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Selecting the right deep hole drilling machine requires comparing specifications across manufacturers — drilling diameter range, maximum depth, spindle power, speed range, coolant system capacity, and automation capabilities all factor into the decision. This article provides structured comparison data for the major global manufacturers.
Manufacturer Overview
The deep hole drilling machine market includes several established manufacturers offering distinct machine series optimized for different applications. The table below summarizes the product range and key differentiators for each.
| Manufacturer | Country | Core Series | Process Types | Primary Applications |
|---|---|---|---|---|
| TBT (Tiefbohrtechnik) | Germany | ML, B, T, DM, BWP | Gundrill (ELB), BTA, STS | Aerospace, automotive, medical, energy |
| UNISIG | USA | UNI, UNX, USC | Gundrill, BTA | Defense, energy, aerospace, mold |
| Mollart Engineering | UK | Drillsprint, Omnisprint, MD | Gundrill, BTA | Automotive, mold, medical, pellet die |
| Kent CNC | USA | KDH, KPGD, KMGD | Gundrill, BTA | General manufacturing, aerospace, medical |
| Sunnen | USA | SHDD | BTA | Automotive, hydraulics, general |
| Precihole | India | BVN, XYBVN, PMTC | BTA, Gundrill | Automotive, oil & gas, general |
| Everox | Taiwan | ELA, ELB | BTA | General manufacturing, mold |
| Dezhou Precision | China | T2120G, T2150, T2250 | BTA (drill/bore/trepan) | General manufacturing, heavy equipment |
Full-Size Deep Hole Drilling Machines
The following table compares specifications for full-size horizontal deep hole drilling machines capable of handling medium to large diameter workpieces.
| Parameter | TBT ML500 | UNISIG UNI-50BTA | Sunnen SHDD6500 | Precihole BVN180P | Everox ELB | Dezhou T2150 |
|---|---|---|---|---|---|---|
| Min diameter (mm) | 0.8 (gundrill) | 8 | 19 | 19 | 30 | 40 |
| Max diameter (mm) | 80 (BTA solid) | 50 | 127 | 180 | 200 | 120 |
| Max depth (mm) | 7,000 | 3,000 | 6,000 | 20,000 | 11,000 | 16,000 |
| Spindle power (kW) | — | 28 (tool) + 20 (work) | 67 (tool) + 38 (work) | 71 | 75–93 | 37 |
| Spindle speed (rpm) | — | 3,000 (tool), 1,000 (work) | — | 20–1,100 | 50–1,100 | 70–1,200 |
| Coolant flow (L/min) | — | — | 6,245 L tank | 2,000 max | — | 800 |
| Coolant pressure (MPa) | 3.3 (33 bar) | — | — | — | — | 2.5 |
| CNC control | Siemens | Siemens / Fanuc | Beckhoff PLC | Fanuc / Siemens | — | Siemens / Fanuc |
| Automation | Robot ATC | Robot-ready | — | Custom | — | Optional CNC |
Gundrilling Machine Specifications
Gundrilling machines typically handle smaller diameter ranges with higher spindle speeds. The table below compares dedicated and combination gundrilling machines.
| Parameter | TBT ML300-4 | UNISIG UNI-12 | Mollart Drillsprint | Mollart MD1 | Kent KPGD | Kent KMGD |
|---|---|---|---|---|---|---|
| Min diameter (mm) | 4 | 1 | 2 | 5 | — | 1.5 |
| Max diameter (mm) | 20 | 12 | 50 | 32 | — | 150 |
| Max depth (mm) | 1,450 | 1,000 | 2,000 | 1,500 | — | — |
| Spindle power (kW) | 4 per spindle | — | — | 22 | — | 5.6–30 (7.5–40 HP) |
| Spindle speed (rpm) | 1,500 | — | — | 0–6,000 | Up to 30,000 | Up to 10,000 |
| Number of spindles | 4 | 2 or 4 | 1–8 | 1 or 2 | 1 | 1–4 |
| Coolant pressure | 33 bar (HP) | — | HP | HP | — | — |
| Weight (kg) | 13,600 | — | — | 4,100 | — | — |
BTA and Large-Diameter Machine Specifications
BTA machines handle larger diameters and higher material removal rates. The table below focuses on BTA-capable machines.
