My railcore has a halo with magnums on the top, and misumi corner brackets on the bottom. So mounting the x endstop on the top or bottom of the extrusion is a pain.

This x endstop mounts on the same side as the linear rail.

Hardware:

• Two M2 screws (for mounting the switch)
• Two M2 nuts (captive in the part)
• Two M3 screws (for mounting to the rail)
• Two M3 nuts should be in the 1515 extrusion itself

Source files are available on onshape.