HSS Drill Bit Manufacturing & Production Process

End-to-End Quality Control at Jiangsu WRD Tools Co., Ltd.

At our 12,000 m² Danyang manufacturing facility, consistency and micro-tolerance adherence are central to our cutting-tool manufacturing capability. Certified and audited onsite by Intertek, our production line integrates strict metallurgy inspection, centerless cylindrical sizing, multi-stage vacuum heat treatment, and 5-axis CNC flute grinding. Every drill bit engineered for global OEMs conforms strictly to DIN 338, DIN 340, DIN 1897, and ASME standards, guaranteeing exceptional concentricity, self-centering precision, and maximum tool longevity.

Stage 01

Stage 1 Raw material cutting at Jiangsu WRD Tools Co., Ltd.

Production Step 01

Raw Material Inspection & Blank Cutting

Every production batch begins with spectrometer analysis and ultrasonic flaw detection of incoming certified high-speed steel rods, including HSS 4241, M2 (6542), and M35 (5% Cobalt). High-speed automated cold-saw cutting machines slice the calibrated stock into precise blank lengths according to DIN tool shank standards, ensuring burr-free ends and uncompromised internal grain structure.

Steel Grades: M35 Cobalt, M2 (6542), 4241

Length Tolerance: ±0.2 mm

Grain Structure: Homogeneous Metallographic Grade

Application: High-stress metalworking bits

Production Step 02

Centerless Cylindrical Rough Grinding

Cut blanks enter high-throughput centerless grinding lines to achieve exact diameter uniformity and concentricity across the entire cylindrical blank. This critical preparatory stage removes surface oxidation and forms the foundation for perfect shank seating and zero-runout performance in drill chucks and magnetic drill spindles.

Concentricity: ≤ 0.02 mm

Roughness (Ra): ≤ 0.8 μm

Coolant Control: Synthetic oil micro-filtered cycle

Inspection: Digital micrometer batch checking

Stage 02

Stage 2 Rough grinding process at Jiangsu WRD Tools Co., Ltd.

Stage 03

Stage 3 Drill bit tip pre-forming and head sharpening

Production Step 03

Tip Pre-Forming & Head Sharpening

Before undergoing thermal strengthening, the front working tip of the blank is pre-machined and conical head geometry is shaped. Pre-chamfering ensures optimal thermal heat flow during subsequent quenching and eliminates internal stress concentrations that could otherwise cause micro-cracking at the cutting lip.

Head Angle: Pre-machined 118° / 135°

Tooling: Automated multi-spindle form cutters

Stress Relief: Chamfered radius edge preservation

Defect Rate: < 0.05% pre-heat gate

Production Step 04

Controlled Atmosphere Quenching & Triple Tempering

Thermal treating is the core determinant of tool endurance. Pre-formed blanks are heated to precise austenitizing temperatures in modern salt-bath and vacuum atmosphere furnaces, followed by rapid, controlled salt-matrix quenching. Blanks then undergo three successive tempering cycles to convert retained austenite into stable martensite, achieving ideal red hardness (63 to 66 HRC) without brittleness.

Target Hardness: 63–66 HRC (M35: 65–67 HRC)

Hardness Variance: ±0.5 HRC across lot

Furnace Control: Microprocessor multi-zone monitoring

Testing: Rockwell Hardness (HRC) calibration

Stage 04

Stage 4 Bar rod quenching and tempering at Jiangsu WRD Tools Co., Ltd.

Stage 05

Stage 5 CNC groove and spiral flute grinding

Production Step 05

Multi-Axis CNC Spiral Flute Grinding

Hardened blanks are processed through fully automated CNC 5-axis grinding stations. Precision cubic boron nitride (CBN) wheels sculpt the deep spiral flutes with micron-level web taper accuracy. This mirror flute finish drastically reduces friction during heavy-feed chip evacuation, preventing chip welding when drilling tough alloys and stainless steels.

Wheel Technology: Multi-grit CBN diamond profiling

Flute Helix Angle: Standard 28°–35° custom tuned

Web Thickness: Linear proportional taper per DIN

Surface Finish: Mirror Ra ≤ 0.2 μm

Production Step 06

CNC Edge Clearing, Relief Grinding & Split Pointing

In the final precision machining stage, CNC relief grinding creates the cylindrical margin and secondary clearance angle along the body. The drill tip is ground to an exact 135° split point conforming to DIN 1412 Type C specifications. This self-centering geometry eliminates walking on curved surfaces, lowers thrust force by up to 40%, and accelerates penetration speeds in industrial applications.

Point Profile: 135° Split Point (DIN 1412 Type C) / 118°

Lip Height Runout: ≤ 0.015 mm

Surface Treatment: Bright, Amber, Black Oxide, TiN, TiAlN

Drilling Test: 100% batch sample penetration test

Stage 06

Stage 6 CNC edge clear and relief grinding

<< Quality Management >>

Manufacturing Assurance

Every production run adheres strictly to rigorous international standards, ensuring each drill bit that leaves our Danyang facility delivers predictable, professional performance.

Full DIN & ASME Compliance

All twist drill bits, step drills, and annular cutters are built to DIN 338, DIN 340, DIN 1897, and ASME standard dimensions. Strict concentricity and total indicator reading (TIR) limits prevent runout and premature breakage.

Intertek Onsite Audited

Jiangsu WRD Tools Co., Ltd. has undergone comprehensive onsite supplier verification by Intertek Group. Our management system, workshop capacity, testing equipment, and export operations are verified transparently for procurement security.

High-Tech Enterprise R&D

Recognized as a Jiangsu High-Tech Enterprise since 2019, our engineering division continually refines cutting geometries, heat treatment recipes, and PVD coating options to maximize tool life in difficult-to-cut metals.

Drill Bits Production Process