Ruler Marking Gauge (ruler stop block)

Refinement of @danny243 's marking gauge (himself inspired by zisoft).
A M3 heat insert is used instead of a nut.

Update 20230120:
Some minor tweaks to the tolerance settings (v11).
Tested a heat set insert with success.
I recommend to print on a smooth print bed sheet.

Update 20231126 (V2):
Added two new models for M3x20 and M3x16 thumb screws.
You'll get them at Amazon or preferably at your local hardware store.

Have a look at my other gauge: 
https://www.printables.com/model/372352-marking-gauge