Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4702242.
i made this gage to make it easy to set the focusing the laser of the neje master to 30watt laser that i have.
it is in mm. in 1 mm increments. with numbers in 5 mm increments.
its neat cuz once the laser module is loose and set the red plastic bottom of the module at the top (40mm) of the gage and pull the gage out the module falls down the next steps following the gage. allowing you to view at the same time the laser dot. easy to compare right away the different focus diameters to pick the best exact one. its almost automatic. and its super fast to set the focus. you dont have to set it each step as you would with the ortur where you have to turn the focus lens each time.
you import the dxf into your laser software. or you can print it out once you extrude it for your 3d printer if you like.
it might be useful for other laser cutters/engravers.