Used Mill X axis won't move manually

[redneck engineer]

Hey all, I'm new to machining so please forgive my lack of knowledge of the appropriate parts. I recently bought a used Vernier universal mill. The x axis won't move with the manual handwheel. When spinning the handwheel the shaft connected to the handwheel that spans the table length spins but it doesn't turn the screw that runs alongside it. Power feed works as it should. I cannot see how the handwheel shaft connects to the screw from either end so I suppose i will have to remove the table. I suspect theres a keyway or gear thats come off. thanks for your help.