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End Mill Selection by Hardness

Hardened Steel Milling

Choose an end mill for hardened steel using the exact workpiece grade, measured hardness and heat-treatment condition. Compare MSU MH square, ball-nose and corner-radius families by complete product code and machining conditions.

The catalog lists MH families for material below 65 HRC. The available starting values cover 50, 55 and 60 HRC under the stated contour-finishing conditions. Select parameters for the exact tool, hardness and setup.

Send the workpiece grade, measured HRC, operation, feature, tool dimensions and setup for technical review.

Request a Hardened Steel Review

Define Your Requirement

Provide the steel grade or specification, heat-treatment condition, measured hardness and hardness scale. Use the measured HRC and material grade to compare MH tools with the Steel & Pre-Hardened Steel Milling range.

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  • Operation and stage Roughing, semi-finishing, finishing or contour finishing.
  • Workpiece requirement Feature, drawing, allowance and required surface or dimensional result.
  • Tool geometry Required end form, diameter, flute length, overall length, reach and corner radius when applicable.
  • Engagement and toolpath Axial and radial engagement, toolpath and whether the cut is continuous or interrupted.
  • Machine setup Machine, spindle, holder, runout, overhang, workholding and coolant or air method.
  • Existing process Current tool, speed, feed, wear or failure pattern when troubleshooting an existing process.

Consider the HRC value together with the material grade, tool geometry, operation and setup.

Confirm the hardness and operation before selecting the MH family and end form.

Compare MH End Mill Families

Selection Factors

The values below are MH series starting points for contour machining (finishing), Ap = 0.1 D and Ae = 0.02 D. Cutter diameters are 4, 6, 8, 10, 12 and 16 mm. Each fz sequence follows that diameter order and is stated in mm/tooth.

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  1. 50 HRC Vc 180-250 m/min
  2. 55 HRC Vc 140-210 m/min
  3. 60 HRC Vc 70-140 m/min
Material Condition Hardness Vc (m/min) fz by listed diameter (mm/tooth)
Hardened steel Hardened and tempered 50 HRC 180-250 0.064, 0.096, 0.128, 0.150, 0.165, 0.190
Hardened steel Hardened and tempered 55 HRC 140-210 0.045, 0.067, 0.090, 0.105, 0.116, 0.133
Hardened steel Hardened and tempered 60 HRC 70-140 0.038, 0.058, 0.077, 0.090, 0.099, 0.114

The MH range covers material below 65 HRC, while the starting table stops at 60 HRC. For material above 60 HRC, request separate starting conditions for the exact grade, hardness and tool.

Before applying any value, confirm the exact product code, end form, material grade, actual hardness, stock condition, allowance, engagement, toolpath, machine rigidity, holder, runout, overhang, workholding and coolant. Start conservatively and validate the result under verified shop conditions. The values do not establish tool life, accuracy, finish or cycle time. Use the End Mill Selection Guide and End Mill Coating Guide to structure the broader geometry and coating review.

Send the measured hardness and complete setup before a starting value is calibrated for a specific MH tool.

Send Hardened Steel Conditions

Catalog and Application Requirements

The MH catalog lists the families and diameter ranges above for material below 65 HRC. The available numeric starting conditions cover 50, 55 and 60 HRC.

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Family scope

MH families are listed for material below 65 HRC, with numeric starting values at 50, 55 and 60 HRC. For higher hardness, provide the exact grade, measured hardness and setup for separate parameter selection.

What the catalog supports

MHE4, MHB2 and MHR4 provide square, ball-nose and corner-radius routes within their stated diameter ranges. The below-65-HRC statement defines the family scope, while the numeric starting rows stop at 60 HRC.

What still requires review

For material below 65 HRC, match the exact MH code to the material, hardness, operation and setup. Tool life, finish, accuracy and productivity need to be assessed in the actual cut. Material above 60 HRC and replacement of an existing tool require separate technical review.

Verification route

Review Factory for MSU manufacturing and Quality Control for inspection requirements. Use Downloads to check the family and complete product code before submitting an inquiry.

Check the current product record and keep the hardness and operating range visible during review.

View End Mill Catalogs

Standard or Custom Options

Use a standard MH product when the end form, diameter, flute length, reach, radius and other dimensions match a current catalog code. The complete product code, not MH alone, should appear on the inquiry or order.

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Standard MH route

Match the end form, diameter, flute length, reach, radius and other dimensions to a current catalog code, then quote the complete product code rather than the MH series name alone.

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Custom route

Use Custom Cutting Tools for a nonstandard diameter, length, reach, end geometry, corner radius, chamfer, flute count, helix, substrate or coating. Submit a dimensioned drawing with critical dimensions and tolerances. MSU assesses the requested combination before confirming feasibility.

MOQ is normally 5-10 pieces and is confirmed by product and quotation. Samples are chargeable, with sample freight paid by the customer. Completion of the whole order is guaranteed within 25–30 days from order placement. T/T, deposit and balance stages, delivery terms and packaging are confirmed in the quotation or order. See Ordering and Delivery for the shared commercial process.

Use the custom route when the standard MH dimensions or geometry cannot satisfy the drawing.

Review Custom Cutting Tools

Hardened Steel Milling Questions

What hardness information should I provide?

Provide the measured hardness and scale, steel grade, heat-treatment condition and available method or measurement report.

Does the MH catalog boundary below 65 HRC guarantee machining at 64 HRC?

The catalog lists MH families for material below 65 HRC, but the starting table stops at 60 HRC. For 64 HRC material, submit the exact grade, operation and setup for separate tool and parameter selection.

Can I use the 60 HRC row for material above 60 HRC?

For material above 60 HRC, submit the exact grade, hardness, operation and setup for separate parameter selection.

Are the published values valid for MHE4, MHB2 and MHR4 without adjustment?

No. They are MH series-level starting points. The product code, end form, engagement and machine conditions must be verified before use.

How do I choose the end form?

Use a square end for features requiring a flat end, a ball nose for curved or contour geometry and a corner-radius tool when a specified tool-end radius is required. Confirm the drawing and toolpath.

Can MSU guarantee tool life or surface finish from the hardness value?

No. Those outcomes depend on the complete material, geometry, tool, engagement, setup and verification conditions.

Can a custom hardened-steel end mill be reviewed?

Yes. Submit the drawing, material and hardness, tool geometry, tolerances, operation, quantity and required inspection documents for feasibility review.