUOTE=&quot;john65999, post: 8056642, member: 111931&quot;]Alternative Theories on What Caused these spiral marks on a coin?&nbsp; </p><p><br /></p><p>ALTERNATIVE THEORY I:&nbsp; &nbsp; </p><p>The arcs are uniform in size, occur throughout the coin including relief and tops of letters, and seem to have a common center of rotation. In these respects they resemble machining grooves made during trimming of rotating bar stock. </p><p>&nbsp; </p><p>The consensus was that these are so-called &quot;lathe lines&quot; made when the end of die stock was machined before the design was impressed. Sounds reasonable; however....consider another idea. </p><p><br /></p><p><a href="https://2.bp.blogspot.com/-KLP-wVb3SNk/WsUEMSrn7dI/AAAAAAAABXY/epZQhmCYTJ8E7AcxBQJzvVL1Hx5Na8VvACLcBGAs/s1600/1996%2BD%2BLathe%2BLines.jpg" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://2.bp.blogspot.com/-KLP-wVb3SNk/WsUEMSrn7dI/AAAAAAAABXY/epZQhmCYTJ8E7AcxBQJzvVL1Hx5Na8VvACLcBGAs/s1600/1996%2BD%2BLathe%2BLines.jpg" rel="nofollow"><br /></a></p><p><a href="https://2.bp.blogspot.com/-KLP-wVb3SNk/WsUEMSrn7dI/AAAAAAAABXY/epZQhmCYTJ8E7AcxBQJzvVL1Hx5Na8VvACLcBGAs/s1600/1996%2BD%2BLathe%2BLines.jpg" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://2.bp.blogspot.com/-KLP-wVb3SNk/WsUEMSrn7dI/AAAAAAAABXY/epZQhmCYTJ8E7AcxBQJzvVL1Hx5Na8VvACLcBGAs/s1600/1996%2BD%2BLathe%2BLines.jpg" rel="nofollow"><br /></a></p><p>Multiple impressions from the hub were required to create a complete working die. </p><p>As these impressions were made, all machining marks were obliterated beginning with the center and moving outward. No fine concentric lines would remain on the portrait or any other part of the finished die. </p><p>&nbsp; </p><p>Notice that the photo shows concentric arcs in both the field and relief. This is not possible using pressure transfer methods. (Assuming the hub was not defective....but then we would expect to see a lot of coins with this defect.) </p><p>&nbsp; </p><p>The likely cause comes from post-transfer finishing of the die.[/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