You’re welcome Ken. I just passed along a tip given to me years ago by a fellow enthusiast. Collectors helping collectors. Community.
@kountryken …sometimes die erosion/deterioration will mimic machine doubling. It depends on where in the life-cycle of the die that the erosion begins. Early erosion may only affect the right or left side of a letter, number or design feature, and you could make an assumption that it is “flat and shelf-like” machine doubling. I have seen this, and it gives one pause to check again to confirm. I have seen this phenomenon on Jefferson nickels. Later in the erosion, both sides could exhibit the erosion. It takes a keen eye, attention to detail and experience to be able to define the difference, and it helps to have something to compare to. You can find a lot of help at the “Worthless Doubling” section of Wexler’s website regarding examples to check against. Hope this is helpful for you…Spark