| Parameter | TBT B3S | UNISIG Large BTA | Sunnen SHDD | Precihole BVN250P | Everox ELB | Dezhou T2250 |
|---|---|---|---|---|---|---|
| Min diameter (mm) | 20 | — | 19 | 19 | 30 | 40 |
| Max diameter (mm) | 200 (solid), 400 (trepan) | 630 | 127 | 250 | 200 | 500 (boring) |
| Max depth (mm) | 15,000 | 20,000 | 6,000 | — | 11,000 | 16,000 |
| Spindle power (kW) | 74 (tool) + 30 (headstock) | — | 67 (tool) + 38 (work) | 115 | 75–93 | 37 |
| Tool head speed (rpm) | — | — | — | 10–700 | 50–1,100 | — |
| Counter-rotation | Yes | — | Yes | — | — | Optional |
| Max depth/diameter ratio | — | 100:1+ | — | — | — | 100:1 |
Multi-Spindle and Special-Purpose Machines
For high-volume production, multi-spindle machines offer simultaneous drilling of multiple holes. Special-purpose machines address niche applications such as pellet die drilling, mold cooling hole drilling, and medical component drilling.
| Parameter | TBT DM 50 (Medical) | Mollart Pellet Die | Mollart Omnisprint | UNISIG UNI-25BTA-4 | Kent KPGD (Micro) |
|---|---|---|---|---|---|
| Process | Gundrill | Gundrill | Gundrill | BTA | Gundrill |
| Number of spindles | 2 | 4–16 | 1–6 | 4 | 1 |
| Min diameter (mm) | 0.6 | 1.6 | 2 | 12 | — |
| Max diameter (mm) | 12 | 12 | 22 | 25 | — |
| Max depth (mm) | — | 150 | 1,000 | 1,500 | — |
| Spindle speed (rpm) | Up to 24,000 | Up to 14,000 | — | 3,000 | Up to 30,000 |
| Spindle power (kW) | — | 4 per spindle | — | 15 | — |
| Key feature | Torque sensing, robot | 3s chip-to-chip | Off-center drilling | High feed rate | Ultra-high speed |
Coolant and Filtration System Comparison
Coolant systems are critical for deep hole drilling — they provide chip evacuation, heat dissipation, and tool lubrication. Coolant pressure, flow rate, and filtration capacity vary significantly by machine size and drilling process.
| Parameter | Gundrill (Typical) | BTA (Typical) | Large BTA (Heavy) |
|---|---|---|---|
| Coolant pressure (MPa) | 3–10 | 1–3 | 1–2.5 |
| Coolant flow (L/min) | 10–230 | 100–800 | Up to 2,000 |
| Tank capacity (L) | 700–1,000 | 2,500–7,500 | Up to 12,000 |
| Filtration type | Paper / cartridge | Magnetic + paper | Magnetic + paper + centrifuge |
| Filtration accuracy (μm) | 10–30 | 20–50 | 20–50 |
| Coolant type | Deep hole drilling oil | Deep hole drilling oil | Deep hole drilling oil |
| Chiller | Optional | Recommended | Required |
Coolant System Specifications by Manufacturer
| Manufacturer / Series | Max Pressure (MPa) | Max Flow (L/min) | Tank Capacity (L) | Filtration |
|---|---|---|---|---|
| TBT ML Series | 3.3 (33 bar) | 230 | 1,000+ | Paper band + magnetic |
| Precihole BVN | — | 2,000 | 12,000 | Magnetic + paper |
| Dezhou T2120G | 2.5 | 400 | — | Paper band |
| Dezhou T2150 | 2.5 | 800 | — | Paper band |
| Sunnen SHDD | — | — | 6,245 | Chiller included |
| Mollart MD | HP (specify) | — | — | Bespoke filtration |
Control Systems and Automation
| Manufacturer | Standard Control | Optional Control | Automation Features |
|---|---|---|---|
| TBT | Siemens S7/Sinumerik | — | Tool changer, robot loading, tool monitoring |
| UNISIG | Siemens / Fanuc | — | Robot-ready, servo loader, auto process interrupt |
| Mollart | GE Fanuc Powermate | — | Gantry, robot, pick-and-place, tool monitoring |
| Kent CNC | Fanuc / Siemens | — | — |
