Tungsten Carbide Reamers: Achieving Precision Hole Machining with IT6 Tolerance and Ra 0.4μm Surface

1. What is a tungsten carbide reamer?

Tungsten carbide reamers (solid carbide reamers) are multi-edged finishing tools used for micro-cutting of existing holes (after drilling or rough boring) to achieve extremely high dimensional accuracy and surface quality. They are key tools for achieving H7 and H6 tolerance grades.

Performance metrics:

Tolerance levels achievable: IT6–IT8 (H7 is standard capability)

Surface roughness: Ra 0.4–1.6 μm

Diameter accuracy: controllable within ±0.005 mm

Roundness and cylindricity: ≤0.003 mm

2. Types of tungsten carbide reamers

Straight flute reamer : Simple structure, good rigidity, suitable for through holes and general precision (IT7–IT8).

Spiral groove reamer : provides smoother cutting, suitable for blind holes or holes with intermittent cutting, and can improve surface quality (IT6–IT7).

Stepped reamer : processes multiple diameter segments at once, improving efficiency.

Replaceable head reamer : The cutter head can be replaced, reducing costs.

Extended reamers : used for deep holes (L/D > 5), typically requiring internal cooling.

Conclusion

Correct selection of tungsten carbide reamer type and appropriate machining parameters can ensure the achievement of high-precision holes and excellent surface finishes in demanding applications.