Meet the Century Drill & Tool 5/16 in. x 3-3/4 in. L Cobalt Steel Stubby Drill Bit with a Straight Shank—a purpose-built tool engineered for metalworking where space is tight and demanding performance is non-negotiable. This polished cobalt steel bit is designed to punch clean, precise holes in hard metals while delivering lasting durability you can trust on every project.
Why this stubby drill bit stands out
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Stubby, high-rigidity design: With an overall length of 3-3/4 in and a flute length of 2-1/8 in, this bit minimizes deflection and chatter in cramped spaces. The reduced reach means steadier starts and straighter holes, even when you’re working inside engine bays, tool housings, or dense metal assemblies.
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Cobalt steel for tough metal drilling: Built for heat resistance and edge retention, this bit maintains sharpness longer when drilling hard alloys such as stainless steel and other hard metals, delivering consistent hole quality across multiple passes.
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Polished finish for smoother cutting: A refined surface lowers friction and helps evacuate chips more efficiently, reducing clogging and heat buildup during extended drilling sessions.
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Straight shank for universal compatibility: Fits standard drill chucks with reliable bite and alignment, offering straightforward setup without special adapters.
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Carded, single-piece packaging: Ready to inventory and easy to grab when you’re on the job, with no compromise on quality or integrity.
Ideal applications and use cases
- Drilling hard metals in automotive repair, fabrication, and metalworking where space is at a premium—think engine blocks, brackets, and metal enclosures.
- Creating precise pilot holes in stainless steel, alloy steel, cast iron, and other tough materials where a standard bit would struggle or wander.
- Situations that demand a clean, accurate hole with minimal chatter, such as electrical panel work or machine shop assembly.
How to get the best results
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Speed and feed: Match drilling speed to the material’s hardness; start moderate and adjust based on chip formation and temperature.
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Cooling and lubrication: Use light cutting fluid or oil when drilling metals to reduce heat and extend bit life.
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Preparation tips: Center-punch the hole location for precise starting point, and drill a shallow pilot hole if needed to guide the bit in hard metals.
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Maintenance: Keep the flute clean of chips, inspect for dullness after heavy use, and avoid prolonged high-speed drilling without lubrication to prevent edge wear.
What problems this bit helps you solve
- Deflection and wandering in tight spaces that compromise hole accuracy.
- Frustration from chips packing and excessive heat during drilling in confined areas.
Specifications at a glance
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Brand: Century Drill & Tool
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Style: Stubby
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Material: Cobalt steel
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Finish: Polished
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Shank Type: Straight Shank
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Drill Size: 5/16 in
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Overall Length: 3-3/4 in
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Flute Length: 2-1/8 in
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Packaging: Carded
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Quantity: 1
Whether you’re outfitting a professional workshop or stocking up for DIY metal projects, this cobalt steel stubby bit from Century Drill & Tool offers a reliable balance of rigidity, heat resistance, and practicality. It’s a move beyond standard bits for anyone drilling hard metals in tight spaces, delivering precise results with every hole.
