Differences in the reed count make for what I would consider being minor varieties. Are there any reed count varieties that are considered to be major?
Several of the Morgan silver dollar reed count varieties usually command a strong premium as does the 1876-CC Fine Reeding Seated Liberty quarter. The 153-count reeded quarter is more common than the normal variety with the standard 113 reeds.
I have a Lincoln cent with a significantly rolled edge. How could this have happened?
It is possible someone tapped the edge with a hammer to create the edge; however, it is more likely that the coin got into the laundry, then got stuck between the rotating and stationary drums in a commercial dryer. By tumbling in the dryer, the rim was altered.
What about the edge on the 1907 Rolled Edge Indian $10 eagle?
The edge on the 1907 Rolled Edge Indian $10 eagle was mass-produced and is a mint-produced variety. The beveled rather than square edge with wire rim as it appears on other Indian $10 eagles is due to the different die surface shape. In hindsight, the term “rolled” popularly assigned to this variety is actually a poor choice of wording.
How is the reeding for the collar for coins produced?
According to the 2013 book From Mine to Mint by Roger W. Burdette, “The Philadelphia Mint used a straight knurl to put reeding in the collar. The bored-out collar was put in the chuck of a lathe and allowed to turn slowly. The knurl was held inside the collar while the latter revolved, thus cutting the grooves which produce raised ridges on the coins. Alignment and accuracy of the first few revolutions of the collar largely determine the quality of the finished collar. Once started the knurl naturally fell into the first grooves cut, and tended to repeat until the reeds had been completed.”
If Burdette is correct, why is there variety to some of the reeding on certain coins?
Under the heading “Knurl Tracking” Burdette says, “However, mechanical tolerances for this work were very stringent and a seemingly trivial difference in inside dimension of the collar, or size of the knurl would result in different reed counts on coins. When a single knurl makes its first revolution and then falls back into the first tooth that it rolled, it was tracking correctly. If the circumference of the part being rolled was not an approximate multiple of the pitch of the knurl, the knurl may land somewhere between the two initial teeth, causing it to start a new row.”
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