This is an adaptation of iquizzle's great limit switch mount that he made (I love the captive nut design!). You can find his original here: http://www.thingiverse.com/thing:215514

In my case, I wanted to switch around the switches and place them on the moving gantry rather than on the outside. So, in this configuration, it made more sense to use his Y limit switches on my X axis. So, I've left the title as Y limit since that is what I modified, but I am in fact using them for my X axis.

I modified the hole spacing so they would mount nicely on the ends of the X axis in the space remaining when the makerslide is slid to one side (as it usually is). See pictures.

To attach the switches, since space is tight, I found that #6 5/8" screws work great (as pictured).

Sketchup and STL file are provided.