Next, you sketch the hole with a radius that is 10mm less than the boss.
-
Click Extruded Cut
(Features tab).
-
Select the front face of the circular boss.
-
Click Circle
(Sketch
tab).
-
Move the pointer to the center of the boss.
The pointer changes to indicate that the center of the circle
is coincident with the center of the boss.

-
Drag to create the circle and release the tool.
-
Click Smart Dimension
and set
the diameter of the hole to 50.