Say goodbye to the unsightly ends of your Y-axis MGN12 linear rails with these delightful bumpstop endcaps, replete with tiny ZeroG logo.
These also serve a functional purposes of making sure your linear rail carriages cannot de-rail, avoiding a messy train crash.
The 'stopper' is held in place with an M3x10mm bolt and t-nut. (If you do not have any M3 t-nuts handy, there are many printable options on Thingiverse that will convert an M3 hex nut into a t-nut.)
The 'cover' then slides over the 'stopper', hiding the bolt and completing the arrangement.
The 'cover' has a 1mm overhang onto the rail, given a lot of Chinese linear rails do not have nice straight ends, so you will lose 1mm of travel at each end you use the bumpstop caps.
Be mindful that these use up space between the front of the rail and the front belt tension towers; nonetheless, they should work in all but the most extreme cases of long(er) rails almost butting up against the towers.
The 'covers' can be printed (oriented as they are used) without supports assuming your printer can manage short bridges. Some minimal cleanup of the underside might be required.
I do not recommend printing the 'stoppers' in ABS, oriented as they are used, unless you have a perfect printing environment as the parts are tiny and the overhangs in the first few layers are steep.
It is best to print the 'stoppers' on their side as the overhangs for the M3 bolt recess are much more manageable; the STL is oriented for printing like this.
Alternatively, you can print the 'stoppers' upside-down and live with a little bit of clean up (or, if you must, cheat and use supports when printing upside-down).
Given their tiny size, consider printing several at once to aid layer cooling.
Your mileage may vary with other, easier to print filaments.
