I have a couple of single LED lamps mounted on the front arms of my Mendel, but i wanted more light, and an adjustable source.

I designed this thing. It bolts onto 8mm bar, and has adjustable elbows, and holds an LED module with 3 LEDs.

I found this LED module at Jaycar.
Jaycar Part Number ZD0473. $3.00 each.
It has 3 LEDs and a resistor on a flexible strip, with adhesive on the back.

It consists of 3 parts.
You need 1xpart1, 2xpart2, and 1xpart3.
You can use more part2's if you want.

I initially had recessed nuts and bolts on the parts because i like how they look, but they didn't work very well. When i moved the lamp, the couplings got tighter or looser, and it needed to adjusted all the time.

Now i have removed the recessed nuts, and i use a bolt and nyloc nut to hold each coupling together. I fit a single M4 washer between the plastic parts to provide consistent friction.
The coupling can be moved repeatedly, without the friction changing, so it can be moved into position and it will stay there. You can adjust the friction by adjusting the tension on the bolt.

I can push the lamp out of the way to do something, the push it back, and it will stay there. I can re-orient the lamp and it stays where i put it, without needing adjustment to the couplings.

Print the parts.
Fit a M4x20 bolt and a nyloc nut through each coupling with an M4 washer between the parts.

Part1 will bolt onto 8mm bar.
Part2 will bolt onto part1.
Extra part2's will bolt onto previous part2's. Use as many as you want.
Part3 will botl onto part2.

Wire the LED module and stick it into the recess in part3.
Connect to 12V and see more.