nI recommend you idealize the leadscrew in this model to something much simpler, such as a Translation joint.nYou can have a fixed frame (bed) with a bearing block for the leadscrew and moving frame with a nut on the leadscrew. Then you just have a Joint Load of velocity to move the nut along the leadscrew.nIf you want the nut to only provide 1 DOF instead of 6 DOF to the moving frame, then you will want to put some additional links in the mechanism to free up some DOF between the nut and the moving frame so that the slide or bearings between the fixed frame and the moving frame can take some load. Or use a General Joint instead of a Translation Joint.n