Unfortunately you are taking a very serious risk using these blades, this coming not just from me seeing home made blades but from an engineering and metallurgical standpoint
You MUST have the grain longitudinal to the blade (direction from bolt to the tip) never transverse (from cutting edge to rear edge).
If its transverse and you hit something, the object can split down the grain exactly like a splitting axe through a piece of fire wood. If its longitudinal and you hit something, the force must break across hundreds to thousands of grain boundaries. If its transverse, you just need to breach a cutting face grain boundary and it will pretty much just 'run' - just like wood with a splitter.
We all know how easy it is cut split wood standing the log on its cut end (with the grain), and how hard it is if you are trying to split it across the grain.
Due to this, angle iron has the grain transverse along its length (otherwise there is a higher risk of cracking when it is folded at the factory) hence you are taking a massive risk of blade splitting in your application, especially as there are rocks involved.
Similarly, there is a major stress raiser condition caused by the hole itself making that the failure area with the least extra force required to cause cracking.
There were victa blades recalled 25+ years ago due to transverse grain – several people were very seriously injured
| 
