HAVING THE PEN IN LIMITS THE X/Y RANGE, SO AT MAX IT WILL BUMP INTO THE FRAME!This holder is designed to fit on the E3D hotend 30mm fan. I actually used it without the screws it was already a tight fit. There is still some small vertical movement. On the other hand it needs some room to get some pressure on the pen. You have to add something on the Z limit switch to get a proper leveling. I added a small 10x10x20 block on the stage and that does the trick for me. I added the stl the openscad design and the ini file that I used. Al this is still very experimental.