Here is a model of a M19 rotary tool thread which you can use in your remixes to create Dremel attachments.
How to use: subtract this from your base model using any 3D editing app, example with "3D Builder" attached.
How I Designed This
It's been years, but if I'm not mistaken: screw_thread(19,2,55,16,PI/16,0);
Poor man's openscad screw library by aubenc
I enjoy designing minimalist-functional 3D objects.