Drilling Hole 1" deep in Copper

i am posting to ask for advice on hole size in a block of machined copper.
i don't have my text books with me. i don't remember alloys of copper.
for machining.
1" thick stock fly-cut both sides down to .980.
part size - about 1" x 1" x .980.
then i need a hole through the middle.
that's a long way to drill. the design benefits from having a smaller size hole in there, it's for a heat sink. but a 1/8" diameter through an inch of copper ?
i'm not sure i'd want to ask a machinist to do that. might lose parts to drill breakage, don't want to have to deal with that.
so, what diameter would be most manufacturable ?
thanks !
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Dear wwswimming:

Heat sinks benefit from having short conduction paths and high surface area. A cube has none of this. Its only saving grace will be relatively high heat storage capacity, so short duty cycle.

A drill should be OK. It have seen obsure shapes formed using "electrical discharge machining" (EDM) ... a simple hole should be no problem for EDM.

No, but might "gum up" the flutes.

I don't think it will be as bad as you imagine. Any reason you aren't using one of the thousand or so standard heatsinks?

1/8" not a problem.
David A. Smith
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snipped-for-privacy@yahoo.com wrote:

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On 13 Jul 2006 19:40:55 -0700, in sci.engr.mech snipped-for-privacy@yahoo.com wrote:

We do this all the time in heat sink copper propulsion models at work. Yes so care must be used, or you may need a visit to the edm to remove the bit.
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