I could use some suggestions from more experienced builders. I want to build a rack & screw drive portcullis.
Mount a rack type gear on the ends or behind a portcullis. A screw could travel on an axel which is not what I think we want. Now make wall slots 2 pins not 1. Mount two vertical axels with screws and if the turn one way the portcullis goes up. Turn the other way and can work as a thumb screw.
That is the theory anyway. Nothing lines up. I used 2x3 plates with vertical holes as a base plate and upper bearing for the axle, but it rubs the portcullis. The spacing between the screw and rack must be proper for correct operation yet clear the portcullis so it can travel.
A few bevel gears and a few portcullises could go up and down together if I can work out the proper parts and geometry.