Counterbores N with a diameter of 50mm and larger are all made with a driving lip. These sizes should be used in the appropriate type M toolholder.

Dimensions (mm) N, NA & W
Counterbores N, and NA with Ø of 50 mm and larger are all made with a driving lip. These sizes should be used in the appropriate type M toolholder
d: 14.0; d1: 6.0; L: 48.0; L1: 28.0.

Range includes 1xD, 1.5xD and 2xD lengths (ISO Metric threads). Our quality inserts are now supplied in packs of 10 or 50. Other sizes and lengths are available on request, please ask for further information.

HSS multi diameter step drills produce good quality holes in a wide variety of sheet metal, using either a bench drill or light pedestal drilling machine. Manufactured from high speed steel, they offer sound rigidity, strength and stability when machining. Each tool cuts parallel holes in a range of specific sizes and is compatible with materials up to 1/8" (3mm) thick.

Features and Benefits
• High speed steel construction for greater strength, rigidity and stability
• Excellent wear and heat resistance for prolonged tool life
• Cuts parallel holes in sheet metal

Typical Applications
• Drilling
• Sheet metal

Notes
• Available sizes 1-12mm to 6-37mm

Conical Shape.
All sizes are nominal with a 6mm shank unless other wise stated.

Cut Numbers:

Cut 6 - Double Cut.
Crosscut and double cut to improve control and chipbreaks. Manufactured from high grade tungsten carbide for general-purpose use.

Cut 9 - Chipbreaker
Chipbreaker fast stock removal for improved control and reduced chips for use on hard materials, i.e. steel alloy 50RC, 60RC, carbon and cast iron.

Suitable for deburring and polishing of cast iron, cast steel, carbon steel, alloy steel and stainless steel etc.
up to HRC65 hardness.

Please note:
• Work piece and tools should always be steady and well supported.
• Carbide burrs are not suitable for 'milling' large amounts of material, they are for light stock removal and high revolutions 'LOW FEED - HIGH SPEED'.
• Always ensure that at least 70% of the shank length is clamped by the collet or chuck of the tool being used.
• Always ensure that the tool is rated to the recommended operating speed of the burr.