In this project we make M2 T-Nuts which are great for attaching components to Voron 0 3D printers, to 1515 aluminium extrusion or even attach the Voron 0 case using the t-nuts. You can use these 'post build' when you can't slide any M3 nuts into the extrusion slots because the ends are blocked off.
The extrusion gap is 3.3mm so the T-Nuts have only a small amount of plastic to encase the M2 thread, so worth watching the video to print them correctly.
3D print details and STL file are on Printables https://www.printables.com/model/297781-m2-t-nuts-for-voron-01-makerbeam-xl-1515-extrusion
T-Nuts for 1515 extrusion are hard to come by so these plastic versions are a good solution. They're not designed for heavy loads but are good for extra add ons.
More 3D print models at https://www.printables.com/social/258241-maker-mike/models