Can you guess what this is for?
Never mind, I'll tell you.
Wood expands in hot weather and certain doors refuse to close quietly as usual. They have to be grasped by the hair, if they have hair, pulled hard and slammed hard.This doesn't always work on first attempt and so must be repeated, causing considerable ruckus on the premises. I live on the top floor of a house with three flats and do not like giving or receiving ruckus. Fortunately I have good neighbours and alleluia! quiet as well. So I can no longer sit back and wait for cold weather to restore my door's good manners.
The problem is that there is nothing to grasp. There's no handle on the inside of my front door and that's why I make so much noise when trying to close it. In hot weather.
Simple, you say, buy a handle and screw it on. Ah, yes, precisely. But I only decided an hour ago that the problem must be solved immediately and it's too hot to walk to the hardware shop which will be closed at this hour anyway. I had a cursory look through my extensive collection of bricolage materials and couldn't find a single handle. The only thing which looked remotely handle-ish was the round hole brass thingy (what are they called?) you see above. And the only thing which fitted tightly inside the thingy's hole was the handle of one of my oil painting brushes.
So, improvisation being the mother of invention, I screwed the thingy to the door at a convenient height for my hand, sawed off the thin end of the brush, pushed the fat part into the hole and presto! A graspable handle which is also, you must admit, original. And it works. I can now close the door quietly. Well, less noisily.