I find that most toilet seats loosen where they bolt to the toilet, especially if the bolts are nylon instead of brass. That’s because you can make the nylon nuts only so tight without stripping them, and they loosen with use in no time. My solution to this problem is a pair of lock washers made from an old inner tube. Like fender washers, my lock washers are big: 1-1/8 in. dia. with a 5/16-in. hole.
I put one of these washers under each toilet-seat nut and hand-tighten. I haven’t had to adjust them since.
Joseph Kaye, Phenix, VA
Edited and Illustrated by Charles Miller
From Fine Homebuilding #152