This one is easy.

The motion in the rear table is allowed by the slop between the clamping
sleeve and the stationary bracket. If you take this assembly off and use a
hammer to drive a small washer between the edge of the welded nut on the
sleeve and the stationary bracket the slop can be eliminated.  If the washer
is sized correctly it will bend as it is driven flush with the top of the
welded nut and will be locked in place forever.  The whole process takes about
15 minutes.

I did this about 15 years ago and it has worked great ever since.

Ed