Can some one please help me with drill bit size numbering? I have Googled, but my finds were confusing. Some fitting require hole size in inches, some in mm, ok I can convert those, but others are in Drill Numbers, for example a wall plug may require Drill #10, where can I find these equivalences please? TIA
Drill bit sizes
Jan 16, 2005
6 Replies
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I think he was talking about masonry drills, not the old number-sizes of morse twist drills, to which that table refers.
For masonry drills the following is about right:
No. Dia./mm
--- ---
8 4.5 10 5.5 12 6.5 14 7.0 16 8.0
fixing, 10mm for 10mil frame fixing
-- Paul Barker
Thank you both for taking the trouble to answer. Perhaps you can see why I am confused, how can a No 14 drill in one case be 4.6mm and in the other 7.0mm.
I just halve them for mm. It's always been close enough for me.
Christian.
For the same reason that 30 SWG wire isn't the same size as 30 AWG, even though they're both "30 gauge" - different scales, historical reasons, "not invented here" and the mists of time. Oh, and to confuse the uninitiated :-)
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