Drill bit sizes
 

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

"Broadback" wrote in message
...
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



http://www.cjseymour.plus.com/mechdata.htm

John Woodison wrote:

http://www.cjseymour.plus.com/mechdata.htm

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

--
Andy

I use 5.5mm for red rawl plugs and 6.5mm for brown. 8mm for 8 mil frame fixing, 10mm for 10mil frame fixing.

Andy Wade wrote:
John Woodison wrote:

http://www.cjseymour.plus.com/mechdata.htm


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

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.

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?

I just halve them for mm. It's always been close enough for me.

Christian.

Broadback wrote:

[...] how can a No 14 drill in one case be 4.6mm and in the
other 7.0mm.

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 :-)

--
Andy