I found that when ordering cheap bulk M3 screws, both machine and self tapping, there was a rather large lack of constantly in the exact geometry of them, mostly on lead in and thread relief. This hasn't effected the use of nuts but I have found that it has resulted in some inconsistencies in the hole size I need to design into my parts. To save myself the head ache I have made this part. The hole diameters are listed on the part. I would recommend printing in the settings you intend on using. I would also recommend doing this for every material you are having issues with. In my experience it was not a one size fits in every material.