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Hardened Steel Milling

Choose an end mill for hardened steel by the measured hardness, steel grade and feature you need to machine. MSU’s MH range offers square, ball-nose and corner-radius end forms for different part geometries.

MH families are listed for material below 65 HRC. The starting data on this page covers 50, 55 and 60 HRC under specified contour-finishing conditions; it is not a parameter table for the whole hardness range.

Share the steel grade, measured HRC, part feature and current setup so MSU can help assess the tool choice.

Get Hardened Steel Selection Help

Match the Tool to the Material and Cut

Hardness is one part of the selection. Steel grade, heat-treatment condition, the required feature and how the tool engages the material all need to match the proposed cut.

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  • Material condition: identify the steel grade, heat treatment and measured HRC. For general or pre-hardened steel, compare Steel & Pre-Hardened Steel Milling.
  • Machining stage: distinguish roughing, semi-finishing and finishing. The starting table below is for contour finishing, so it should not be treated as roughing data.
  • Part geometry: match the end form, diameter, radius and usable reach to the floor, wall or curved feature on the drawing.
  • Engagement: identify axial depth, radial width, stock allowance and whether the toolpath creates interrupted loading. Compare these with the conditions attached to the starting table.
  • Setup: check the holder, overhang, workholding, runout and coolant or air method. Keep the assembly as short as access permits.
  • An existing machining problem: include the current tool, speed, feed and photographs of wear or the part result. These details help distinguish a tool-selection question from a setup or cutting-condition question.

Match the cutting end to the floor, shoulder or curved surface you need to machine.

Compare MH End Forms

Starting Data for Contour Finishing

The values below are MH series starting points for contour machining (finishing), Ap = 0.1 D and Ae = 0.02 D. They apply to the stated hardened-and-tempered steel conditions.

Cutter diameters are 4, 6, 8, 10, 12 and 16 mm, in that order. Each fz sequence follows the same diameter order and is stated in mm/tooth. Vc is in m/min; D is cutter diameter, Ap is axial depth and Ae is radial width.

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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

Read one condition and diameter together. Do not combine a speed range from one hardness row with feed values from another. These are series-level starting values: select and adjust them for the exact MHE4, MHB2 or MHR4 tool, engagement and setup.

Above 60 HRC: request separate starting conditions for the exact material, hardness and tool. The listed MH material range below 65 HRC does not extend the numeric table beyond its three rows.

Before a trial, confirm the grade, measured hardness, tool geometry, allowance, engagement, toolpath, machine rigidity, holder, runout, overhang, workholding and coolant. Begin conservatively, then check tool wear, part dimensions and finish under those conditions.

For related selection principles, see the End Mill Selection Guide and End Mill Coating Guide.

Include the tool code, overhang, speed, feed and engagement, along with any wear, chipping or finish problem.

Ask About Your Cutting Conditions

Check the Tool and Trial Result

A suitable tool needs to meet both the drawing and the machining conditions. Check the complete model and evaluate the result under the conditions you will actually use.

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Before the Trial

Confirm the diameter, end form, radius, cutting length and reach against the drawing. Record the steel grade and measured hardness, along with the starting speed, feed and engagement.

During the Comparison

Assess wear or chipping, part dimensions and surface finish against the same acceptance requirements. If a change is needed, record the tool and cutting conditions with the result so the comparison remains meaningful.

Manufacturing and Inspection

MSU offers these carbide end mills. Explore the manufacturing facilities and discuss inspection requirements for your tool. Specify the critical characteristics and any required inspection records with your enquiry.

The current end mill catalog provides product codes and dimensions for checking the selected configuration.

Use the complete MH model code to check dimensions before ordering or planning a trial.

View End Mill Catalogs

Standard Sizes or a Custom Requirement

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Standard MH Tools

A standard MH tool is an option when its end form, diameter, cutting length, reach and corner radius match the job. Include the complete model code and quantity when requesting a quotation.

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Custom Dimensions and Geometry

If you need a nonstandard dimension or geometry, use Custom Cutting Tools support. Send a dimensioned drawing with the critical tolerances, material, hardness and operation. Substrate, coating, flute count, helix and other requested changes are assessed together before manufacturability is confirmed.

MOQ is normally 5–10 pieces, confirmed by product and quotation. Samples are chargeable, and sample freight is paid by the customer. Completion of the whole order is guaranteed within 25–30 days from order placement; transport time and arrival are confirmed separately.

T/T, deposit and balance stages, shipping terms and packaging are confirmed in the quotation or order. See Ordering and Delivery for purchasing details.

If a standard MH size cannot reach or produce the feature, send a drawing showing the required geometry and critical tolerances.

Discuss a Custom Tool

Hardened Steel Milling Questions

What hardness information is needed?

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

Can I use the published starting data at 64 HRC?

The MH family range is listed below 65 HRC, but this table only contains 50, 55 and 60 HRC rows. For 64 HRC, request starting conditions for the exact grade, tool and setup rather than reusing the 60 HRC row.

Can I apply these values to roughing or slotting?

The table is for contour finishing at Ap = 0.1 D and Ae = 0.02 D. Roughing, slotting or a different engagement needs separate cutting-condition selection.

Do MHE4, MHB2 and MHR4 use the table without adjustment?

No. These are MH series starting values. The end form, complete model, engagement and machine setup must be considered before a trial.

How do I choose the end form?

Use a square end for a flat-end requirement, a ball nose for curved geometry, or a corner-radius tool for a flat end with a defined radius. Check the drawing and toolpath.

Does a suitable hardness range guarantee tool life or finish?

No. Hardness is one condition. Tool geometry, material, engagement, setup and the actual trial result determine whether the process meets your part requirements.

Can I request a nonstandard MH tool?

Yes. Send the drawing, material and hardness, operation, quantity, critical tolerances and inspection requirements. The requested combination is assessed before feasibility is confirmed.