1940 struck through jefferson nickel 2001-p concentric lathe lines kennedy half dollar 1937-p unc clipped cent with reverse lamination and lamination peel a weird medal, (not an error) but was only 99 cents so bought it also from same vendor as cent
What issues of Kennedy are susceptible to lathe lines? A cool error I've not yet seen. What causes it?
Ken Potter, of CONECA, has stated that he had a conversation with a Philadelphia Mint spokesmen about the occurrence of these coins (K. Potter CONECA website),”…[the Mint Spokesman] suspected that they probably had not polished the die blanks sufficiently to remove all the lathe lines. The lines were created when the die blank was machined from a cylinder of steel according to him and we can presume that if this is accurate, that the hubbing process did not eliminate them completely.” Double Headed 2000-D REV To clarify, dies are made from steel rods called Blanks, in the process of preparation the rods they are lathed into a conical shape of approximately 22°. Apparently, after reaching the desired shape, they are furthered polished to remove evidence of their formation. As hypothesized, the lines were inadequately removed from a number of different dies. After being hubbed, some of the lines remained. To the left is a drawing of a die-blank. As there was no specific documentation of dies for coinage with Lathe Lines available, it was suggested that they be documented. Having acquired or borrowing several others from various collectors, a number of dies have thus been identified labeled with the Date, MM, denomination and listing number (e.g., 1996D #C LL 00#); if it ends with an "R", it is a reverse die; they are numbered 001 and onward by year as identified.
Alternative Theories on What Caused these spiral marks on a coin? ALTERNATIVE THEORY I: 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. The consensus was that these are so-called "lathe lines" made when the end of die stock was machined before the design was impressed. Sounds reasonable; however....consider another idea. Multiple impressions from the hub were required to create a complete working die. 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. 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.) The likely cause comes from post-transfer finishing of the die.
Following its final blow from the hub, the soft steel die required cleanup. This was and remains completely normal. This was done either manually by an engraver using small tools and emery sticks, or mechanically using a rotating lap charged with abrasive. The purpose was to smooth the inevitable remaining defects. If the abrasive was too coarse or contaminated with coarse particles, they would leave concentric arcs over the entire surface. Something like this should have been caught on inspection. (At certain times, cleanup might have been done after hardening of the die – we simply do not have enough U.S. Mint practices information to make a definitive statement. Mint machinists did not routinely interact with commercial workers in the same line of business; the mints thought of themselves as holders of “secure information” of critical importance and did little writing about techniques.)
ALTERNATIVE THEORY II: The arcs are too perfectly concentric and too evenly spaced to have been caused by any hand finishing of the die. The assumption is incorrect that any machining marks on the blank die face will be 100% eradicated by the hubbing process. And even if the die was subjected to some post-transfer marks, those marks would affect the fields differently than the tops of the letters. That the circular marks are consistent up and over fields and devices alike is proof that they originated on the hub or die BEFORE it was hubbed. aving over-struck thousands of coins, I have observed that marks on the host coins will persist to a greater degree than one would think, even after multiple strikes at very high tonnage. Even the subtle difference between a burnished blank and an un-burnished blank is evident after striking. Even a slight difference in planchet surface texture can show through after striking or hubbing. Some early commemorative coins have a different type of lathe lines. Master hubs can have lathe lines if there is some "slop" in the Janvier reduction machine. Here is a US Mint medal with some lathe lines that I believe are from the reduction process. This picture doesn't show them very well, but they are there (across the date area). One characteristic of lathe lines from the reduction process is that the lines tend to trail off of some of the devices (such as corners of letters, etc.). This particular 34mm medal suffered from a rather "fuzzy" reduction which may have used an original 3" medal instead of the usual larger galvano. Note the (lack of) sharpness of the date digits compared to the "D" mint mark (which would have been punched into the die after the hubbing).
Lathe Lines There is not much information about this die error. The most extensive information found so far comes from Jason Cuvelier's ErrorVariety.com where he lists 35 different dates and attributed dies including: 1959-D 1961-D 1964 1964-D, 2 attributed varieties 1985 1988 1989 1990 1991 1993-D 1996-D, by far the most common with 21 attributed varieties 2009-S Type 4 Proof 2010 In addition to Lincoln Cents, lathe lines have been identified on Jefferson Nickels: 1988-D, 2000, 2008 (2), 2008-D (2) Kennedy Halves: 1990, 2001 Most recently in a 1982-P Washington Commemorative Half Dollar
check out ctf error coins selling an ms-65 slabbed 1996-d concentric lathe lines for 695.00 guess paying 4.95 was a good deal?? seems prices are all over the place from 4.00 25.00 to 600+ https://www.ebay.com/itm/233929556999?hash=item367749c407:g:xUYAAOSwUuRgTTCl
