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06-05-2008, 09:48 PM #1
Drill Rod sizes vs. Drill/Reamer sizes
I was making small diameter pins from Drill Rod (not drill blanks) and needed a reamer to fit them so I headed for the MSC Catalog.
It turns out that #10 Drill Rod (W-1, 0-1) is .191", but a #10 Drill or Reamer is .1935, but a #11 Drill or Reamer is .191".
What's up with that?
For some silly reason I thought that #10 Drill Rod would be the same size as a "10 Drill or Reamer!
Upon further investigation, very few of the designated drill rod sizes for wire sizes coincide with designated equivalent drill/reamer sizes. I've checked every catalog I can find, all with the same results. Fractional and Letter sizes all coincide.
Anyone know why that is?
06-06-2008, 07:15 AM #2
A little more research in Machinery's Handbook yielded this:
Drills are sized to ANSI B94.11M-1979,R1987
Fractional and Letter size Drill Rod is apparently sized to the ANSI standard above.
Wire size Drill Rod is sized to Stub's Steel Wire Gage sizes which range from #1 to #80 which is similar in designation to Wire Size drills (1 thru 92?) which are sized to the ANSI Standard above.
Apparently, from what I could find, there are at least six different wire gage standards that all use number designations but have differing decimal sizes.
Makes perfect sense........right?
Must have been an Engineer involved
06-06-2008, 08:07 AM #3
It makes even more sense when you consider that ANSI is American and Stubs is English.