AAARRRGGGGHHHhh! ! ! ! !
It is always nasty working on finished panels!
Use the hole saw after predrilling the center holes as this will make
centering the hole much easier. If there is a fine blade version, that will
probably work better for the powder coating.
The problem is going to be the powder coating more than anything else as
that stuff will tear nicely as you try to cut it. Heating it up with a hot
air gun or other method to about 400F will allow the cuts to seal.
Finally, yes, indeed, use a lubricant to extend the life of the saw as well
as keep the metal cool.
If the hole saw burrs up the powder coating too much, you may want to go to
a single tooth flycutter to remove the powder coating first. Here again,
having a center hole drilled first will mean that you will be able to do
concenctric work on different drill presses without having to do a lot of
setup work as you can use pins instead of drills for the centering piece for
the hole saw, etc.


--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works evevery time it is tried!