David I have discovered Dissimilar material in some of my turning wood, the worst was a large Sycamore I hauled home from he City wood dump, after some very special word for it, a lot of cussing and a tooth missing from the chainsaw chain I got it into two halfs and some extra very-hard-ware and some canvas that had grown in (someones shelter) I did turn the one halve, still have the other half, not the hard - ware ;-)5 nails and a 6” x 9” walnut hollow form on the lathe😁. As soon as I heard the click I knew what it was, stopped and dug out 5 nails. Going to put the metal detector on the other half 😁.
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