Question about this DIY light fixture and grounding
In my opinion, nearly all DIY light fixtures are hazards. However, since ceiling fixtures are rarely touched, they're not so bad.  

If you want to add a grounding conductor, it shouldn't be too difficult.  First find a point on the fixture that will hidden within the canopy, and that is metallic.  Figure out a way to attach a grounding wire to that point.  Using a multimeter or ohmmeter, test the resistance between the end of the grounding wire you've attached, and the point on the fixture where you attached it.  You should have a very low resistance, otherwise you've selected a bad location.

Once you have a solid ground. Leave one probe from your meter attached to the grounding wire, and use the other probe to check the resistance to other exposed metallic parts of the fixture.  If you have a low resistance path to all the exposed metallic points on the fixture, you're done.  If not, you'll have to bridge high resistance sections with wire. For example. If the swivel fittings are nonconductive, you'd have to use a pieces of conductive material as a bridge between the two pipe sections.

Now that you have a low resistance path from the grounding conductor, to all exposed metal parts. You'll simply connect the grounding conductor from the fixture, to the grounding conductor from the ceiling.