There’s a variety of ways to add threaded holes to 3D printed objects ... You can buy threaded inserts (see video below) but that means some other piece of hardware to have to stock in your ...

After establishing a pull-out force on PLA using threaded inserts (205 kg) and tapped holes (163 kg), [Stefan] tested parts printed with Prusament Tough Anthracite resin. Un-threaded and tapped ...