Dear Adrian,
Every bit of info helps in some way. What confused me for a bit was the fact that you did not go from smallest [5 mm] to largest [8 mm]. But then I noticed that in each group, you went from largest number of examples to smallest.
Best,
Joey
I'm adding the following because I have the information to hand.
I hadn't previously realised that glass bottles had the openings in the neck drilled to tidy up what would have been a less uniform opening left by the blowing process, whether it be free blowing or blowing into a mould. So I can now add all the glass bottles from the Bloch and Markovic collections to my previous figures.
From 550 glass bottles the sizes that occur the most are;
6mm 58 bottles
7mm 53 bottles
6.5mm 42 bottles
8mm 31 bottles
These four sizes account for 33.4% of the total number.
For 469 Jade, quartz, stone etc.
6mm 38 bottles
5mm 28 bottles
7mm 27 bottles
5.5mm 21 bottles
These four sizes account for 24.3% of the total number
Combine all these and there are 1019 bottles.
6mm 96 bottles
7mm 80 bottles
6.5mm 54 bottles
5mm 50 bottles
These sizes account for 27.5% of all the bottles.
As before I don't really know what use this is but it is surprising that the 4 most common sizes correspond to metric sizes and point to some consistency in the manufacture of drill bit sizes although the latter is to be expected.
Regards, Adrian.