On Tue, 12 Aug 2008 05:18:07 -0700 (PDT), Edge
wrote:

I have a Craftsman 19.2 volt drill with a half inch chuck. Many times,
especially while pressing hard into the material being drilled, the
bit slips. No matter how much I tighten the chuck, the bit continues
to slip. Other than replacing the chuck, which isn't worth it, what
can be done? Is there a spray of some sort or something else to
provide a better grip on the bit.

What are you drilling? New or old bits? Are you using the right bits
for the job? Maybe dull bits are your problem.