The big trees of KnuGi (neglected) are particularly hard so it is difficult to split wood with an ax.
I had to break it up with a chain saw and it was not broken by a woodwood splitting machine (7 tons).
So I cut the groove about 5 cm with a chain saw, and when I used wedge, I made it quickly. I used two hooks, I could hit with a big hammer, my head was not broken and it was moderately soft so I did not fly fragments and I sharpened the tip a little with a grinder. It was better than price.
I used it when I knocked down a 60 cm diameter cypress. This cypress has been cut off in the past for more than 8 m and has already withered. However, we predicted a considerable weight for the big trees, decided to pinch the chain saw with a wedge and to define the direction to be knocked down. It was my first use, but as a result of driving carefully according to the tension of the rope, I was able to beat almost in the target direction. The wedge shape was also good so it was easy to handle. I repeatedly browsed posted videos before construction and studied.