The ABCs of Deep Hole Drilling Technology

The ABCs of Deep Hole Drilling Technology

Deep hole drilling is a specialized machining process used to create holes with a length-to-diameter (L/D) ratio exceeding 10, and often up to 200 times the hole diameter. Originally developed prior to World War I for gun barrel manufacturing, the technology has since expanded into 200+ applications across more than 15 industries, including aerospace, defense, automotive, energy, and medical.

Why Deep Hole Drilling?

Conventional drilling techniques struggle to maintain:

• Tool life
• Surface finish
• Hole straightness and roundness
• Effective chip removal

Once a hole's L/D ratio surpasses 10, deep hole drilling becomes essential to meet modern accuracy, quality, and productivity standards.

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Types of Deep Hole Drilling Processes

Gun Drilling

Used for hole diameters between 1 mm to 35 mm, gun drilling uses a long, slender drill with a V-shaped flute. High-pressure coolant is pumped through the drill tube, flushing chips out along the flute to maintain a clean and accurate cut.

BTA Drilling (STS – Single Tube System)

BTA drilling handles larger diameters (12 mm to 250 mm). In this process, coolant is supplied around the outside of the drill tube, and chips are evacuated through the inside. This method supports higher feed rates and productivity in large-bore applications.

Key Output Parameters

Achieving consistent quality in deep hole drilling depends on:

• Hole Straightness: How centered and aligned the drilled hole is throughout its length
• Hole Tolerance: The consistency of the hole diameter along the entire depth
• Surface Finish: The smoothness of the hole’s internal wall, essential in fluid handling systems

These parameters are influenced by the selection of process type, machine design, tool geometry, coolant systems, and overall application setup.

Drilling Configurations

There are three main machine configurations in deep hole drilling. Each has its own set of advantages, selected based on:

• Hole length and diameter
• Material type
• Required accuracy and surface finish
• Production volume

Choosing the right configuration is crucial to achieving reliable results and reducing cycle times.

Advanced Applications and Challenges

Modern industry demands drilling in exotic materials and superalloys, often used in aerospace, oil & gas, and medical components. These materials pose challenges in maintaining:

• Bore quality
• Tool wear resistance
• Chip evacuation
  This requires expert process knowledge, precision machines, and robust tooling systems—all areas where Precihole excels.

Precihole Machine Tools: Your Deep Hole Drilling Partner

With over 30 years of experience, Precihole Machine Tools stands as a leader in deep hole drilling and hole finishing technologies. Headquartered in Thane, India, and with offices in the USA and Europe, Precihole provides complete A-to-Z solutions including:

• Gun Drilling
• BTA / STS Drilling
• Trepanning
• Honing & Lapping
• Pull Boring
• Skiving & Roller Burnishing
• Bottle Boring
• Bottom Forming
• And more

We combine cutting-edge machine design, application engineering, and global support to deliver unmatched value across industries.

Global Presence and Innovation

• 3 manufacturing facilities with 150,000+ sq. ft. floor space
• Products and services exported to 25+ countries and growing
• Strong global alliances and distributor networks
• Active collaboration with tooling partners worldwide
• A robust pipeline of innovative, next-gen products under development

At Precihole, we invest heavily in R&D, constantly evolving our solutions to meet new customer demands and stay ahead of trends in cutting tool technology.

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