DRILL SELECTION BASICS --

• Carbide tipped drills are especially effective when production drilling abrasive cast irons and non-ferrous alloys.
  
• Carbide tipped coolant drills perform exceptionally well in most steels and all other materials.
  
• The drill is an end cutting tool and as the point angle increases, the cutting edge becomes shorter, reducing corner wear as the cutting shear angle is reduced. Rock River provides two different point angles in most drill types. Select the larger angle for abrasive or tough materials.
  
• Deep holes, in excess of 3 drill diameters -- use coolant feeding drills.
  
• For drilling hardened steels, above Rc35 -- use straight flute die drills or coolant type.
  
• Use shortest tool available for accurate location and longer production runs as rigidity is increased and runout minimized.
  
• Core Drills are very effective for enlarging preformed holes, removing up to 30% of the hole diameter in all materials, including steel.

REAMER SELECTION BASICS --

• Carbide tipped reamers are especially appropriate for close tolerance reaming. Because carbide is extremely resistant to wear, the reamer will produce accurate hole size and smooth finish far longer.
  
• The reamer is used to finish machine a previously formed hole to an exact diameter with a smooth finish. It should not be used to significantly enlarge a hole (max. 5% - depending on material and hardness).
  
• The reamer is an end cutting tool, cutting only on the chamfer's edge at the outside diameter of the preformed hole. The standard 45º chamfer angle provides effective cutting action for most materials.
  
• Standard geometry reamers tend to follow the axis of the existing hole. Misaligned or crooked holes can be straightened by increasing the chamfer angle - sometimes a 180º flat end is very effective. This is a simple modification.
  
• FLUTE AXIAL RELATIONSHIP:
  Straight Flutes - usual general purpose.
  Right Spiral Flutes - tend to bridge interruptions such as key-ways, slots or intersecting holes. Good chip clearing ability for ductile materials and blind holes.
  Left Spiral Flutes - also tends to bridge interruptions. Good for hard cast iron, heat treated steels and other hard materials. Do not use in blind holes.
  
• LENGTH OF CARBIDE - usually partial but full length carbide should be selected for deep holes and abrasive materials.
  
• COOLANT FEEDING:
  Advantages - up to twice conventional feed rates will hold size much longer. Improved hole surface finish. Excellent chip disposal. Lubricates and cools the cutting edge.
  Center Feed for blind holes. Flute Feed for through holes.
  
• EXPANSION REAMERS - Economical for abrasive materials.

COUNTERBORE SELECTION BASICS --

• The counterbore is used to enlarge the end of a preformed hole when a flat bottom is required.
  
• The counterbore is an end cutting tool which utilizes a pilot to align the enlarged hole being machined with the preformed hole.
  
• The three flute counterbore tends to reduce chatter & improve finish.
  
• Many different shank options are available.

END MILL SELECTION BASICS --

• END MILLS have cutting teeth on both end and side, permitting end cutting and peripheral cutting. Center cutting types permit plunge and traverse milling.
  
• CUTTING EDGE: Select sharp edged for faster speeds. Select radial edged for longer tool life.
  
• SHANK DIAMETER: Select largest diameter available to maximize rigidity and minimize axial deflection and chatter.
  
• NUMBER OF FLUTES: Select fewer flutes for milling softer materials at higher speeds and feeds where more chip space is required or when machine horsepower is limited.
  
• Select more flutes for milling tougher materials at reduced speeds and feeds or for increased table feeds using the same cutting speeds.
  
• CUTTING DIAMETER: Select largest practical diameter to maximize rigidity, minimize chatter and improve tool life. If machine spindle speed is limited, the largest practical diameter permits higher cutting speeds.
  
• FLUTE AXIAL RELATIONSHIP: Select straight flutes for usual general purpose.
  Select right spiral flutes for improved cutting action and easier chip removal.
  Select left spiral flutes for use in absorbing impact shock when entering steel workpiece -- maintains constant hold down pressure, and minimizes chatter.
  Select high spiral (15º or more) to dramatically improve cutting action, finish, chip removal and tool life. High spirals distribute impact load more evenly throughout the tool's entire revolution.
  
• COATINGS are especially effective.

SLITTING SAW AND SIDE MILLING CUTTER SELECTION BASICS --

• SLITTING SAWS can be used in deep slotting applications since they have side clearance and side concavity on their carbide tips.
  
• ARBOR DIAMETER: Select largest diameter available to maximize rigidity and minimize deflection. (A 1-1/4" arbor is more than twice as rigid as a 1" arbor.)
  
• CUTTING DIAMETER: Select smallest diameter which permits two teeth to be in contact with the workpiece throughout the tool's entire revolution.
  If horsepower permits higher cutting speeds, but spindle speed is limited, select a larger cutting diameter.
  
• NUMBER OF TEETH: Select coarse teeth for general purpose. Select standard teeth for better finishes.
  
• TYPES OF MILLING: Select conventional milling where setup rigidity is limited. The initial portion of the chip generated is very thin and gradually increases through the cutting cycle. The maximum cutting force is upward at the end of the cutting cycle.
  
• Select climb milling where cutting forces are large and the milling machine and set-up are very strong and rigid. The initial portion of the chip generated is thick and gradually thins through the cutting cycle, producing a better finish. The maximum cutting force is the initial downward thrust at the beginning of the cutting cycle.