How to correct the accuracy of the linear guide
 
  It's hard to completely rework the guide rails. But if you just want to make it more accurate than it is now, there is still a way to do it.
  If the two linear guides are used in pairs, first loosen the two sliders on one of the guide rails and the assembly screws of the workbench. Push the slider from the outer side of the guide rail by hand while locking the push slider. The upper screw. The other slider is still working. Then the other side rail is preloaded. The method is the same as above, but two people are required to operate. You push the slider here and push the table on the other side. , with you to push.
 
This method uses the combined orientation of the four sliders to eliminate the gap. After the operation is completed, you need to try the smoothness of the workbench. The next method is more professional, that is, to change the steel ball inside the slider. The rod will be relatively simple. As far as the screw is a double nut, it is very good. Only need to thicken the pre-pressure washer. Loosen and remove the positioning button on the double nut. Take out the preload Washer (two and a half circles), the simple way is to attach the paper on the top and then plug it back. You can choose the thickness of the paper according to the tightness of the screw. If it is a single screw, it is more troublesome. The solution is to add preload.