Alpha Black Series 4.0mm Jobber Drill Bit
DRILL FEATURES
Tempered black oxide finish reduces friction between bit and workpiece
118 split point for precision hole starting
Fully ground premium quality M2 HSS
Corrosion resistant finish
Ideal for drilling hard metals (coolant recommended)
Not recommended for soft materials or non-ferrous metals
Available in common metric, imperial and panel/stub sizes.

TECHNICAL DATA
Overall Length 75mm
Flute Length 43mm
Stainless Steel RPM 978
Tool Steel RPM 1467
Cast Iron RPM 1956
Malleable Iron RPM 2200
Medium Carbon Steel RPM 2445
Free Cutting Steel RPM 3442
Alum, Brass, Plastic RPM 4889
Wood RPM 7334
Feed per RPM (mm / rev) .05-.15
Standard pack Qty 10
DRILLING PRACTICE
The flute form, web thickness and split point of the standard Alpha drills are suitable for most materials forming fine chips. For effective drilling, the rigidity of the drilland work piece are most important. The shorter the flute length the more rigid the drill. Long drills must be adequately supported to reduce vibration.
The following are important in drill use :
o Clamp the work piece securely
o Select the correct speed and feed
o Use an appropriate coolant or lubricant
o Ensure the shank is securely held. Aviod using worn drill chucks as the drill may slip during use.
o Regrind the point or replace the drill before it dulls, do not force a worn drill.
o When deep hole drilling, withdraw frequently to clear the chips ( deep holes start at 4X the diameter)
o For stainless steel, manganese and high tensile steels, do not allow the drill to swell as it will cause work-hardening. Use a slower speed and heavier feed for these materials.