Good part, which unfortunately around wobbles on the pool ......

Good part, which unfortunately around wobbles on the pelvis. Beautiful well-varnished wood. Pleasant to sit ;-)
But on the pool finndet the part sometimes not really stop. Possible causes: 1.vllt. are the plastic rails too narrow to avoid slipping on the rim 2. The mounting screws have after mounting a very long lever so that it wobbles 3. Can it also be that the pool is too cheap and not bulky enough so that it just wobbles .........................
But otherwise very nice and processed !!!