Anyone collect lathe mark errors.
Peaceman
Posts: 5,098
It would seem that this kind of error (Happens on other types too) is rare from the feedback I've received on other boards....
0
Comments
Looking for Top Pop Mercury Dime Varieties & High Grade Mercury Dime Toners.
1866 S1-8001
http://www.shieldnickels.net
Are these concentric or spiral?
The Penny Lady®
look out, call the contractor, my head is getting so big, gonna have to widen the doorways
at my house just to get in
Go BIG or GO HOME. ©Bill
One possible thought on newer coins is that the die is spun and laser treated. A laser would make marks on both the fields and devices.
I don't think this is likely it it could be that the lathe marks were on the planchet and survived the striking. --jerry
--Jerry
If you look at the Stewart blay 1935 in PCGS 68RD you can see them there as well. Blay 1935P Lincoln
I suspect this is an indication of very EDS.
<<Edited to add link>>
As for spiral or concentric? I expect a little of both but more than likely a fine spiral.
The OP's Kennedy is Cool and Notable. Is it from the 80's?
The name is LEE!
oh yeah... can we have the year and mint on that Half? So we can keep an eye out for others.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
But if the marks cross over the devices, then it is probably due to a reduction lathe artifact. In such a case, the lines would be found on the master hub (or on the central device punch). I've engraved countless dies using the equivalent of a digital reduction lathe, and I've experienced those concentric circular lines (actually a fine spiral). In fact, it seems that things have to be set up just right to avoid getting them.
When I was restoring my Denver Mint surplus Grabener coin press, one of the things I found in the oil pan was a 34mm John Adams President medal (with a"D" mint mark). The die for this medal was apparently made on a reduction lathe from an original 3 inch version of the medal. Since the model was smaller than normal (3" vs. 8" or 9"), the result had softer details and more lathe marks than normal.
Note that the "D" mint mark is sharp because it was created by using a normal "D" punch applied to the die after it was machined. Also note that the same type of machining marks seen in the bottom picture above can also be seen in some places on the big silver ATB "hockey pucks" (like on the designer's initials, for example). This is becaue the large ATB dies are individually machined using a digital reduction lathe process similar to what I use.
Here is an example of one of my dies that had lathe marks. The lines can be seen on Liberty's skirt, and across the arm holding the torch. These lines were caused by inaccuracies on the Z axis of the engraving machine.
PS:
As a side note, it seems the US Mint 34mm bronze President medals with a "D" mint mark are under-appreciated and considerably scarcer than the Philadelphia versions.
Successful BST Transactions!SIconbuster, Meltdown, Mission16, slothman2000, RGjohn, braddick, au58lover, allcoinsrule, commemdude, gerard, lablade, PCcoins, greencopper, kaz, tydye, cucamongacoin, mkman123, SeaEaglecoins, Doh!, AnkurJ, Airplanenut, ArizonaJack, JJM,Tee135,LordMarcovan, Swampboy, piecesofme, Ahrensdad,
(This was something that was difficult to manage on the Janvier reducing machine. The modern Micron cutting machines are supposed to prevent this by automatically stepping the cutting tools.)
These have been regularly seen on cents and nickles, but rarely on half dollars. Cool find.