MPR Series 22 Degree Solid Carbide Micro Internal Profiling and Boring Bar for Small Bore Machining

The MPR series is designed for precision internal boring, profiling, chamfering, contour turning and shoulder finishing inside small-diameter bores. It is suitable for miniature components and restricted internal features that cannot be reached with conventional indexable boring tools.

The 22-degree profiling geometry provides cutting clearance for internal contouring, chamfering and machining near shoulders. It describes the cutting-head geometry shown in the dimensional drawing and does not indicate a 22-degree threading profile.

Standard MPR models cover actual cutting diameters from Ø0.8 mm to Ø7.9 mm. The available cutting diameter should be checked together with the bore diameter, tip radius, cutting depth and required machining clearance.

Standard tip-radius options include R0.05, R0.10, R0.15 and R0.20 mm. The exact radius options depend on the selected cutting diameter and effective length.

Standard cutting depths range from approximately 0.12 mm to 1.80 mm, while effective lengths range from 3 mm to 30 mm. The maximum cutting depth and available reach depend on the selected MPR model.

Primary applications include carbon steel, alloy steel, stainless steel and copper alloys. Selected pre-hardened steels, steels below approximately 48 HRC, cast iron and titanium alloys can also be machined with a suitable carbide grade, coating and cutting parameters.

No. The MPR series is designed for internal profiling, boring, contour turning and chamfering. For dedicated internal thread machining, select an MIR or MIL micro internal threading bar with the required thread profile and cutting direction.

Select the tool according to the bore diameter, cutting diameter d1, tip radius R, cutting depth Q, effective length L1, shank diameter D and overall length L. The cutting head and relieved neck must have sufficient clearance throughout the programmed toolpath.

Choose the shortest effective length that can safely reach the internal feature. A shorter working length normally provides better rigidity, lower vibration and more stable dimensional accuracy.

Use a smaller tip radius for restricted profiles, small corner requirements and reduced cutting forces. A larger radius provides a stronger cutting edge but requires additional profile clearance and may increase radial cutting force.

Use the largest practical shank diameter, minimize tool overhang and use a rigid precision holder. Verify tool runout, cutting-edge orientation and center height before machining. Start with conservative cutting parameters when using long-reach models.

Incorrect center height changes the effective cutting geometry and may increase cutting force, vibration or dimensional error. The cutting edge should be carefully aligned with the workpiece centerline before production.

Coolant is recommended when appropriate for the workpiece material. Direct the coolant toward the cutting area to control temperature and remove chips from the bore, especially when machining deep or blind internal features.

MPR tools use a profiling-oriented cutting-head geometry for contour turning, chamfering and shoulder machining. MTR tools are primarily designed for conventional small-bore internal turning and diameter finishing. Selection should be based on the required internal feature and toolpath.

Yes. Cutting diameter, tip radius, cutting depth, effective length, shank diameter, overall length, cutting geometry and coating can be customized according to component drawings or reference samples.

Please provide the standard model or component drawing, bore diameter, cutting diameter, tip radius, machining depth, effective length, workpiece material, required quantity and any coating, laser-marking or packaging requirements.

The standard minimum order quantity is 10 pieces. Mixed-model and sample-order requirements can be reviewed according to the selected sizes, required quantity and available stock.

Yes. OEM services can include custom model coding, laser logo marking, branded labels and private-label packaging for cutting-tool distributors and industrial suppliers.

In-stock standard models can normally be dispatched within 1–3 working days after order confirmation. The lead time for customized tools depends on the dimensions, geometry, coating, quantity and production requirements.