"Miki" wrote in message
...
Hi guys,

I have a project at work, it involves drilling two .600"
holes into
the backplate of a heatsink and through the fins.

On the first try I plunged a .600" drill into the base
plate. When
the drill was through the base plate and touched the fins,
the fins
wanted to wrap around the drill and tear out of the base
plate.

The heat sinks are large surface area, but the fins are
only about an
inch high. They are joined to the base plate with
nonmetallic
adhesive.

Is there a better way to maintain a clean cut through the
heatsink
fins? They are .050" thick aluminum. Base plate is .250"
thick. I
was thinking of filling the fins with Cerrosafe... don't
know if this
is feasible (e.g. Cerrosafe might just push out of the
fins?)

What are you using to do the drilling? If you have a
mill handy and can use power
downfeed to control the feed rate, you might try an annular
cutter. Jancy or Hougen are common brands. Crank up the
RPM, LIGHT downfeed, plenty of lube/coolant.

I use them a lot in thin and fragile material with good
results. Not as aggressive as a
drill, and much more accurate than a hole saw.

..600 is a rather odd diameter. Can you use 5/8" (.625) or
maybe 15mm (.591)????

Bill