1/4" 2-Flute Down Cut Spiral
The clean-top-edge bit. Down cut geometry shears downward into the workpiece, pressing the surface fibres into the material instead of lifting them — which is what makes it the right choice for veneered plywood, melamine, and figured hardwood where the top face is the face that shows.
Specifications
| Property | Value |
|---|---|
| Cutting diameter | 0.250” |
| Shank diameter | 0.250” |
| Flutes | 2 |
| Cutting length | 1.000” |
| Overall length | 2.500” |
| Geometry | Down cut spiral |
| Corner radius | None — square end |
| Material | Solid carbide |
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.
| Material | RPM | Feed | Chipload | Plunge | Stepdown |
|---|---|---|---|---|---|
| Hard maple / oak | 14,000 | 220 ipm | 0.0079” | 30 ipm | 0.125” |
| Soft maple / walnut / cherry | 14,000 | 240 ipm | 0.0086” | 30 ipm | 0.125” |
| Plywood / veneered sheet | 16,000 | 280 ipm | 0.0088” | 30 ipm | 0.125” |
| MDF / laminate | 16,000 | 300 ipm | 0.0094” | 35 ipm | 0.1875” |
| Softwood / pine | 16,000 | 300 ipm | 0.0094” | 35 ipm | 0.1875” |
| Acrylic / HDPE | 12,000 | 200 ipm | 0.0083” | 25 ipm | 0.0625” |
Stepdowns are roughly half what the same-diameter upcut takes, and that is deliberate — see below.
Bits&Bits publish 16–18k RPM at 150–180 ipm for wood and MDF, which works out to about 0.005” per tooth. That is a sensible number for a machine that cannot feed quickly; the X-Carve Pro can, and its spindle drops to 8,000 rpm, so the figures above run a proper chipload instead.
Notes
Always ramp — never plunge. A down cut bit augers chips downward, so a straight plunge packs the hole beneath the cutter with its own waste and the bit rides on compacted dust. Plunge feeds above are set low as a safety net, but the correct entry is a ramp or a helix.
Chip evacuation is the limiting factor, not cutting force. In a deep slot the chips have nowhere to go, so they pack, heat builds, and the edge burns — which in maple means scorch marks you cannot sand out at depth. Halving the stepdown gives each pass a shallower channel to clear.
Not the bit for deep through-cuts. Use U01 for those and accept the tearout on the top face, or rough with the upcut and take a finishing pass with this one.
Avoid it in acrylic if there is any alternative — melted chips get pressed back into the cut and weld to the wall.
Links
- Machine: X-Carve Pro
- CAM library: Fusion hub library, Human Crafted