4.0mm Jobber Drill Bit Carded - Gold Series

Sheffield GroupSKU: C9LM040



Alpha Gold Series 4.0mm Jobber Drill Bit
When you go to buy a drill bit, what are you needing ? Just a drill ? or do you actually want HOLES?

Rigorous independent testing has proven that the Gold Series Drills outperform other Australian drills on the market by more than 30% - giving you more holes for your dollar in every single drill bit !

M2 HSS Fully ground M2 HSS material increases drill life
Titanium Nitride coating reduces heat and increases lubricity for extended life
135 Degree Split Point cuts faster and reduces wandering
All Gold Series Drills are also available as bulk.


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 1



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 :

  • Clamp the work piece securely
  • Select the correct speed and feed
  • Use an appropriate coolant or lubricant
  • Ensure the shank is securely held. Aviod using worn drill chucks as the drill may slip during use.
  • Regrind the point or replace the drill before it dulls, do not force a worn drill.
  • When deep hole drilling, withdraw frequently to clear the chips ( deep holes start at 4X the diameter)
  • 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.

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