[TR] drill bits

[Dave1massey at cs.com]

In a message dated 12/18/2008 9:31:40 PM Central Standard Time, 
mdporter at dfn.com writes: 
> The most common mistake made with TiN-coated bits is 
> not using enough pressure.  Allowing such a bit to spin work-hardens to 
> material to be cut and rubs off the coating, and the bit stops cutting.

Good point.  Let me just add that the second most common mistake is too much 
speed.  Speed makes for friction, friction makes heat and heat will de-temper 
the drill bit and it will quickly become dull.

Use a drill press whenever you can.  A drill press turns more slowly than a 
hand drill and the mechanical advantage afforded by the crank wheel means more 
pressure will less exertion.  That and a little lubricant can make you drill 
bits last much longer.

Cheers

Dave Massey
St. Louis