I need to drill a number of 9/16" holes in 304 stainless steel plates.
 Typical plate is 1/4" thick.  Sometimes we stack them and drill 4 at
a time.  We are using a cobalt drill bit at about 450 rpm and spraying
coolant on it.  This drill press is not equipped for flood cooling. 
Having to resharpen the bit after 4 to 6 holes.  How can we improve
tool life and increase drilling speed?

I?ve read that titanium nitride bits reduce friction and are more wear
resistant (85 Rockwell C Hardness) than cobalt bits (Rockwell is
approximately 65.5 to 67). If you sharpen a titanium bit its
performance will drop because the coating is gone on the tip; however,
you still have the benefit of the titanium coating in the flute of the
bit and on the sides of the bit. Even worn will still perform better
than a standard bit. The end result is that you will still have some
wear with a titanium bit as you would with any bit but even if it
wears down the worn titanium bit will be significantly stronger than a
worn cobalt bit. Making this switch may give you more drillings per
bit.

Does this help?

tutuzdad-ga

Bacon grease is the best.

I have had success drilling 316 marine stainless using just ordinary
bits but with a brown paste I got from a marine repair yard. They gave
me a very small jar of it out of a 1 litre container. I am unable to
give a name for it, but it is commercially available. The small amount
has lasted me over five years for my odd boating repair. A quality
engineering shop should be able to identify the paste.