FEEDER MECHANISM DIE DAMAGE PATTERNS ≈1990 to 2018 I have been studying Feeder Mechanism Die Damage Patterns and the types of Feeder Mechanisms in use at the US Mint in different time periods. Many folks have contributed to my efforts by providing photos of Die Damage for me to include in my Census. I make educational use of some of these photos with credit. I thank everyone for this support and for your insight, advice, and encouragement! I have prepared a series of articles in which I have attempted to organize and summarize my findings into an easy-to-use reference so that the most likely Feeder Mechanism causing a certain die damage pattern may be identified. The information is divided by time periods: · 1896 to 1945 in COINWEEK 2/19/2026 https://coinweek.com/feeder-mechanisms-and-die-damage-patterns-1896-1945/ · 1945 to ≈1990 COINWEEK 3/10/2026 https://coinweek.com/feeder-mechanisms-and-die-damage-patterns-1945-%e2%89%881990/ · ≈1990 to 2018 · 2018 to present The current article in the series for • ≈1990 to 2018 may be found here: COINWEEK 4/2/2026 https://coinweek.com/feeder-mechani...-1990-2018-a-diagnostic-guide-for-collectors/ This is a highly condensed summary of a small section of the research I have been pursuing, periodically, for the last 2+ years.
Very nice presentation. I have looked at a lot of Lincoln cents, and I can recognize some of the different marks on them. It is interesting to see them change. I will be prone to scutinize Linear Plating Blister differently now.
Thank you! I would expect most linear plating blisters to have a rounded profile in cross section compared to feeder scrapes which should show a more squared/rectangular cross-sectional profile. Let me know what you are finding!
I sure wish @Electron John could've stuck around. He would've been able to get you a good profile comparison.
I've got some pretty esoteric gear around the house at this point, but I don't have an electron microscope, and it's pretty far down on the priority list.
GOOD QUESTION! THANK YOU! Damage from the feeder mechanism has been found on both dies and sometimes shows on both sides of the same coin. The feeder mechanism is inserting planchets between both dies while the press is running with a targeted output of 750 coins per minute, so both dies are susceptible to being "in the way" of potential damage if there is the slightest malfunction. I have not run a study (yet) of the frequency on one die or the other. The difficulty of such a study is identifying which die is most likely the anvil or hammer during the time that the mint was converting to an inverted die installation (anvil die as the hammer die). Inverse Die Installation: Initially, the common practice at the mint was to use the obverse die as the hammer die. However, in the 1990s, the mint began experimenting with using the reverse die as the hammer die. By the mid to late 90s, this inverse die installation became the predominant set-up used by the mint. For business strike coins, from 1992 to 2005, the US Mint was converting from vertical stroke Bliss Presses (anvil die = reverse die) to horizontal stroke Schuler Presses (anvil die = obverse die). In both press styles, the anvil die is the stationary die. Since the middle of 2005 all circulation-quality strikes have been struck with inverted dies (reverse die as hammer die).
