KY Cutting Tools manufactures China-made Gühring-style (also commonly searched as “Guhring style”) double-margin VHM solid carbide drills for stable, accurate holemaking from 3×D to 25×D. Designed with internal coolant channels, polished flutes, and application-specific cutting geometry, these drills are suitable for production machining where hole straightness, surface quality, and consistent tool life matter.
“Gühring-style” describes a compatible geometry concept requested by customers. KY Cutting Tools is an independent manufacturer and is not affiliated with or endorsed by Gühring KG.
What Does VHM Solid Carbide Mean?
VHM is the German abbreviation for Vollhartmetall, meaning solid carbide. Unlike a carbide-tipped drill, a VHM drill uses a solid carbide body. This provides high rigidity, wear resistance, and dimensional stability for CNC machining at productive cutting parameters.
Our drills are ground from selected carbide rods using precision CNC grinding equipment. Diameter, drilling depth, shank, point geometry, coolant-hole design, surface treatment, and coating can be adapted to the customer’s workpiece material and machine conditions.
Why Use a Double-Margin Drill?
A conventional two-flute drill normally has one guiding margin on each land. A double-margin drill adds a second guiding contact area behind the primary margin. The additional guidance can help stabilize the drill inside the hole, particularly when straightness, roundness, and repeatability are important.
- Improved guidance: four guiding margins support smoother rotation inside the bore.
- Stable hole quality: the geometry can help control hole straightness and roundness in suitable applications.
- Reduced vibration: additional support can improve running stability when the setup is rigid and runout is controlled.
- Consistent production: stable guidance supports repeatable results from hole to hole.
Double margins are not a substitute for correct setup. Toolholder condition, spindle accuracy, coolant supply, workpiece clamping, and cutting data remain critical—especially at long drilling depths.
Available Drilling Depths: 3×D to 25×D
The depth ratio compares drilling depth with drill diameter. For example, a 10×D drill with a 6 mm diameter is designed for a nominal drilling depth of approximately 60 mm, subject to the tool drawing and usable flute length.
| Depth range | Typical selection priority | Application notes |
|---|---|---|
| 3×D–5×D | Rigidity and productivity | Suitable for general production holes with external or internal coolant, depending on the application |
| 7×D–12×D | Guidance and chip evacuation | Internal coolant becomes increasingly valuable |
| 15×D–20×D | Deep-hole process stability | A pilot hole and controlled entry strategy may be required |
| 25×D | Coolant delivery and straightness | Use a dedicated deep-hole cycle, suitable pilot tool, and verified coolant pressure and flow |
For 15×D and deeper drilling, the process should be planned as a deep-hole application rather than treated as ordinary short-hole drilling. The machine, pilot hole, coolant system, tool entry, and chip evacuation method must work together.
Internal Coolant for Deep-Hole Drilling
Through-tool coolant delivers fluid directly to the cutting zone. It helps control heat and pushes chips back through the flutes. This is especially important as the depth-to-diameter ratio increases and external coolant can no longer reach the drill point effectively.
Coolant pressure alone does not define a successful process. Flow volume, drill diameter, coolant-hole size, filtration, viscosity, and the available chip space must also be considered. KY can recommend a coolant-channel design after reviewing the application details.
Mirror-Polished Flutes for Chip Evacuation
The pictured drills use polished flute surfaces to reduce chip adhesion and friction. Smooth flute surfaces are particularly useful with long-chipping materials, where welded material or chip packing can damage the cutting edge and hole wall.
Flute polishing is combined with an appropriate helix, flute cross-section, point geometry, edge preparation, and coating. No single feature should be evaluated independently from the complete drill design.
Workpiece Materials and Coating Options
Double-margin solid carbide drills can be engineered for carbon steel, alloy steel, stainless steel, cast iron, and selected non-ferrous materials. The same geometry is not ideal for every material group, so we adjust cutting-edge geometry, carbide grade, flute finish, and coating to match the application.
- TiAlN, AlTiN, TiSiN, and other PVD coating options
- Bright or selectively polished surfaces when appropriate
- Material-specific point and edge preparation
- Standard or customized coolant-hole configurations
- Straight shanks with controlled shank tolerance
Standard and Custom Manufacturing
KY Cutting Tools can manufacture standard-length drills as well as custom diameters, step drills, special overall lengths, and application-specific point forms. Low-volume custom production is available for customers who need to validate a geometry before committing to a larger batch.
Each design should be based on the actual hole requirement rather than only nominal diameter and depth. For a reliable quotation, provide:
- Workpiece material, grade, hardness, and condition
- Hole diameter, depth, tolerance, and surface requirement
- Blind or through hole, including entry and exit conditions
- Machine spindle, holder, and available runout
- Coolant type, pressure, flow, and filtration
- Required coating and expected batch quantity
- Current cutting data and failure mode, if replacing an existing drill
Recommended Setup for 15×D–25×D Drills
- Use the recommended pilot drill to create a stable, accurately positioned entry hole.
- Check spindle and holder runout before machining.
- Enter the pilot hole at the tool supplier’s recommended reduced speed.
- Activate through-tool coolant and confirm adequate flow.
- Apply the recommended cutting speed and feed only after the drill is safely guided.
- Avoid unnecessary dwell or rubbing, especially in work-hardening materials.
- Retract using the specified sequence and inspect chip shape, tool wear, and hole quality.
Final cutting parameters must be selected for the exact drill diameter, material, coating, depth, coolant system, and machine condition. Contact our engineering team for application-specific starting data.
Request a Double-Margin VHM Drill Quotation
If you need a China-made alternative based on Gühring-style double-margin geometry, send us your tool drawing or application details. We can review standard and custom solid carbide drills, including coolant-through deep-hole drills from 3×D to 25×D.
