Years ago a manufacturing process engineer showed me some literature from a company that made the tools it took to...you guessed it.....drill square holes.
Tony - They're called "skid shoes" and they are designed to assist the blade in "floating" on the surface so it doesn't dig in as much. They're useful in plowing snow, because the snow is usually a lot softer than the ground underneath, so the shoes keep the blade from tearing up the driveway as much. Also, sometimes they're useful for helping crown a road - you can put the shoe down level, or even a little below, the blade on the end of the blade that's toward the middle of the road, while raising it or leaving it off completely on the shoulder side. And other similar uses, of course...
I made mine like the ones in DFBs picture. I used skid plate for a trailer jack. Welded pipe to my blade, and pined the shoe to a smaller pipe. It work on my gravel drive.
I noticed that blacktop was mentioned a couple of times. Is it a good idea to use these when plowing blacktop to protect it or is it better to just swing the blade around backwards? Thanks.