Drilling Holes in Metal: A Tutorial
Drill copper/brass/aluminum(300*)/mild steel(100*)/tool steel(70*)/ect. with HSS or Carbide drill bits. Get an automatic center punch and center drill for starting holes.
Handy Formulas
Spindle Speed=
(3.8X*)/(drill bit diameter in inches)
(3.8=4 for rough calculation ease)
Feed Rate(*for normal twist drills)=
(Chip load(.006?))X(RPM)X2*
Avoiding Broken Drill Bits
-Don't allow chips to jam in the flutes.(Typically encountered on deep holes when the flutes are past the hole opening)
(Drill some, clear chips, repeat.)
-Do not bind or bend the drill bit with side force. Push straight and level.
-Use sharp drill bits.
-Hardened material requires special procedures to drill. Should not have to force the cutting edges into material to get them to cut. If the drill is not cutting: spinning it can dull/overheat drill bit resulting in a break.
-Drilling sheet metal is a pain. Twist drills will grab the sheet metal causing problems. Be Careful.
Removing Broken Drill Bits
Take a look at Peterson's broken drill bit extractors. Make some out of brickstrap and such. Get some small needle nosed pliers with round jaws. Then go buy some of Peterson's.
Don't bother trying to drill out a broken drill bit with a larger drill bit. You'll just dull the larger drill bit and possibly break it too.
Sharpening Drill Bits
Get a bench grinder and learn to sharpen drill bits by hand. You'll save money. Hopefully not enough to justify the cost of the grinder, but the time it will save you buying new drill bits should be worth it.
http://www.youtube.com/results?search_query=sharpen+drill+bits&search_type=
