Here is a model of the gear wheel shown on the bed of my Giant 3D Printer.  The grooves are to take the wires to the lampholders from the central stalk/axle/pipe which hangs from the ceiling rose.  I plan to add a finial to the bottom of the axle below the spokes.  I'm thinking of printing the gear wheel in translucent yellow PETG but that may change.  Also, this is just a start - I have the attachments for the lampholders to add.  The lampholders arrived today so I can sort out the fixings.  5x Offgridtec G9 Lamp Holder DVE and UL Listed with ISOL. Cable Lead Lamp Base Socket LED Halogen CFL

Here is a photo of the lampholder and LED bulb (G9 base).  There are two fixing holes 0.5" apart (12.7mm) a bit bigger than 3mm (probably 1/8" = 3.175mm) so M3 bolts will suffice for fixing (one is shown in the photo).  The LED bulbs are 4W, equivalent to a 40W GLS bulb and 5 of them will give plenty of light.  They are the dimmable variety so I will be able to reduce the light output for watching television.