Several years ago I made a LED spindle light for the mill. While it worked well enough at first, over time I became dissatisfied with the amount of light it produced and the lack of an oil-proof enclosure was making it unreliable. It was time to build a new one and improve upon the original design by sealing the LEDs in epoxy and ramping up the light output with 3 COB halo rings.
The original design used one 12V COB LED Halo ring. This time I'm using three nested Halo rings of 120mm / 110mm / 100mm. Since these lights were originally designed for auto use, they use circuitry to step down the auto's 12V electric supply down to something the LED's can handle. I'll be doing this another way so this circuitry will be removed.
Here I'm driving the LED rings in parallel with a DC bench power supply to find the optimum voltage. By increasing the voltage, you can find a setting were the light output doesn't increase much but the current draw increases rapidly. You want to drive the LEDs at the sweet spot voltage right before that happens.
An inexpensive 12V switching power supply will provide the power. Here I'm setting an adjustable buck converter to reduce the input voltage from the power supply down to 8.3V. I also made a simple housing for the LED rings on the 3D printer. You want to make sure everything is working correctly before the next step.
Now the LED rings are being potted in epoxy for waterproofing. I splurged and bought good potting compound instead of hardware store 30 min epoxy. The hope is that this epoxy will remain clear and after a few months of use it seems to be working well.
And here the light is working on the bench. The buck converter was installed inside a small enclosure with a power switch. The enclosure and spindle light will be attached to the mill with powerful rare earth magnets.
Here's a GIF that does a decent job of showing the spindle light output. The mill already had decent lighting from the sides, but the spindle light takes care of the annoying shadow right under the mill head where all the action occurs.
I've been using this mill light for a few months now and it's still working great.