Direct Alignment
The ultra-short shank engages the workpiece with zero flex or runout.
Drills / Stub-length tools
Stub Length Drill Bits
What Are Stub Length Drill Bits and How Do They Work?
Stub length drill bits (also known as screw machine drills or stubby drill bits) are short-fluted cutting tools designed to deliver extreme rigidity during hole-making operations. By drastically shortening the distance between the machine chuck and the cutting tip, stub drills eliminate the bending leverage that causes longer drills to wander or snap under heavy feeds.
Self-Centering Entry
Typically equipped with a 135° split point that bites instantly into the material without walking.
High-Feed Shearing
The reinforced thick steel core allows operators to apply aggressive feed pressure safely.
Rapid Evacuation
Compact flutes lift chips out of shallow holes quickly, preventing heat buildup and clogging.
Key Features and Benefits of Stub Length Drill Bits
Maximum Rigidity
Compact profile makes these tools virtually unbreakable during straight plunging operations.
Eliminates Spotting
The short, stiff construction allows you to drill directly into hard metals without starting with a center drill.
Tight Clearance Access
Fits easily into right-angle drill heads and cramped mechanical compartments.
High Feed Efficiency
Thick web cores absorb heavy thrust loads, enabling faster machine cycle times.
Vibration Reduction
Shorter flute spans suppress chatter, improving hole roundness and internal surface finish.
Stub Length Drill Bits Specifications
| Specification | Range / Details |
|---|---|
| Diameter Range | 1/64" to 1" (Standard, Metric, Wire, and Letter sizes) |
| Flute Length Ratio | Compact geometry (approx. 4x to 5x tool diameter) |
| Point Angle | 135° Split Point (Standard self-centering) or 118° |
| Shank Type | Straight Cylindrical |
| Tolerance | Precision ground to exact H7 or OEM specifications |
| Operation Type | High-rigidity and short-reach hole drilling |
Materials and Coatings Available for Stub Length Drill Bits
| Material / Coating | Best For | Key Advantage |
|---|---|---|
| HSS (High-Speed Steel) | Mild steel, brass, aluminum, and plastics. | Highly durable, economical, and resistant to mechanical shock. |
| Cobalt (HSS-Co) | Stainless steel, cast iron, and titanium. | High thermal stability prevents edge dulling under extreme friction. |
| TiAlN Coating | High-speed dry CNC machining. | Reduces friction drastically, extending the cutting edge life across long production runs. |
HSS offers economical shock resistance for general materials, cobalt adds thermal stability for stainless steel and titanium, and TiAlN reduces friction in high-speed dry CNC machining.
Which Machines Use Stub Length Drill Bits?
CNC Lathes / Turning Centers
Mounted in tool turrets for fast, unyielding hole-making along the spindle centerline.
Automatic Screw Machines
The original machinery designed for these compact, heavy-feed cutting tools.
Portable Hand Drills
Mechanics favor stubby drill bits for manual drilling in cramped vehicle compartments due to their unbreakable nature.
Applications and Industries for Stub Drill Bits
Confined Bay Machining
Bores clearance holes in tight automotive engine bays and structural frames where standard jobber bits cannot physically fit.
High-Speed CNC Turning
Utilized in automated CNC lathes and screw machines for rapid, high-feed hole generation.
Hard Material Boring
Penetrates tough stainless steel, titanium, and nickel alloys without the tool flexing or snapping.
Sheet Metal Drilling
Produces round, burr-free holes in thin sheet metal using robust stub drill bits that resist catching.
Frequently Asked Questions About Stub Length Drill Bits
What is the difference between jobber drills and stub length drill bits?
Jobber drills are standard, general-purpose tools with longer flutes designed for deeper hole reaching. Stub length drill bits have much shorter flutes and overall lengths, making them vastly more rigid, less prone to snapping, and ideal for shallow holes or restricted spaces.
Do I need a pilot hole when using stub drills?
No. One of the main advantages of using stub drills with a 135-degree split point is their extreme stiffness. They do not wander or flex upon contact, allowing you to drill directly into solid workpiece surfaces without creating a center or pilot hole first.
Are stubby drill bits good for handheld power drills?
Yes, they are exceptional for handheld power drills. Mechanics and field installers prefer stubby drill bits because their short length allows them to fit into tight spaces, and their rigidity makes them far harder to accidentally snap if the operator tilts the drill slightly.
How deep can I drill with a stub length bit?
Because of their short flute design, these bits are optimized for shallow holes—typically up to 3 to 4 times the drill's diameter. For deeper cavities, you should use a stub drill to start the hole accurately, then transition to a jobber or extra-long bit to finish the depth.
Does Bauron offer custom stub tooling geometries?
Yes. Bauron specializes in custom CNC tools. We can manufacture custom stub length drill bits with specific step profiles, specialized point angles, or custom carbide grades tailored precisely to your automated manufacturing requirements.
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