From a solid unit cube, remove an eighth of a sphere of radius 1, centered at one corner of the cube.

From the opposite corner, do the same.

These scoops will intersect. The remaining shape will have a circular hole.

(1) What is the diameter of this hole?

(2) What is the remaining volume?

Geogebra doesn't like solids, only surfaces, but here's a rendering.

TinkerCad is for 3D printing, so it can also be used for another rendering.