Step 1: Find Parts Lying Around
four nuts (appropriate to the screws above),
two big washers,
'ZapGel' (gel cyanoacrylate) and 'zip kicker' (a solidifying accelarent)
a thin piece of metal/plastic that you can drill holes in (I used a lego piece with holes already in it)
two capped nuts (I don't know what these are actually called, see picture),
Step 2: Make a Base
cut the washers to a smaller size if needed (just looks nicer)
super glue two nuts in between the washers. Then use ZapGel to strengthen the bond, use a lot of ZapGel to make sure it's really sturdy.
This is a base that you will use to mount your hand onto a 'helping hands' rod or some other rod on your work bench.
Step 3: Make the Balls of the Ball Joint
I also glued to tops from capped nuts (hack sawed off) onto the top to make a smoother metal half. This is not really necessary.
If you have ball bearing of appropriate size lying around, just ZapGel them to the tops of the screws instead.
Step 4: Make the Socket of the Ball Joint
If you don't have a screw with a flat top (makes it easy to turn by hand) for the center hole, make one:
get a screw, cut off two sides of the head (I used a dremel). This makes a head that's easier to turn by hand.