creating hole in sphere

[golfsferr]

I have created a hollow half sphere and I am trying to cut 5 holes in the surface in top view. I have circles above my sphere surface. I have presspulled I have extruded I have projected and I can't create a hole. Actually I would like to trim out the hole then take the trimmed surface and put it back 2mm lower to create a depression. Obviously I'm a newbie and I would appreciate some help, Thanks.

[leeminardi]

Make sure that your "hollow sphere" is a solid with a finite wall thickness.

Here's a cutaway view of a hollow sphere with a cylinder intersecting it.

Use subtract to remove the cylinder from the sphere.

You can use intersect with a sphere and cylinder to get the plug for the hole.

Using a "trimmed surface and put it back 2mm lower to create a depression" would yield a surface that is not concentric with the sphere's outer surface.  It would be better to create a sphere with a radius of the depression and then use intersect or subtract to make the final solid.

A 2D cutaway view would help to explain what you are trying to create.

[Washingtonn]

You could use three spheres (All with the same center point).

Sphere 1 having the required outside diameter.

Sphere 2 having the required inside "hollow" diameter.

Sphere 3 having the required recess diameter (2mm less that sphere 1).

Create extruded cylinders for your holes and subtract from Sphere 1.

Union Sphere 1 and Sphere 3 to create the recesses (let's call resulting solid Sphere 1).

Slice Sphere 1 as required to get half sphere.

Subtract Sphere 2 from Sphere 1 to get hollowed out half Sphere 1 with recesses.

If you need the recesses perpendicular to the outside surface, the Cylinders ("holes") should pass through the center of the sphere.

[golfsferr]

Thanks folks for the great ideas. I'll focus on both to see if one of the suggestion will fix my error but I have tried the 3 sphere idea. It's the actual trim that just doesn't' work but then all the sudden I try the process again and it will  trim. But then next time it won't, very frustrating. I was wonder if there was a tolerance issue that was off. But thanks again, I will try them both.

[golfsferr]

Now I have 2 surface stuck together I need to separate. Yes I tried the separate function. I probably just did it wrong.