ArlyA, I have a good set of cobalt bits that should be able to do it as long as I don't overheat the bit.
Ford850, I used Loctite red after the first one came off. No luck there.
Drill through grade 5 bolt's is a pain. Yes doable, but tough. Drilling little holes through Grade 8??? Does not sound like a fun job.
MechanicalGuy, all replacement blade bolts sold that I have found are forged grade 8. I assume the engineers who designed these bolts know what they are doing.
MechanicalGuy, all replacement blade bolts sold that I have found are forged grade 8. I assume the engineers who designed these bolts know what they are doing.
How can the bolt be turning? The OP posted a link at the top of the thread to the bolt he uses, which has a key to keep it from turning. He also said there was a notch in the hole to fit that key. So if the bolt can't turn, and the blade swings free on the bolt, what makes the nut back off? It can't be the movement of the blade because the bolt can't turn in the hole.
The OP said in post #5 that the notch that holds the bolt is in the plate that's welded on stump jumper. So the blade swings on the bolt, which is fixed to its attachment point on the stump jumper. That's the way my Bush Hog rotary cutter worked too.
So the bolt is supposed to be fixed, and the nut is against another fixed plate. So neither should turn. But it seems the nut does. How?