The drill drills, but is suitable for sand or clean soil without stones and roots. The problem is in the tip of the drill, it accounts for the main breakdown force, but it does not at all. When drilling, it is required to exert a force on the drill from above, and so, if the spear rests against the slightest obstacle, you will not drill anything. I drilled 15 centimeters and rested against the root, and on my second attempt I rested my point on a stone.
Of course, you can try to hammer a drill with a sledgehammer, but this is not serious. Well, or you need to pull out a drill and break barriers with a crowbar.
The disk, by the way, bends easily.
At the end, you also need to weld some kind of mini-drill, which will pull the main knife down and break through obstacles. I thought of adding a piece from a hand-held old drill to a tree at the end, but I could not find where it disappeared.