T-slot 1/4-20 nut

Just make sure you print it in 100 micron resolution, mine works fine using PLA, it doesn't hold a lot of weight so I am not worried about it stripping.

I cut the 2 corners off to allow inserting right into the channel, instead of taking whatever else was attached to the channel. In my case it would be taking half of the printer apart in order to slide the nut in.

Enjoy and let me know if you want to change anything about it, it was just a quick 10 min model so please don't judge :)