leadscrew nut re taper attachment

[f350ca]

Peter
I think I may have figured out the mechanism. Lots of moving an pivoting parts.
Here's a really rough sketch of what I think is going on.



The trick is the screw for the cross slide isn't fixed to the carriage but the taper attachment and a sliding spline is used from the handle to the screw.
The base for the taper attachment is fixed to the carriage. The taper attachment when fixed to the bed then slides in that dovetail. The taper is set above that. A block slides in the taper attachment the screw is threaded through it. Turning the screw (though the spline) moves the cross slide on the carriage, or the block sliding in the taper moves the cross slide when the carriage moves down the bed.

When the taper slide is disconnected from the bed everything moves together and only the thread moves the cross slide.

Hope this makes some scene, not sure it does to me.