CARBIDE TIPPED DRILLS
TECHNICAL INFORMATION
DRILL BASICS
  • Drills are end cutting tools used to produce holes when rapid removal of material is desired
  • Use shortest drill available for accurate hole location
    and minimum runout for maximum tool life
  • Non-coolant fed drills (conventional twist drills) are generally effective in holes up to 3 tool diameters deep. Peck cycles should be used for deeper holes to achieve better chip evacuation
  • Coolant fed drills should be used for production drilling of holes greater than 3 tool diameters deep
  • Coolant fed drills offer higher penetration rates, reduced cycle times, and straighter/rounder holes with better finishes
  • If non-centering drill is used, HANNIBAL recommends using a spotting drill for improved hole location
  • Spotting drill's point angle should be greater than production drill's point angle to prevent edge chipping and to ensure accurate hole location
DRILL SELECTION GUIDE
 TWIST DRILLS - NON-COOLANT
  • Excellent up to 3 tool diameters deep
  • Use shortest length available
  • Excellent in non-ferrous materials and cast irons
  • Generally not recommended for drilling steels (use die drill or coolant drill instead)
  • See drill point selection
DIE DRILLS
  • Excellent in hardened steel 35 to 65 Rockwell C
  • Will cut without annealing the workpiece
  • See drill point selection
COOLANT FED DRILLS - STRAIGHT FLUTES
  • Longer flutes for deep hole drilling
  • Produce straighter holes and better finishes
  • Excellent performance in many materials
  • See drill point selection
COOLANT FED TWIST DRILLS
  • Better chip clearing ability in ductile materials and high density alloys
  • Spiral flutes permit higher feed rates
  • Excellent performance in most materials
  • See drill point selection
CORE DRILLS
  • Used to enlarge cored, punched, or preformed holes
  • Capable of removing up to 30% of tool diameter
  • Produces near-reamed surface finish
  • Often eliminates need for final reaming or boring operation
DRILL SPECIFICATIONS
  • Carbide tip high temperature brazed to hardened tool steel body
  • Smooth flutes for effective chip flow
  • Precision ground to insure concentricity of tip & body
  • Dimension & element tolerances conform to following standard, unless otherwise specified on selected styles: ASME/ANSIB94.11M * ISO * NAS 907 * USCTI
  • "Taper Shank No." refers to American Standard taper series (formerly Morse taper series) per ASME/ANSI B5.10
  • Jobber length & taper length drills 1/2" diameter and smaller are manufactured with an overall length tolerance of +1/4", -1/8"
DRILL TOLERANCES
Tool Diameter Diameter Included Angle Lip Height T.I.V.
Plus Minus Plus Minus
Thru 1/8" .0000" .0005" 5° 5° .0020"
Over 1/8" thru 1/4" .0000" .0007" 5° 5° .0030"
Over 1/4" thru 1/2" .0000" .0010" 5° 5° .0040"
Over 1/2" thru 1" .0000" .0012" 3° 3° .0050"
Over 1" thru 1 1/2 " .0000" .0015" 3° 3° .0060"
 
DRILL PROBLEM SOLVING GUIDE - CARBIDE TIPPED

AVOID PROBLEMS BY CAREFUL ORIGINAL SET-UP
MACHINE CONDITION Tool holder in good condition and secure part holding fixture
TOOL CONDITION Use cutting tool recommended for material being machined. Avoid excessive tool overhang.
FEEDS & SPEEDS Start with feeds and speeds recommended for material being machined
COOLANT Coolant flow must be adequate to avoid intermittent quenching and to flush chips promptly, avoiding the recutting of hardened chips.

DRILLING PROBLEMS POSSIBLE CAUSES POSSIBLE SOLUTIONS
1. CHIPPED CUTTING EDGE Excessive feed Reduce Feed
Excessive lip relief Reduce lip relief to provide smaller chisel angle
Vibration Frequently a worn drill bushing - Replace
Thermal cracking carbide Maintain adequate coolant flow at all times
2. SHORT TOOL LIFE Drill dwelling Maintain adequate feed at all times
Only one lip cutting Regrind with equal lip heights and chisel in center
3. DRILL WALKS OR DRIFTS Unequal lip heights Regrind with equal lip heights and chisel in center
Worn drill bushing Replace drill bushing
4. OVERSIZED HOLES Unequal lip heights Regrind with equal lip heights and chisel in center
Excessive lip relief Reduce lip relief to provide smaller chisel angle
Worn drill bushing Replace drill bushing
5. ROUGH FINISH Dull cutting edge Regrind with fine grit diamond wheel
Inadequate coolant Review type of coolant and maintain adequate flow