Continuing the discussion from Need Help for chamfer:

I took a slightly different approach. It’s more involved, but I think it might offer more control.

- Sketch a circle with the desired radius of the rounded corner.
- Sketch a line through the center of the circle.
- Sketch a radial line at 45 or 135 degrees.
- Sketch a diagonal rectangle from the center of the circle to the end of the 45 degree radial line.
- Extrude a cube equal to the height of one of the sides of the base.
- Revolve a sphere from the half circle.
- Use the Intersect tool to make the rounded corner.

Now it is just a matter of extruding the square ends out to the desired length, width and height to make one eighth of a cube. Then, using Mirror and Union, make the rest of the object.

Here is a 2 minute video