Deep Hole Drilling Methods

Different deep hole drilling methods excel at different hole sizes, depth ratios, and production volumes. Gun drilling achieves the highest precision for small diameters (0.5–40 mm, up to 300:1 L/D). BTA drilling delivers the fastest penetration rates for medium-to-large diameters (20–250 mm, 100:1). Ejector drilling (DTS) offers CNC lathe retrofit flexibility for 18–200 mm holes. Trepanning saves material on large bores above 50 mm. EDM and laser drilling handle unconventional materials. This guide provides a structured decision framework, capabilities comparison tables, and cost analysis to help engineers select the right method for any deep hole drilling application.

How Deep Hole Drilling Methods Compare

The right method depends on four factors: hole diameter, depth ratio, tolerance and surface finish, and production volume. Gun drilling wins on precision and depth for small holes; BTA wins on penetration rate for medium-to-large holes; ejector (DTS) wins on retrofit flexibility when no dedicated machine exists. For unconventional materials such as hardened steels, ceramics, and composites, non-traditional methods like EDM, laser, and abrasive waterjet drilling come into play. The table below summarizes the key capabilities.

Method Selection Core Topics

• Deep hole drilling methods overview — every method explained → Deep Hole Drilling Methods
• Method comparison in detail — side-by-side strengths and limits → Deep Hole Drilling Method Comparison
• Maximum depth ratio by method — how deep each method can go → Deep Hole Drilling Depth Limits
• How to choose the right method → How to Choose a Deep Hole Drilling Method
• Cost comparison across methods → Deep Hole Drilling Cost Comparison
• Cost drivers and RFQ — what drives the quote and how to compare bids → Cost Factors and RFQ Guide
• Trepanning for large bores — core-saving and when it pays off → Trepanning Deep Hole Drilling
• Trepanning vs gun drilling for large bores — when to keep the core → Trepanning vs Gun Drilling
• EDM, laser, and other non-traditional methods → Non-Traditional Drilling Methods
• ECM cross drilling — burr-free intersecting holes → ECM Cross Drilling
• Through-holes vs blind holes — what changes per method → Through vs Blind Holes
• Equipment selection for each method → Deep Hole Drilling Equipment

Which Method Should You Use?

Not sure where to start? Use the method selection guide or the selection calculator to get a recommendation from your hole size and material. For a side-by-side capability comparison, see the method comparison.

Start Here

Begin with the deep hole drilling methods overview, then drill into the method comparison to understand the trade-offs. If you already know your hole size and material, jump straight to the selection guide.