Remember Stumpy? (OK, not everyone does)
That's the old rototiller I converted to a stump grinder by swapping out the tines for an old Briggs flywheel with half a dozen carbide teeth silver soldered on the rim. The transmission was dead so it was removed and the main shaft is driven directly from the engine via a belt.
The old Stumpy:
The old Stumpy worked really well on stumps that had been allowed to decay for a while. However, I have been doing some logging to clear dying fir trees near the house and I have some sizable brand new stumps to remove. Stumpy needed to grow a pair.
The new Stumpy:
Since I built Stumpy I gained some sawmill quality carbide tooth gang saw blades. These don't resemble consumer type saw blades. They are far heavier and each carbide tooth is about 3/16" square by 1/2 to 3/4" long. As I have no saw capable of using these blades I took the poorest of the lot and Stumpy got a transplant.
As luck would have it the blade is about 1 inch larger in diameter than the old Briggs flywheel. That's perfect as the flywheel serves to prevent the blade from taking too much of a bite. The bladed is mig welded to the existing flywheel retainer.
The stumps were prepped by digging out around them and pressure washing the dirt and rocks off of them, then allowed to dry.
30 minutes later the stumps shown above are history. It cuts 10 times faster with some chips as big as your finger flying 10 feet away at times.