Placing brakes on walls, pointing downwards

[Tehanu]

I can't seem to manage it, and no one seems to have had the same problem, going by what I can find. I'm a dumbdumb, so can someone explain what I'm doing wrong? I just want to halt the mill whenever I'm not specifically grinding something.

[TristamIzumi]

Some mechanical blocks, like the transmission+clutch and the brake need to be placed along a horizontal axle, at least that's what I experienced when I tried placing a transmission+clutch vertically.