<p>I just want to ask if anyone has successfully printed a screw (M3 or M4). Is the printed output usable as a screw? What printer is capable of printing screws? I am using an M3D printer - is there a configuration to successfully print a screw that is usable?</p>

<p>Can anyone share a picture of the best 3D printed screw?</p>

well... it's hard to imagine printing M3 or even M4
I haven't try but I haven't because I'm pretty sure it's not possible (on my printer of course)
but some time ago I've tried M8 which is of course way from your needs
it was printed on 0.1mm layer height
it went ok into the nut without any problems but the strength is not very high I suppose
I know the quality is poor but even such bad photo shows issues