Designed up this ruler stopper for 19.5 mm wide 0.5mm thick ruler.
i used M4 7.5 mm allan bolt. heated the bolt and press fitted to the grip part.
also made seperate one with 45 degree.
quite handy tool and fast to print.

Note: Needs a little bit brute force and grinding to slide in the ruler for the first time.

update
tolerance.

Creality

Ender 3

No

No

200

20