Extrude.1 without hiding Extrude.2 (built on surface)

[I think I don't know how to use the software correctly / use the right process to design parts]

https://oi000095844-usw2-academia-ifwe.3dexperience.3ds.com/#notification:5356a7c892e54915b98dbafb261586ad

I want to build two simple parts, let's say a disc on top of a plate, both with an M8 hole through. I created Sketch.1 with the hole->extrude->Extrude.1. Then I selected the surface of Extrude.1->sketch->draw the disc with a hole in the middle that has the same diameter as Sketch.1 (snapped right onto it)->extrude->Extrude.2. 

Now I have two "parts" (really only one part). I don't want to go into an assembly. I want to hide Extrude.2 to only export Extrude.1 as DXF to send to the laser cutter (worked). But when hiding Extrude.1 to export only Extrude.2, that one also gets hidden -- of course, the surfaces and hole diameters are linked! 

What's the better way / process to design these simple parts? A base sketch with all lines as "construction"? 

Thorsten

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