Designed for 120mm square board, 15mm LED spacing, and 3mm LEDs.
This is a simple jig to put 3mm LEDs into an 8x8 grid for use on a 3D 8x8x8 LED cube. Each hole is 3.4mm to allow a little variance in the LED size and printing quality. They're spaced at 15mm between LED centres.
I printed this at 0.2mm with 25% infill and it worked out well for aligning all the LEDs on a grid.