| Sunnen | Beckhoff PLC | — | — |
| Precihole | Fanuc / Siemens | Mitsubishi | Custom automation |
| Everox | Mitsubishi | Fanuc | — |
| Dezhou | PLC standard | Siemens / Fanuc / GSK | — |
Modern deep hole drilling machines increasingly offer Industry 4.0 connectivity, real-time production data collection, tool life monitoring, and predictive maintenance alerts. TBT and Mollart, in particular, emphasize smart manufacturing integration across their product lines.
Selection Guide by Application
Aerospace — High-Precision, Small to Medium Diameter
Recommended manufacturers: TBT ML series, UNISIG UNI series, Mollart Drillsprint
Aerospace components require tight tolerances, high surface finish, and often involve difficult-to-machine materials such as titanium and Inconel. Machines with counter-rotation capability, high spindle speeds, and real-time process monitoring are preferred. TBT's ML300 and ML500 series are widely used for landing gear components, while UNISIG UNI series machines handle hydraulic actuator components.
Automotive — High-Volume Production
Recommended manufacturers: Mollart MD series, UNISIG UNI multi-spindle, TBT ML multi-spindle
Automotive applications demand high throughput for components such as crankshafts, camshafts, transmission shafts, and fuel injection components. Multi-spindle machines with automated loading systems minimize cycle times. Mollart's MD1/MD2 machines and UNISIG's multi-spindle BTA machines offer the production rates required for automotive volumes.
Oil and Gas — Large Diameter, Deep Holes
Recommended manufacturers: TBT B3S, UNISIG Large BTA, Precihole BVN
Oil and gas components such as drill collars, subs, and valve bodies require large-diameter BTA drilling with high material removal rates. Machines with heavy-duty spindles (50+ kW), robust coolant systems (1,500+ L/min), and counter-rotation capability are essential. TBT's B3S and UNISIG's large BTA platform are industry benchmarks.
Mold and Die — Off-Center and Eccentric Drilling
Recommended manufacturers: Mollart Omnisprint, UNISIG UNX series, Kent KMGD
Mold cooling channels require off-center deep hole drilling with precise positioning. Mollart's Omnisprint and UNISIG's UNX series offer multi-axis capability for drilling at programmed coordinates, eliminating the need for manual repositioning. Kent's KMGD multi-spindle machines handle mold plate drilling efficiently.
Medical — Micro Diameter, High Speed
Recommended manufacturers: TBT DM series, Mollart micro drilling, Kent KPGD
Medical device manufacturing demands extremely small diameters (below 6 mm), high spindle speeds (up to 30,000 rpm), and precise depth control. TBT's DM twin-spindle machine and Kent's KPGD micro gundrilling series are specifically designed for this application class.
Heavy Equipment and General Manufacturing
Recommended manufacturers: Dezhou T series, Everox EL series, Precihole BVN
For general manufacturing applications where the initial investment is a key factor, Chinese and Indian manufacturers offer cost-effective alternatives. Dezhou's T2120G/T2150 series and Precihole's BVN series provide reliable BTA drilling capability at a lower price point than European or American equivalents, though typically with fewer automation options.
