1/4" Plunge Roundover

ID: R01

Type: Roundover

A 1/4” roundover that runs in the CNC, not a hand router. No bearing: the pilot is a ground nose on the bit itself (Whiteside calls it a plunge point), which is what makes it CNC-usable at all — nothing to ride, so the toolpath does the guiding and it can even plunge.

Specifications

Property Value
Radius 0.250”
Large diameter 0.750”
Small diameter (pilot) 0.250”
Shank diameter 0.250”
Cutting length 0.375”
Overall length 1.875”
Geometry Plunge roundover, solid pilot
Material Carbide tipped

Feeds & Speeds

For the X-Carve Pro and its 1.5 kW spindle. These match the presets stored on this tool in the Fusion hub library. Chipload is figured at the rim, the 3/4” top of the arc; engagement on an edge pass is a light quarter-round sliver, so one pass at full profile is the normal cut.

Material RPM Feed Chipload Plunge Stepdown
Hard maple / oak 16,000 100 ipm 0.0031” 30 ipm full profile
Soft maple / walnut / cherry 16,000 120 ipm 0.0038” 30 ipm full profile
Plywood 16,000 130 ipm 0.0041” 35 ipm full profile
MDF / laminate 18,000 150 ipm 0.0042” 40 ipm full profile
Softwood / pine 18,000 150 ipm 0.0042” 40 ipm full profile
Acrylic / HDPE 12,000 80 ipm 0.0033” 20 ipm full profile

Same logic as V01: profiling cuts with light engagement run higher RPM than the chipload method would normally allow, and the programmed feed is a ceiling the machine rarely reaches on a contour full of corners.

Notes

Run it as a 2D Contour along the top edge, depth set so the arc lands tangent to the top face. In the library it’s typed as a radius mill, so Fusion models the full profile (1/4” pilot, 1/4” radius, 3/4” shoulder) and the toolpath comes out right without offset tricks.

The pilot is solid, not a bearing. On the CNC it mostly cuts air below the arc, but wherever it does touch, it touches at spindle speed. Don’t let a toolpath park it against a finished face, and don’t dwell in corners.

Do this after the part is cut free or tabbed, like any finishing pass. The side load is small, but a rounded edge is a visible edge; it deserves the same workholding care as a finish contour.

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