Milling know-how
Milling chamfers with a V-bit: rough out first, then chamfer
A small chamfer turns a good part into a finished part: edges feel clean, there are no sharp burrs, and small tear-outs on visible edges disappear along the way. Best of all, the second pass with the V-bit only takes a few minutes.
The trick is splitting the job across two tools. The endmill removes the material (contours, pockets, holes) but cannot put a defined bevel on an edge. The V-bit is unsuitable for roughing, but its tip draws an even 45-degree chamfer along every edge (with a 90-degree bit).
Mill a chamfer directly: to the CNC milling tool →
How to do it in step2gcode
- Upload your STEP or DXF file and select the endmill as the tool (e.g. 6 mm). Configure the operations as usual: contours, pockets, holes.
- Generate the G-code, download it and machine the part completely. For through-cut outer contours, enable holding tabs so the part stays fixed.
- Leave the workpiece clamped and do not change the XY origin on the machine.
- Configure the same model again in step2gcode: now select "V-Bit" as the tool type and enter the angle of your bit (90 degrees is common).
- Enable the "Chamfer" operation and set the chamfer depth (default 1.0 mm). An optional separate depth can be set for holes.
- Download the second program, change the tool, re-zero the Z axis and run the chamfer program.
Calculating the chamfer width in your head
With a 90-degree V-bit the geometry is simple: the chamfer width equals the chamfer depth. 1 mm of depth gives a 1 mm wide chamfer, 0.5 mm a subtle 0.5 mm edge. For most parts in wood or plastic, 0.5 to 1 mm is a good starting point.
The most common tool-change mistake
After switching to the V-bit the tool length is no longer correct: the new tool almost never sticks out of the collet exactly as far as the old one. The XY origin stays valid, but Z must be re-referenced on the same surface as in the first pass. Forget it, and the V-bit either cuts the chamfer too deep or drags it uselessly through the air.