I found the popular “Skadis T-Nuts Mounting System for Ikea Skadis Pegboards” from 6d6178 but wanted to have a version for M3 screws. In the original Thing, there are quite some arguments why this will not work.

BUT!

I used threaded inserts with a diameter of 5mm which fit perfectly through the Skadis slots.

The Inserts I used have the following dimensions: M3 X D5.0 X L4.0. I got them here.

After installing the threaded inserts, you might need to trim the melted plastic so that it does not exceed the 5mm width.