In a large bulk purchase we acquired a bunch of O27 switches with the steel boxes on one side.
If you own some you probably have run into the same situation that we have that they are very difficult to service due to the rivets on the bottom side. On some of the switches I noticed a very small hole in the side of the switch. It looked rather strange, but that particular switch had a very sluggish action. For experimentation i gave it a squirt of motor oil, and wallah! the switch worked excellent. We now are drilling holes in all the switches we have that did not come that way from the factory. By the way, anyone know of a supply of those bend around red and green plastic pieces for those with top lights?