William, Having just answered your post, It will probably come up in my future, but here goes. In the past there were times that they hand turned screws, and there threads differed. The biggest concern was plate lag bolts that could not have as good a grip if the threads differed. Having said that, today it is becoming less often we find pianos this old, and if it is action screws: well it doesn't have to do with so much stress. Just what I have heard. William PIANO BOUTIQUE William Benjamin The tuner alone, Preserves the tone.
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