An 8xD solid carbide drill developed for deeper hole drilling in hardened steel and hardened mold steel. Its reinforced cutting edges, rigid variable-core structure, heat-resistant coating, and internal coolant capability help control cutting heat, evacuate chips, and maintain hole straightness.
The 8xD carbide drill for hardened steel is developed for deeper hole machining where high material hardness, concentrated cutting heat, chip evacuation, edge chipping, drill deflection, and hole straightness are more demanding than in short- and medium-depth drilling.
Compared with 3xD and 5xD carbide drills, an 8xD drill has a longer cutting section and a longer chip evacuation path. When drilling hardened steel, insufficient tool rigidity, unstable coolant delivery, or poor chip control can cause heat accumulation, chip congestion, uneven cutting loads, rapid edge wear, hole deviation, or tool breakage.
This drill is manufactured from imported MG grade 0.8 μm submicron tungsten carbide rods with 10% cobalt content. Combined with a heat-resistant coating, reinforced cutting-edge preparation, optimized drill-point geometry, variable core design, deep-hole flute structure, and internal coolant capability, it supports stable deep-hole drilling in hardened steel and heat-treated steel components.
| Item | Description | Item | Description |
|---|---|---|---|
| Product Name | 8xD Carbide Drill for Hardened Steel | Drill Type | Solid Carbide Drill |
| Hole Depth | 8xD | Application | Deep-hole hardened steel drilling |
| Workpiece Material | Hardened steel, hardened mold steel, tool steel, die steel and heat-treated alloy steel | Carbide Material | Imported MG Grade 0.8 μm Tungsten Carbide |
| Cobalt Content | 10% | Helix Angle | 30° |
| Point Angle | 138.9° | Rake Angle | Application-Specific Geometry |
| Negative Chamfer | Reinforced Edge Chamfer | Core Design | 30–40% Variable Core Diameter |
| Back Taper | 0.8° | Coating | ALTISIXN Wear-Resistant Coating |
| Coating Hardness | 2000–4000 HV | Friction Coefficient | 0.05–0.15 |
| Coolant Type | Internal Coolant / External Coolant Available | Tool Life | Up to 80–100 Meters Under Suitable Machining Conditions |
| Service | Regrinding and Customization Available |
| Drill Diameter (mm) | Flute Length (mm) | Shank Diameter (mm) | Overall Length (mm) | Hole Depth | Coolant Type | Availability |
|---|---|---|---|---|---|---|
| D3.00-D3.30 | 30 | 4 | 70 | 8xD | Internal / External | Standard |
| D3.40-D3.70 | 35.5 | 4 | 75 | 8xD | Internal / External | Standard |
| D3.80-D4.00 | 42 | 4 | 83 | 8xD | Internal / External | Standard |
| D4.10-D5.00 | 50 | 6 | 90 | 8xD | Internal / External | Standard |
| D5.10-D6.00 | 57 | 6 | 97 | 8xD | Internal / External | Standard |
| D6.10-D6.80 | 66 | 8 | 106 | 8xD | Internal / External | Standard |
| D6.90-D8.00 | 76 | 8 | 116 | 8xD | Internal / External | Standard |
| D8.10-D10.0 | 95 | 10 | 139 | 8xD | Internal / External | Standard |
| D10.1-D12.0 | 114 | 12 | 163 | 8xD | Internal / External | Standard |
| D12.1-D14.0 | 133 | 14 | 182 | 8xD | Internal / External | Standard |
| D14.1-D16.0 | 152 | 16 | 204 | 8xD | Internal / External | Standard |
| D16.1-D18.0 | 171 | 18 | 223 | 8xD | Internal / External | Standard |
| D18.1-D20.0 | 190 | 20 | 244 | 8xD | Internal / External | Standard |
Key Features
Made from imported 0.8 μm submicron tungsten carbide with 10% cobalt content for a balanced combination of hardness, toughness, and cutting-edge strength.
The carbide substrate helps support the cutting edges under the continuous thrust forces and concentrated cutting loads generated during deep-hole hardened steel drilling.
The self-developed high-performance coating helps resist cutting heat, abrasive wear, oxidation, and premature coating breakdown during hardened steel machining.
Controlled edge passivation and reinforced edge preparation help reduce micro-chipping while maintaining sufficient cutting sharpness and stable penetration.
The variable core structure improves drill rigidity while maintaining sufficient flute space for chip evacuation.
This reinforced design helps the longer 8xD drill resist bending and deflection, supporting more stable hole straightness under continuous cutting loads.
The optimized flute structure provides a controlled chip evacuation path for deeper hardened steel holes.
Stable chip flow helps reduce chip congestion, chip recutting, torque fluctuations, heat accumulation, and damage to the machined hole surface.
This 8xD carbide drill for hardened steel is suitable for deeper hole machining in CNC machining centers, mold manufacturing, tool and die production, automotive component manufacturing, and precision mechanical machining.
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
8xD means that the drill is designed to produce holes with a depth of up to approximately eight times the drill diameter.
For example, a 6 mm carbide drill can machine a hole approximately 48 mm deep under suitable machining conditions.
Yes. This drill is developed for deeper hole drilling in hardened steel, hardened mold steel, tool steel, die steel, and other heat-treated steel materials within the confirmed hardness range.
A 5xD carbide drill is designed for medium-depth holes and generally provides easier chip evacuation and greater rigidity.
An 8xD drill is intended for deeper holes and requires stronger flute rigidity, more effective internal coolant delivery, improved chip evacuation, and better control of drill deflection and hole straightness.
As hole depth increases, chips must travel a longer distance through the flutes. Cutting heat is also more difficult to remove from the drill point.
Without sufficient rigidity, coolant delivery, and chip evacuation, the drill may experience chip packing, torque fluctuations, edge chipping, hole deviation, or tool breakage.
Internal coolant is strongly recommended for 8xD hardened steel drilling.
It delivers coolant directly to the cutting zone and helps evacuate chips through the longer flute path. This is especially important for blind holes, larger diameters, higher hardness, and continuous batch production.
For a flat, stable workpiece surface, the optimized point geometry may support direct drilling under suitable conditions.
For higher positioning accuracy, inclined surfaces, curved surfaces, rough surfaces, interrupted cuts, or demanding deep-hole applications, a pilot hole produced with a shorter carbide drill is recommended.
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