Some of these look nearly as 'bad' as the ones I make, Michael!!
In the mid 16th century section, Do I see one with a left-hand thread?
What really surprises me, is that right-hand thread became so standard so soon.
It is interesting how different shaped files were used to cut the threads on the wood screws...some fine and others a much coarser thread,
Mine turn out very similar, depending on what file is at hand at the time!
I should print this page of to keep as a reference.
Thank you for taking the time to compile this chronology!
Richard.
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