Centre Drills are used with a lathe to centre drill stock for mounting in the lathe.
They are designed to drill a small diameter pilot hole followed by a 60° countersink which provides a bearing surface for the 60° point of the lathe centre.
Centre drills are also used extensively with milling machines to accurately start holes.
The hole locations can be dialled in using the milling machine’s calibrated hand wheels.
The hole is then started using the centre drill.
The large diameter shank on the centre drill holds the drill point right on centre.
Once the hole is started, the centre drill is replaced with a drill of the desired diameter and the finished hole is then drilled.
Long Reach Drills are suitable for all general purpose drilling where extra reach is required.
Long Reach Drills are not designed to drill deep holes.
Maximum hole depth must be less than the flute length (FL) of the drill.
Deep hole drilling requires the use of a Bordo Long Series Drill, Bordo Extra Deep Hole Drill or Bordo Auger Bit depending on the material being drilled.
135° Split Point (crankshaft point)
Split point is self centering reducing the need for end thrust.
The 135° point provides superior performance when drilling harder steel materials.
In most situations it will produce thicker chips minimising work hardening of the cavity.
Faster penetration reduces abrasion and friction along the cutting edges.
Black Finish Drills (also called blue finish) achieve their distinctive colour by steam tempering, a thermal process resulting in a porous tool coating.
This surface helps to keep lubricant on the tool, particularly important on the cutting edges, thus reducing friction and cold welding.
The result is increased tool life.
Black finish tools are generally recommended for ferrous applications where the oxide layer aids chip flow and heat dissipation.
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Bordo Metric Green Band HSS-Co TiN Coated Twist Drills for Carbon Steel.
DIN338
130° split point with two helical flutes with 33 degrees of helix angle.
The machinability of different carbon steels is as varied as their properties. Soft-tough construction steels place a unique set of demands on the tools.
The Green Band Series of drills and taps have been developed specifically for this range of steels.
For machining materials with Hardness < 250 HB : Tensile Strength <900 N/mm2.
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Bordo Metric White Band HSS-Co TiAlN Coated Twist Drills for Cast Iron.
DIN338
118° / 70° DX point with two helical flutes with 33 degrees of helix angle.
A highly abrasive material with damping and thermal conductivity, high strength and resistance to wear. Cast Iron is used extensively for mass produced components.
The White Band Series is designed for this specific purpose. TiAlN coating increases tool surface hardness to 87Rc.
For machining materials with Hardness < 300 HB : Tensile Strength <10900 N/mm2.
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This product has multiple variants. The options may be chosen on the product page