Page 301 - ISCAR(HOLE_MAKING_CATALOG_65)
P. 301

USER GUIDE
                                                                                                                      GUNDRILLS






              Single Flute Gundrill                             Single Flute Solid Carbide Gundrills
              Iscar's gundrill consists of a single-piece carbide head,   Another type of gundrill is made with an integral tip and
              a streamlined shank and a driver through which coolant   shank, made of solid carbide with either a steel or a
              flows to the working end where it is most needed. Chips   carbide driver. These drills are designed for conventional
              are evacuated along the V-shaped external flute.  machines, machining centers and lathes. This style of
                                                                gundrill is available from 0.9-16 mm and can be used on
              Drilling Head                                     various types of materials. It provides superior rigidity and
              The carbide head is tapered on its length to reduce   optimal coolant flow rates. As a result of its rigidity, up to
              friction. The taper angle depends on the type of material   100% higher feed rate can be reached.
              to be drilled. For high precision drilling, the taper should be   When using the small diameter drills, it is crucial to
              reduced to a minimum.                             adhere closely to the recommended drilling parameters.
              Note that when the head is resharpened, the diameter
              of the drill changes, affecting the hole tolerance.  Solid Carbide Gundrill Range
                                                                (with or without brazed steel driver)
              Shank                                                   Drill Diameter      Max. Flute Length
              The cross-section of the shank is V-shaped with          0.9 to 16.00           300 mm
              coolant holes. It is made of hardened steel that is
              highly resistant to twisting. This cross-section
              provides the optimal conditions for twist         Standard Gundrill Head Sharpening Angles
                                                                Subject to the required tolerance, cutting performance
              resistance, coolant flow and chip evacuation.
                                                                and desired chip shape, the following standard sharpening
              Driver                                            angles are recommended (shown in figures 1 and 2).
              The driver ensures the connection between          1 Standard sharpening for 0.9 to 4 mm drill diameters
              the gundrill and the machine tool, (see page 301
              for detailed driver information).

              Advantages
            •  Drilling precision of IT7 to IT9 tolerances can be reached
            •  Excellent straightness and concentricity             30˚
            •  Maintains high precision hole center alignment                            30˚
            •  Surface roughness of R0.4 - R1.6 is easily obtained            15˚
            •  Reboring operations are often unnecessary                       30˚           40˚  35˚
              Carbide Tipped Gundrill Range                                              0.25xD

                    Drill Diameter      Max. Flute Length                            D
                     2.50 to 3.09            1100
                     3.10 to 5.99            2500                2 Standard sharpening for 4 to 32 mm drill diameters
                    6.00 to 11.39            3000
                    11.40 to 40.00           3500
              Overall length=flute length+driver length (see page 303)
                                                                                            12˚     0.3-0.5
                                                                    30˚
                                                                                         20˚
                                                                              12˚
                                                    Driver                                   30˚
                                                                                20˚             25˚
                                                                                         0.25xD
                                                                                     D

                                                                 3 Standard sharpening for 32 to 40 mm drill diameters
                                        Shank







                         Drilling Head                                 20°
                                                                                           12°  0,3/0,5
                                                                        25°
              Iscar’s advanced gundrill technology provides               15°  12°       20°    20°
              superior geometric and dimensional quality for                             D/4 ±0,05 25°
              both deep and shallow drilling. The drills are                        Ø Dh5
              available in the range of 2.5 to 40 mm.           Note: For special or semi-standard gundrills, special geometries will be
                                                                offered to match the application.




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