A 12xD solid carbide deep-hole drill developed for hardened steel and hardened mold steel. Reinforced cutting edges, a rigid deep-hole structure, heat-resistant coating, and internal coolant help control heat, evacuate chips, and maintain stable hole straightness over extended drilling depths.
The 12xD carbide drill for hardened steel is developed for deep-hole machining applications where high material hardness, concentrated cutting heat, long-distance chip evacuation, tool rigidity, edge stability, and hole straightness must be carefully controlled.
Compared with 5xD and 8xD drilling, a 12xD drill has a substantially longer cutting section and chip evacuation path. When drilling hardened steel, insufficient coolant delivery, excessive runout, unstable chip formation, or inadequate tool rigidity can cause heat accumulation, chip congestion, cutting-edge chipping, drill deflection, hole deviation, or sudden tool breakage.
This drill is manufactured from imported MG grade 0.8 μm submicron tungsten carbide rods with 10% cobalt content. Combined with an application-specific heat-resistant coating, reinforced cutting-edge preparation, optimized drill-point geometry, variable-core design, deep-hole flute structure, and through-tool coolant capability, it supports stable deep-hole drilling in hardened steel and heat-treated steel components.
| Item | Description | Item | Description |
|---|---|---|---|
| Product Name | 12xD Carbide Drill for Hardened Steel | Drill Type | Solid Carbide Deep-Hole Drill |
| Hole Depth | 12xD | Application | Deep-hole drilling in hardened steel |
| Workpiece Material | Hardened steel, hardened mold steel, hardened tool steel, die steel and heat-treated alloy steel | Carbide Material | Imported MG Grade 0.8 μm Tungsten Carbide |
| Cobalt Content | 10% | Coating | ALTISIXN Wear-Resistant Coating |
| Passivation Control | ±0.003 mm | Edge Inspection |
|
| Service | Regrinding and Customization Available | Tool Life | Up to 80–150 Meters Under Suitable Machining Conditions |
| Drill Diameter (mm) | Flute Length (mm) | Shank Diameter (mm) | Overall Length (mm) | Hole Depth | Coolant Type | Availability |
|---|---|---|---|---|---|---|
| D3.10-D4.00 | 54 | 4 | 92 | 12xD | Internal / External | Standard |
| D4.10-D4.70 | 64 | 6 | 102 | 12xD | Internal / External | Standard |
| D4.80-D6.00 | 83 | 6 | 121 | 12xD | Internal / External | Standard |
| D6.10-D8.00 | 110 | 8 | 148 | 12xD | Internal / External | Standard |
| D8.10-D10.0 | 138 | 10 | 180 | 12xD | Internal / External | Standard |
| D10.1-D12.0 | 158 | 12 | 206 | 12xD | Internal / External | Standard |
| D12.1-D14.0 | 182 | 14 | 230 | 12xD | Internal / External | Standard |
| D14.0-D16.0 | 208 | 16 | 260 | 12xD | Internal / External | Standard |
| D16.1-D18.0 | 234 | 18 | 285 | 12xD | Internal / External | Standard |
| D18.1-D20.0 | 258 | 20 | 310 | 12xD | Internal / External | Standard |
Key Features
Made from imported MG grade 0.8 μm submicron tungsten carbide with 10% cobalt content.
The fine carbide structure provides a balance of hardness, toughness, and cutting-edge strength, helping the long 12xD drill withstand continuous thrust forces and concentrated cutting loads during hardened steel deep-hole machining.
An application-specific heat-resistant coating helps protect the cutting edges against concentrated cutting temperature, abrasive wear, oxidation, and premature coating breakdown.
Controlled edge preparation strengthens the cutting edge and helps reduce micro-chipping under the higher cutting loads generated by hardened steel.
The reinforced variable-core design improves longitudinal and torsional rigidity while retaining sufficient flute space for chip evacuation.
This balance is especially important for 12xD hardened steel drilling, where the drill must resist deflection over a long cutting length while still providing enough space for chips and coolant to move through the flute.
Accurate entry is critical to maintaining hole straightness over a 12xD drilling depth.
For demanding hardened steel applications, a pilot or guide hole produced with a shorter rigid carbide drill can help establish the initial drilling direction before the 12xD drill enters the workpiece.
This 12xD carbide drill for hardened steel is suitable for deep-hole machining in CNC machining centers, mold and die manufacturing, tooling production, automotive components, hydraulic components, and precision mechanical parts.
Send us your material and hole requirements. Our team will recommend the right drill solution.
Landun CNC Tool is a carbide drill manufacturer focused on precision solid carbide drills and custom carbide drill solutions, supported by advanced grinding, strict inspection, and consistent edge preparation.
Production Facility
Geometry Accuracy Control
Edge Inspection Magnification
Edge Passivation Control
Our carbide drills are ground on German WALTER 5-axis grinding machines for sharp cutting edges, stable accuracy, and smooth drilling performance.
We use WALTER HELICHECK PLUS for contour inspection, keeping profile and radius control within 3 μm for reliable geometric precision.
Each carbide drill is inspected at 300x magnification to check edge quality and avoid chipping or saw-tooth defects before shipment.
Manual drill point honing and automatic rubber-bonded diamond abrasive polishing help improve tool life and control edge consistency within ±0.003 mm.
Common Questions
12xD means that the drill is designed for hole depths of up to approximately twelve times the drill diameter.
For example, a 6 mm carbide drill may be used for a hole approximately 72 mm deep under suitable machining conditions.
At this depth, coolant delivery, chip evacuation, tool rigidity, spindle runout, and hole guidance become much more important than in shorter drilling applications.
Yes. It is developed for deep-hole drilling in hardened steel, hardened mold steel, hardened tool steel, die steel, and other heat-treated steel materials within the confirmed hardness range.
Hardened steel generates high cutting forces and concentrated cutting heat, while the 12xD hole creates a long chip evacuation path.
As drilling depth increases, chips and heat become more difficult to remove. At the same time, the longer drill becomes more sensitive to runout, bending, vibration, and initial positioning errors.
Poor process control may therefore cause edge chipping, chip packing, hole deviation, rapid wear, or sudden drill breakage.
Internal coolant is strongly recommended.
It brings coolant directly to the drill point, controls cutting temperature, lubricates the cutting zone, and helps transport chips through the long 12xD flute.
This is especially important for blind holes, higher hardness, larger diameters, and continuous batch production.
A pilot or guide hole is recommended for many 12xD hardened steel applications.
A shorter, more rigid drill can establish accurate hole position and direction before the long drill begins deep-hole cutting.
The actual pilot-hole requirement should be determined according to drill diameter, workpiece hardness, entry surface, hole tolerance, and machine conditions.
Peck drilling should not be applied automatically.
The suitable drilling cycle depends on drill geometry, chip formation, workpiece hardness, coolant pressure, machine rigidity, and the manufacturer’s recommended process.
Excessive retracting may cause repeated impact, chip re-entry, increased cycle time, or cutting-edge damage.
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