At 02:46 PM 05/08/2010, you wrote:
>Hi all,
>
>I'm going to be using hex standoffs to stack PCBs on top of each
>other. These hex standoffs use M3 screws which I have found to use
>screws 3 mm in diameter. For drilling holes appropriate for these
>screws, I have chosen to use tungsten carbide drill bits. Should I
>select a drill bit exactly 3 mm in diameter (such as this one:
>http://cgi.ebay.ca/Tungsten-Carbide-Multipurpose-Drill-Bit-3mm-/1604398537=
50?cmd=3DViewItem&pt=3DUK_Home_Garden_PowerTools_SM&hash=3Ditem255af5e2b6#h=
t_673wt_913)
>or should I select something slightly larger? The question is: will
>the screw slide through if I use a drill bit exactly 3 mm in diameter?

You should simply refer to the data sheet err.. table:

http://littlemachineshop.com/Reference/TapDrillSizes.pdf

Chris conveniently includes the closest US sizes.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the rewar=
d"
speff@interlog.com             Info for manufacturers: http://www.trexon.co=
m
Embedded software/hardware/analog  Info for designers:  http://www.speff.co=
m



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