surface finish requirements for aerospace parts. Get instant Radial Engagement (%), Max Step-over (mm) for your machining parameters.
Let our engineers find the right factory for your specs. 100% Quality Guaranteed.
Request a Proposal βWhat does a bad number cost you? Let's run the math on a typical job shop scenario. If your Step Milling is 15% too aggressive, you're not just buying more Sumitomo Electric end mills β you're paying for unexpected downtime, rework, and missed delivery dates.
| Premature OSG tool failures | $6,400/yr |
| Unplanned machine downtime | $12,200/yr |
| Rework / scrap parts | $8,700/yr |
| Excess Rego-Fix holder wear | $2,100/yr |
| Total Annual Loss | $29,400/yr |
Now flip the scenario. By optimizing Step Milling β using the manufacturer's recommended starting parameters for your specific Sumitomo Electric or OSG tool, verified on a Mitutoyo presetter β you could recover nearly $30K annually. That's a new DMG Mori tool probe or a year's worth of Sumitomo Electric inserts.
The ROI is immediate. First part optimized, first day of savings.
Radial engagement (step-over) determines how much of the tool diameter is engaged in the cut. Excessive radial engagement overloads the tool and causes vibration, while too little engagement causes rubbing and poor productivity.
40-70% for most steels with carbide end mills. Below 40% is inefficient (too many passes). Above 80% approaches slotting conditions and should use reduced feed. Aluminium can tolerate 60-80% at high feed rates.
Step-over is the primary determinant of cusp height in 3D surface machining. For ball mills: cusp height = step-overΒ² / (8 Γ tool radius). Halving the step-over reduces cusp height by 75%. For flat end mills, step-over has minimal effect on floor finish.
Scallop (cusp) height is the ridge left between adjacent tool passes. It is determined by step-over and tool nose radius. CAM software typically lets you specify maximum scallop height; it then calculates the required step-over automatically.
Enter your tool diameter and radial width of cut (step-over). The calculator shows the engagement percentage and the recommended maximum step-over. For roughing, keep engagement at 40-70%; for finishing, use much smaller step-overs.
Continue with closely related tools from the machining calculator library.
Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Explore more precision machining tools and calculators