The battered corner of my bench scale shows it’s been knocking around for quite a while, but the drag knife blade tip seems pretty close to the first 0.5 mm division:
The blade extends from the LM12UU holder for the MPCNC.
Scribbling the blade across a scrap of laminated yellow card stock (about 0.4 mm thick) showed it didn’t cut all the way through the bottom plastic layer, even with the spring mashed flat.
So I screwed it out to 0.7 mm:
The scale isn’t quite parallel to the blade axis and maybe it’s sticking out 0.8 mm; setting a drag knife’s blade extension obviously isn’t an exact science.
In any event, another scribble slashed all the way through the laminated deck without gashing the sacrificial cardboard atop my desk, which seems good enough.