Best Extra Long Drill Bits for Deep-Hole Drilling (2026)
We ranked options by fit and value using bit length, HSS construction, shank type, flute design, and overall suitability for deep-hole drilling
The Verdict
- Best Overall: 27/64" x 18" high speed steel drill bit, extra long DWDDL — Best for balanced performance: 27/64" diameter with HSS construction and extra 18" length for deep-hole work
- Best Value: 19/64 x 18 in high-speed steel extra long drill bit — Best for wear resistance: 19/64" HSS extra-long bit with black-oxide finish for improved corrosion and wear protection
This roundup covers extra long drill bits suited for deep-hole drilling, comparing lengths, materials, and shank compatibility to help you choose the right tool for through-holes and deep bore applications. Selections were chosen for fit and value based on bit length, high-speed steel construction, and common shank styles used in industrial and workshop drills
Top Picks
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1
Best Overall 27/64" x 18" high speed steel drill bit, extra long DWDDL
Best for balanced performance: 27/64" diameter with HSS construction and extra 18" length for deep-hole work
High-speed steel drill bit with extra length for reach. Provides hardness and toughness with lubricity from black oxide coating. Customers note sharpness and long flute length, with mixed durability feedback
- extra-long reach
- black oxide lubricity
- round shank versatility
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2
Best Value 19/64 x 18 in high-speed steel extra long drill bit
Best for wear resistance: 19/64" HSS extra-long bit with black-oxide finish for improved corrosion and wear protection
High-speed steel drill bit with extra length for reach. Features black oxide for lubricity and coolant pockets near the edge; round shank for versatile toolholding. Customers note long flute length but mixed durability and sharpness
- extra-long length
- black oxide lubricity
- round shank versatility
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3
9/16" x 18" high speed steel extra long drill bit
Best for large-diameter deep holes: 9/16" HSS extra-long bit provides robust cutting for bigger bores at 18" reach
High-speed steel drill bit with extra reach for general drilling. Combines hardness and toughness with black oxide finish to reduce friction and help coolant retention near the cutting edge. Customers note sharpness and quality, with mixed durability and accuracy insights
- extra long 18" reach
- black oxide surface for lubricity
- sharp, high-speed steel bit