This step drill bits are quite different from normal one. It has two relief angles, First one for positive cutting and second one for clearance space cooling, guarantee competely pefect cooling result and extra longer life span.

    Smooth low-heat running

    Special relief angle design can be applied to straight flute type and spiral flute type

    Two relief angles.

    Made by high performance HSS, high wear resistance and long tool life.

    CBN fully ground ensure better and sharper cutting edges

    Grooves oppened wide to allow fast and easy chip removal

    Each steop has constant radially adjusted relief and axially relief

    Contered and drilled in one operation

    118  Degree Split point DIN1412C. little pressure required.

    Modified cutting angle made smooth running and positive cut possible.

Order No.	Size	Steps	Shank Size
STDR-30001	4 - 12mm	5 step	6mm/6.5mm
STDR-30002	4 - 12mm	9 step	6mm/6.5mm
STDR-30003	4 - 20mm	9 step	8mm
STDR-30004	4 - 22mm	10 step	10mm
STDR-30005	4 - 30mm	14 step	10mm
STDR-30006	4 - 39mm	13 step	10mm
STDR-30007	5 - 13mm	5 step	6.35mm
STDR-30008	5 - 25mm	11 step	9.5mm
STDR-30009	5 - 35mm	13 step	12.7mm
STDR-30010	6 - 20mm	8 step	9mm
STDR-30011	6 - 25mm	7 step	10mm
STDR-30012	6 - 32mm	9 step	10mm
STDR-30013	6 - 36mm	11 step	10mm
STDR-30014	6 - 38mm	12 step	10mm
STDR-30015	6 - 40mm	16 step	13mm
STDR-30016	9-36 mm	10 step	12mm