I need ideas for how to get this stripped lock nut off. It's an engine mount bolt on a dirt bike. The bolt head is hex-shaped (no issues on that side). The lock nut just spins. I've tried using vise grips to "pull" the lock nut in hopes of the lock nut "biting" on a good thread. No luck. I'm out of ideas besides cutting the bolt which is in a hard-to-reach area.
Old flat blade screwdriver, (grind thinner) same wedge shape, to force between nut and frame/bracket. With a closed end wrench, unscrew it while you put pressure with the old screwdriver- the goal is to bite into decent enough threw to start unthreading. Or a small chisel may work. You're just trying to move the nut out enough to bite into hopefully good enough threads to unscrew. All I got. Good luck.
Thanks. I'll try that before going with @damiankelly 's near-nuclear suggestion. One of those suggestions should work. Thanks.
Looks tough to get to but I usually reach for the dremel or die cutoff tool with a small cutoff wheel and zip it off. The dremel will reach into tighter spaces but you have to keep tight control of it so you don't nick something you don't intend. Sometimes just getting a groove started is all that's need then the chisel to finish things off.
Take the bolt head that you CAN get to on the outside. Cut a cross in it with a die grinder. Take a chisel and bust off all corners so it is flat. Take a punch/hammer and ram through the rest of the bolt. Replace with new
Not the fastest way but the safest, just drill out the center and go bigger until you reach the threads on the nut. Chisel and a hammer seems like a good idea, but I think its kinda risky with aluminum behind it that can possibly crack and open another can of worms.