Why is dental work of the horse called "floating the teeth?"?

what is the origin of this term?

Why is dental work of the horse called "floating the teeth?"?
The tool used is a float. It is a rasp about the size of a pack of gum attached by pivot to a long handle so that the rasps "floats" over the surfaces for a better job of smotting the sharp surfaces. The phrase developed from this. It's verbal shorthand and easier to say "Float the teeth" than "Use the floating rasp to file the teeth".
Reply:To float a horse's teeth certainly sounds funny, too. Floating means to smooth or contour your horse's teeth with a file (called a "float"). Unlike your own teeth, your horse's teeth keep growing. At times, your horse's teeth may develop sharp edges, making it difficult for her to chew food, hold a bit, or simply have pain and discomfort inside her mouth.
Reply:i have no clue but "floating" is when they file down i horses teeth