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There is another technique for making small rings. Drill hole into coin, put on tapered metal rod..some files work, and then tap the coin edge with a spoon repeatedly. You will see the coin start to flatten and widen. There is a YouTube on this as well.
You making a mountain. As it is NOT wrong to do so. Also just cuz YOU or someone else says it is wrong, does NOT make it wrong for me as I did not make any promises to NOT destroy coins. If someone else thinks its wrong then they should not do so!