Deep Hole Drilling Equipment: Machine and Tooling Selection

Choosing deep hole drilling equipment is a significant capital decision. The right machine and tooling system must match your production requirements — diameter range, depth ratio, materials, and volume — while fitting your budget and facility constraints.

This guide covers machine types by method, tooling systems, coolant requirements, automation options, and the make-vs-buy decision framework.

Machine Types by Method

Gun Drilling Machines

Machine TypeDiameter RangeDepth RatioTypical Cost
Compact single-spindle1.5–25 mmUp to 100:1$100K–$250K
Production single-spindle3–50 mmUp to 100:1$200K–$500K
Multi-spindle (2–8)3–25 mm per spindleUp to 100:1$300K–$800K
CNC lathe retrofit3–25 mmUp to 40:1$20K–$60K

Key specifications to evaluate:

  • Spindle speed range and power
  • Coolant pressure and volume capacity
  • Whip guide support (for depth > 30:1)
  • Contra-rotation capability (for tight straightness)
  • Number of spindles (for production volume)

BTA Drilling Machines

Machine TypeDiameter RangeDepth RatioTypical Cost
Single-spindle (compact)18–65 mmUp to 100:1$200K–$500K
Single-spindle (production)25–250 mmUp to 100:1$400K–$1M
Large-bore50–500 mmUp to 50:1$1M–$3M
Multi-spindle18–65 mm per spindleUp to 60:1$500K–$1.5M

Key specifications to evaluate:

  • Spindle power (BTA requires high horsepower — ~11 HP per inch of diameter)
  • Coolant volume capacity (100–500+ L/min)
  • Pressure head system and sealing
  • Whip guide support along the tube path
  • Contra-rotation for straightness

Ejector Drilling (DTS) Retrofits

System TypeDiameter RangeDepth RatioTypical Cost
CNC lathe DTS package18–65 mmUp to 60:1$20K–$100K
Machining center DTS package18–50 mmUp to 40:1$30K–$80K
Complete DTS system with boring bar18–200 mmUp to 100:1$50K–$150K

Key specifications to evaluate:

  • Coolant flow rate (minimum for Venturi effect)
  • Coolant swivel pressure rating
  • Boring bar support system
  • Adapter compatibility with your CNC machine

Trepanning Machines

Machine TypeDiameter RangeTypical Cost
BTA/trepanning combination50–500 mm$500K–$1.5M
Dedicated trepanning machine100–1,000+ mm$1M–$3M+

Coolant System Requirements by Method

MethodPressureVolumeFiltrationChip Handling
Gun drillingUp to 140 bar15–120 L/min10–20 µmSimple chip tray
BTA drilling20–60 bar100–500 L/min10–20 µmChip separator required
Ejector drilling20–40 bar80–350 L/min10–20 µmChip separator required
Trepanning20–40 bar150–600 L/min10–20 µmChip separator + core handling

Automation and Integration

Automation LevelDescriptionBest For
ManualOperator loads parts, starts cycle, unloadsPrototype, low volume
Semi-automatedAutomatic feed cycle; manual part handlingMedium production
Fully automatedRobot loading, auto tool change, in-process gaugingHigh-volume production
Integrated cellMultiple machines, conveyor system, central coolantMass production

Tooling Systems

Gun Drilling Tooling

Tool TypeDiameterRegrindsCost
Solid carbide gun drill0.5–12 mm7–10$50–$200
Brazed tip gun drill1–30 mm3–5$80–$300
Indexable tip gun drill16–50 mmNone (index insert)$150–$600

BTA and DTS Tooling

Tool TypeDiameterEdge ChangeCost (Ø40 mm)
Brazed carbide head7–65 mmRegrind (3–5×)$150–$300
Indexable insert head15–300 mmIndex inserts$300–$600
DTS drill head18–200 mmIndex inserts$300–$600
Boring bar (BTA/DTS)Per diameterN/A (long-life)$400–$2,000

Make vs. Buy Decision

FactorFavor In-HouseFavor Outsourcing
Annual hole count> 500/year< 500/year
Hole size consistencyConsistent rangeVaries widely
Lead timeNeed same-day turnaround1–3 weeks acceptable
Capital budgetApprovedLimited
Core competencyDeep hole drilling is core businessOccasional requirement

Cost Comparison

MethodCapital InvestmentPer-Hole Cost (Ø40 mm × 500 mm)
Gun drilling (dedicated)$200K–$500K$12–15
Gun drilling (CNC retrofit)$20K–$60K$15–18
BTA drilling$300K–$1.5M$8–12
Ejector drilling (CNC retrofit)$20K–$100K$10–14
Trepanning$500K–$3M$15–25 (saves core material)
Contract BTA service$0 capital$20–50
VolumeRecommended Setup
1–100 holes/yearContract deep hole drilling service
100–500 holes/yearEjector drilling on existing CNC lathe, or contract
500–2,000 holes/yearSingle-spindle gun drilling or DTS retrofit
2,000–10,000 holes/yearSingle-spindle BTA or multi-spindle gun drilling
10,000+ holes/yearMulti-spindle BTA

Summary

Selecting deep hole drilling equipment requires matching machine capability to your production requirements while carefully evaluating the make-vs-buy tradeoff. For low volumes (under 500 holes/year), contract drilling services or a DTS retrofit on an existing CNC lathe are the most cost-effective options. For medium volumes, single-spindle gun drilling or BTA machines are appropriate. For high-volume production, multi-spindle BTA machines offer the lowest per-hole cost.

For a complete method comparison, see deep hole drilling methods overview. For the decision framework, see how to choose the right method. For a complete overview, visit the drilling methods guide.