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Long Series Drill Bits

Long Series Drill Bits

Long Series Drill Bits

Long Series Drill Bits (also known as Long HSS Drill Bit, Extra Long Jobber Bit or Deep-Hole Drill Bit) are jobber-style HSS twist drills with a longer flute and shank for deep holes or obstructed access. BNA stocks 63+ of these ex stock from our Brisbane warehouse, covering the full range of diameters, lengths and shank styles that engineers, tradies, manufacturers and DIY users need for everyday drilling tasks. Same-day dispatch on online orders placed before 1pm.

Also known as: Long HSS Drill Bit, Extra Long Jobber Bit, Deep-Hole Drill Bit.

Drill Bit Construction & Materials

Alpha Long Gold Series HSS M2 high-speed steel (same as the standard jobber range), heat-treated to 800-900 HV, finished in the gold series TiN-style coating that lifts surface hardness. Holds up to 600 degrees C operating temperature.

Alpha Long Series Cobalt M35 5% cobalt addition for stainless and hardened workpieces. Same geometry as the Gold Series but with the heat-tolerance for production runs in 304 and 316. Identifiable by the darker tempered colour.

Drive & Use

Same 135-degree split point as the standard jobber range. The geometry is unchanged — just the flute and shank are longer. Drilling technique, RPM and lubrication rules are the same as the standard jobber range.

Drill in stages on deep holes. Withdraw every 25mm-50mm to clear chips and let cutting fluid reach the tip. Forcing a continuous deep cut packs chips into the flute, which loads the drill and snaps the bit.

Pilot holes are mandatory for long-series drilling. The longer the bit, the more flex it has, and the more important a guiding pilot becomes. Use a standard jobber bit for the pilot, then step up to the long series for the through-cut.

Drill press is the preferred tool for accurate long-series drilling. Hand-held cordless drivers will work but the bit can deflect off-axis under load, drilling an angled hole. Clamp the work, set the press table square, drill slowly.

Sizing & Measurements

Diameter range 2mm through 13mm metric, plus 1/16" through 1/2" imperial fractional in 1/64-inch steps.

Length range Overall length 90mm-300mm depending on diameter, roughly twice the standard jobber length. Flute length is approximately 13x the diameter, vs. 9x for standard jobbers.

Shank Plain round shank matching the cutting diameter (up to 13mm). 13mm shanks for sizes from approximately 10mm up, so the same drill press chuck handles the range.

Use long series for hollow structural steel (RHS, SHS) where the bit needs to reach the far wall. Standard jobber length will not clear the near-side flange on most box sections over 100mm.

Also used for deep brackets, recessed pockets in machine castings, and any application where the chuck cannot get close enough to the workpiece for a standard jobber to reach.

Length-to-diameter ratio matters: even with the longer flute, a 2mm long-series bit is more flexible than a 13mm long-series bit. Drilling small holes deep, expect the bit to wander unless guided by a pilot or bushing.

WHY AUSTRALIA TRUSTS BOLT & NUT

With 15+ years selling fasteners and drilling tools online from Brisbane, we hold over 25,000 stock lines and 200 million pieces. 98.75% of online orders placed before 1pm leave same day. Save more as you buy more — we offer up to 13 price breaks plus 3 spend-tier discounts. Read our customer reviews or get in touch if you need help picking the right drill bit, holesaw or set for the job.

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