Doug Hobkirk
12-07-2009, 2:21 PM
This is a mystery to me and I obviously have too much time on my hands. I have spent far more time than is rational. But maybe you also enjoy a mystery.
This drill bit "block" came from a garage clean-out. The block is a piece of hardwood with a metal top, copper I think. I expected it to have a set of holes for number bits and another set for fractional sized bits. But when I examined/tested it, I found there were multiple holes for certain sizes and that not all sizes were there, and they were not entirely positioned by ascending size. Starting at the top row, there are:
3 holes at 7/32
3 for 13/64
6 for 3/16
5 for 11/64
5 for 5/32
6 for 9/64
3 for 1/8
and so on. The above is for the first two rows, and the next 3 rows get VERY small
The final 3 rows are not in sequence. Note the end holes on the bottom 3 rows - the first few holes in the next row are smaller.
There is a sequence of numbers below the bottom row that do not seem to gel with the holes immediately above them - the first two "labels" are "4 32" and "6 32", and both holes are 9/64". The labels continue "8 32", "10 32", "10 24", "12 24", "14 24", and then "14 20" (the 1 is above the 4).
This drill bit "block" came from a garage clean-out. The block is a piece of hardwood with a metal top, copper I think. I expected it to have a set of holes for number bits and another set for fractional sized bits. But when I examined/tested it, I found there were multiple holes for certain sizes and that not all sizes were there, and they were not entirely positioned by ascending size. Starting at the top row, there are:
3 holes at 7/32
3 for 13/64
6 for 3/16
5 for 11/64
5 for 5/32
6 for 9/64
3 for 1/8
and so on. The above is for the first two rows, and the next 3 rows get VERY small
The final 3 rows are not in sequence. Note the end holes on the bottom 3 rows - the first few holes in the next row are smaller.
There is a sequence of numbers below the bottom row that do not seem to gel with the holes immediately above them - the first two "labels" are "4 32" and "6 32", and both holes are 9/64". The labels continue "8 32", "10 32", "10 24", "12 24", "14 24", and then "14 20" (the 1 is above the 4).