If you see it done you would think that is real easy. It is. The whole thing is alignment. If you drill a straight hole and don't move anything but the drill bit and tap the hole using the same setup the thread in the hole has to be straight. In order to do that, the tap has to be lined up like the drill bit was. A taper will find center. The spring loaded taper keeps the tap lined up in the same plane as the drill bit was. You end up with a screw that will go in straight. If you can maintain alignment, all the holes can be drilled first and then tapped. You are better off doing them one at a time. It will take longer but less chance of screwing up. The tapered pin stays in the chuck putting a load on the tap so it threads the hole straight. As the tap threads, the spring extends and keeps pressure and alignment on the tap.  One end of the spring pin is in the drill press chuck. The point end of the spring pin is centered in the small hole on the top of the tap wrench. I did not mention, the spring is not exposed, it is a internal part of the tool. I just used this rig today to tap some holes in a new fixture I am making. More on that later. I also used Flat head screws on my forms. The taper on the screw heads will align themselves. The screws are starnderd flathead socket screws purchaced from tool supply houses. They can be found in some larger hardware stores. I used 5/16-24 thread. This makes for finer adjustment. Another thing is there are no screws sticking out on one side to get your knuckles. I did use starnderd socket screws for the Push screws. Flat head screws are not the best for the "push" screws.