A friend of mine is working on a vintage road bike restoration project. He unscrewed the left locknut and cone and took away the axle of a Shimano FH-R105 rear hub, and the whole sprocket cluster and freehub mechanism fell apart, with the small bearings. I started assembling the whole freehub mechanism, but I couldn’t screw the freehub cone (which is right axle cup at the same time). I know it’s a left handed thread, tried it without the cassette and bearings. The thread is ok. But when I place the freehub cone (right axle cup), the threads won’t engage. I’m working just as described in this video https://www.youtube.com/watch?v=X9gIEG1db0s and using a similar DIY tool. However, the inner body of the freehub is somehow fixed on the hub shell.

The whole unit can be assembled without screwing the freehub cone (right axle cup), and the axle to carry the whole unit (probably the wheel has been ridden that way, beacuase the whole unit fel apart once the axle was removed) but I’m worried about the longevity of that solution, and I think It will not work properly. So what do you think, should I assemble everything to be held on the axle, or you have something other in mind?

PS I’ve posted this here, in Classic & Vintage, because I think is more appropriate than in Bicycle Mechanics.