Zruncho's No-Drop Nut mod is very popular but only works for conventional 1515 extrusions, these have been redesigned for makerbeam XL extrusions.
There are 12 and 15 mm (15 mm is best for most uses) single nut versions as well as a double nut version with 15 mm spacing. More versions and parametric CAD will be added later.
They should be printed with the nut side face down with ABS recommended if you ever plan to enclose your printer. When printed on a well tuned printer they should fit snuggly enough to not slip when in a vertical extrusion, if they are too loose or tight you can increase or decrease flow ratio slightly to compensate. Due to the limitations on in channel width you will not be able to screw much beyond the end of the nuts.
The author remixed this model.
Redesigned for makerbeam XL extrusions.