Pilot Guidance
A standard-length drill is first used to create a short pilot hole, ensuring perfect alignment.
Drills / Extra-length deep-hole
Extra Length Drill Bits
What Are Extra Length Drill Bits and How Do They Work?
Extra length drill bits are specialized tools designed for extreme depth-to-diameter ratios. Operating successfully at these depths requires a strict hole drilling method—typically peck drilling—to clear chips and prevent tool breakage. A high-quality deep hole drill bit maintains rigidity while reaching areas that standard drills simply cannot access.
Deep Engagement
The long drill bit enters the pilot hole to prevent wandering.
Peck Drilling
The machine continuously drives and retracts the tool to evacuate chips.
Coolant Flow
Lubrication floods the deep cavity to cool the cutting edges and flush out debris.
Key Features and Benefits of Deep Hole Drill Bits
Extended Reach
Allows access to extremely deep or blocked cavities safely.
Thick Web Construction
Maximizes rigidity to prevent these long drills from snapping under heavy torque.
Parabolic Flute Options
Wider flutes help extract chips efficiently without needing constant retraction.
Standardized Shanks
Mounts securely in any standard CNC collet or specialized deep hole drilling machine.
Versatile Sizing
Available in micro-diameters up to the largest drill bit dimensions required by heavy industry.
Polished Flutes
Reduces friction so chips can slide out of deep cavities effortlessly.
Extra Length Drill Bits Specifications
| Specification | Range / Details |
|---|---|
| Diameter Range | 1/8 inch to 2+ inches (Custom extra-large diameters available) |
| Overall Length | 6, 12, 18, up to 36+ inches |
| Flute Type | Standard Spiral or Parabolic Spiral |
| Shank Type | Straight, Weldon, or Morse Taper |
| Tolerance | Precision ground to OEM specifications |
| Operation Type | Deep hole boring and recessed access |
Materials and Coatings Available for Extra Length Drill Bits
| Material / Coating | Best For | Key Advantage |
|---|---|---|
| HSS (High-Speed Steel) | Deep holes in mild steel and aluminum. | Offers necessary flexibility to prevent the long tool from snapping. |
| Cobalt (HSS-Co) | Hardened steel and aerospace alloys. | The best choice for extra long drill bits for metal, resisting intense heat. |
| TiAlN Coating | Dry machining and deep cavities. | Protects the cutting edges when coolant struggles to reach the bottom. |
HSS provides flexibility for long tools in mild steel and aluminum, cobalt resists heat in hardened steel and aerospace alloys, and TiAlN protects cutting edges in dry or hard-to-cool deep cavities.
Which Machines Use Extra Length Drill Bits?
CNC Machining Centers
Used with automated peck drilling cycles for precise, deep hole generation.
Deep Hole Drilling Machine
Dedicated machines built explicitly for high-pressure coolant and extreme depth ratios.
Heavy Duty Drill Presses
Provides the vertical stability required for manual deep drilling operations.
Applications and Industries for Long Shank Drill Bits
Engine Blocks
Bores deep oil galleries and coolant passages through solid cast iron or aluminum.
Structural Beams
Utilizes robust extra long drill bits for metal to drill entirely through thick steel H-beams.
Heavy Equipment
Prepares deep cavities for oversized fasteners requiring a big hole drill operation.
Recessed Machining
Reaches past interfering obstacles on complex parts utilizing long shank drill bits.
Frequently Asked Questions About Extra Length Drill Bits
What is the correct hole drilling method for a deep hole drill bit?
The most critical method is peck drilling. This involves advancing the drill a short distance, fully retracting it to clear chips from the flutes, and repeating the process. Without peck drilling, packed chips can snap the tool.
Can I use extra long drill bits for metal in a handheld power drill?
It is highly discouraged. Extra length drill bits are fragile due to their length, and angular movement from a handheld drill can bend and snap the bit, creating a safety hazard. They should be used in a rigid drill press or CNC machining center.
Should I drill a pilot hole first?
Yes. Use a standard-length drill or spotting drill to create a pilot hole first. The long drill bit follows this established path, reducing wandering or deflection during initial contact.
Are there special flute designs for long drills?
Yes. Many deep hole drills use a parabolic flute design. Parabolic flutes are wider and have a faster twist rate, lifting chips out of deep holes more efficiently than standard spirals and reducing the frequency of peck cycles.
What is the largest drill bit Bauron can manufacture in an extra-long format?
The source does not state a maximum custom diameter. Bauron can review extended-length, large-diameter requirements and exact blueprint specifications for high-speed steel or carbide-tipped drills.
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