There are three ways that I know of to remove backlash from a lead screw.
1. Use two nuts with an adjustable distance between them. The distance is set to provide contact on opposite flanks of the screws, thereby reducing clearance. On my G0602, this is done by a set screw which acts as a wedge between the nuts, forcing them apart. The nuts are actually a single piece slit in the middle with a small section left at the bottom. This works quite well at reducing backlash as long as any wear on the lead screw is uniform. The above video is an example of this type.
2. The second is to separate two independent nuts but place a compression spring between them. The spring tends to force the nuts apart, providing contact on opposing sides of the nut and will virtually eliminate backlash. The spring force must be greater than the the forces created by the use of the lead screw or the lead screw is used to create driving force in one direction. This mechanism adjusts to the wear on the lead screw and is useful for lead screws with uneven wear. Because it operates with zero clearance, it increases required driving force and wear on the lead screw. I use this method for my 70 y.o. Atlas/Craftsman 6 x 18 cross slide with the bias pushing the cross slide away from the spindle which works for any exterior turning. Any interior work, such as boring, the applied force must be less than the spring force.
3. The third type removes backlash by reducing radial clearance on the thread . The nut is slit axially along much of its length so the far end acts as a collet. A sleeve fits over the nut body to compress the collet on the thread, thereby removing any clearance. A spring is used to create axial movement of the sleeve. This type will be auto adjusting and provides for for some uneven wear on the lead screw while providing for equal compensation in both directions.
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