Cutaway imagery of hydraulic connections.
Hello mrjohnjoyce
I don’t know if you were going for a photorealistic look, or not.
You could maybe add a (small) bevel to the edges.
Maybe you noticed, but there is the blender 3d cursor in the last Image.
My question here is:
In the last two Pictures: How do you conect the right- with the middlepart?
This just my personal interest 
Hi Nicolas,
Not photorealistic - stylized informational maybe. … These are screen grabs so I guess I forgot to move the cursor on that bottom one ;).
The middle part is a crimp nut that is crimped on over the piece on the right. Making a single assemble where the nut rotates. That is how you tighten the threads. I hope that makes sense.
Thanks for commenting!
John