Tools for removing / extracting left hand (reverse) threaded bolts

I was wondering if anyone had any suggestions / preferred extractors for removing a broken left hand (reverse) threaded bolt beyond the use of penetrating solvent and a straight flute extractor.

I had a coworker a while back borrow one of my drills, then proceeded to chuck up a 1-1/2" ship auger bit, got it stuck and snapped the chuck retention bolt when trying to reverse the bit out.

I am trying to figure out whether I want to just buy a new drive spindle or if it is possible to remove the bolt. The bolt in question is a 1" 1/4 20 hardened steel bolt.

When it initially got broken, it was still under warranty, however, the repair shop's only solution was to cover the threaded between the chuck and spindle with loctite, which would prevent me from being able to ever disassemble the drill.

I haven't tried working on it as of yet, but just wanted to get peoples thoughts on ways of removing it. My thought right now is to remove the spindle, chuck it up in my drill press and drill out the bolt, slightly pound in a straight flute extractor and hope that it breaks loose. If not, I am just going to end up ordering a new spindle.

Got to love coworkers sometimes.

bill the repair shop.../ or coworker

use a normal RH drill bit. drill it out to a tapped hole size for whatever size bolt is 50% the size of the broken bolt. ie. 1" bolt, use a 1/2 bolt and drill it out for the tapped size.

then use a grade 8 bolt or stronger and just drive it in normally . RH thread bolt will turn a LH out. should work just fine in theory, just like a screw extractor, except buying a lh extractor would be expensive. and no one has high grade lh bolts laying around to extra rh broken bolts

as for hardened bolts like that. you may have to put a torch on it to get the bolt red hot before drilling. drill it while its red hot and after it cools rapidly it will leave plenty of room for shrink to loosen the threads up and make it easy to extract.

Thanks for the advice. I was able to remove a Left-Handed chuck screw in my drill where the head had broken off and the remaining screw was deeply recessed. It took awhile several different sized bits. Considered the advice to "heat" the screw since I knew it had loctite on it. Instead of a blowtorch, I used a duller bit and drilled until it was smoking hot, the heat softened the loctite and the LH screw simply spun right out.