1.Right click on cylinder. Change top radius to 0.5
2.Left click on cylinder, resize to 1.450m x 1.450m x 0.854m. Place at 0.000m x 0.000m x 2.299
3.Pop in a box, and place at 0.000m x 0.000m x 2.425m, subtract from sphere.
4.Select sphere, click on boolean add, and click on cylinder.
5.Select box, and move to 0.000m x 0.000m x -1.060m, and right click over bool add, and uncheck Keep Drill.
6.Subtract box from grenade(sphere).
7.Delete cone(cylinder).
Notes:
The meters(m) sizing can always be replaced with your own.