Approximate Price Range Comparison
| Manufacturer Class | Price Range (USD) | Typical Lead Time | Service Network |
|---|---|---|---|
| European (TBT, Mollart) | $250,000 – $1,500,000 | 6–12 months | Global |
| American (UNISIG, Sunnen, Kent) | $200,000 – $1,200,000 | 4–10 months | Americas, select global |
| Indian (Precihole) | $80,000 – $400,000 | 3–6 months | Asia, Middle East |
| Chinese (Dezhou, Everox) | $50,000 – $300,000 | 2–4 months | Asia, limited global |
Prices are estimates and vary significantly based on configuration, automation level, and optional features. Always request a formal quotation from the manufacturer.
FAQ
Q: Which manufacturer offers the widest drilling diameter range? UNISIG's large BTA platform supports diameters up to 630 mm, while TBT's B3S supports up to 400 mm with trepanning. For gundrilling, TBT's ML series covers from 0.8 mm upward, offering the broadest overall range.
Q: What is the deepest drilling depth commercially available? UNISIG offers deep hole drilling machines capable of reaching 20,000 mm (20 m / 65.5 ft) with their ultra-large BTA platform. Precihole's BVN series offers up to 20,000 mm drilling stroke. TBT's ML700 and B3S reach 15,000 mm.
Q: Which machines offer the highest spindle speed? Kent's KPGD micro gundrilling series reaches 30,000 rpm, and TBT's DM medical series reaches 24,000 rpm. For standard gundrilling, Mollart's pellet die machines run up to 14,000 rpm, and Kent's KMGD reaches 10,000 rpm.
Q: How important is counter-rotation for deep hole drilling? Counter-rotation (rotating the workpiece opposite to the tool) significantly reduces centerline drift in deep holes. UNISIG incorporates counter-rotation as standard on most UNI series machines. TBT and Sunnen also offer counter-rotation capability. For depth-to-diameter ratios above 50:1, counter-rotation is strongly recommended.
Q: What coolant pressure is needed for BTA drilling versus gundrilling? Gundrilling typically requires higher coolant pressure (3–10 MPa) due to smaller chip evacuation passages, while BTA drilling operates at lower pressure (1–3 MPa) but requires significantly higher flow rates. Always verify that the machine's coolant system matches the tooling requirements.
Q: Can the same machine handle both gundrilling and BTA processes? Some machines offer dual-capability. UNISIG's UNI-50BTA, for example, supports rapid changeover between gundrill and BTA tooling in approximately 10 minutes. TBT's ML series can also accommodate both processes. Dedicated machines are generally preferred when production volume justifies separate equipment.
Q: What is the typical accuracy of a deep hole drilling machine? Kent CNC specifies ±0.01 mm positional accuracy for their KDH series. Mollart's Omnisprint B-axis achieves ±6 arc-second repeatability. Gundrilling typically achieves IT8–IT11 tolerance with surface roughness Ra ≤ 3.2 μm. BTA drilling can achieve similar tolerances depending on material and operating parameters.
Q: Which manufacturer is best for small-diameter (micro) deep hole drilling? For diameters below 6 mm, TBT's DM series (down to 0.6 mm, 24,000 rpm), Kent's KPGD series (up to 30,000 rpm), and Mollart's micro drilling machines (down to 0.5 mm) are the leading options. Sugino also offers specialized gun feeders for diameters down to 0.9 mm with 300 mm maximum depth.
Q: What should I look for in a coolant filtration system? Key specifications include filtration accuracy (typically 10–50 μm), flow rate matching the machine's maximum pump output, and tank capacity sufficient for thermal stability. Magnetic separators are effective for ferrous chips, while paper band filters handle non-ferrous materials. For high-volume BTA drilling, centrifuge filtration may be necessary.
Q: How do automation options affect total cost of ownership? Automation (robotic loading, automatic tool changers, process monitoring) can increase initial machine cost by 30–50% but significantly reduces labor cost per part and enables unattended operation. For production volumes above 10,000 parts per year, automated loading typically pays back within 12–24 months.