This is one of those jobs we’d like to do if we could. It’s pretty risky.
Thankfully there are plenty of them. Bolt extractors, double nuts, stud pullers—none of that works. The power of corrosion is amazing; it’s nature’s own Loctite.
This is the third attempt, by the way. If we lose all of them, things get bad, so I’m stopping here. It won’t budge at all.
What a problem.
I’ll make a simple custom tool. The black part is hardened so the drill won’t wear it down.
I’ll screw a boss into the remaining M8, then screw a hollow M8 from the outside to center it, and drill. There’s nothing more dangerous than drilling by feel. To succeed almost every time out of a hundred attempts with minimal risk, it’s better to take the long way around than to rush.
I managed to drill almost perfectly centered. I have to drill with an angle drill in a pretty acrobatic position, so it’s extremely tiring. If the drill breaks, that’s the worst. You can’t just do this work carelessly.
In the end, I enlarged it to the pilot hole size for M8-1.25 and tried to tap it, but the threads didn’t match and collapsed, so I fixed it with a helicoil.
A stainless bolt would work too, but thinking about what happens if it breaks, steel is the way to go. The fact that it’s easy to machine is a huge advantage. And please, always apply anti-seize grease.
The tap suddenly broke while I was cleaning the threads.
I actually yelled “Argh!” But I’m not the type to force things, so I thought something was wrong. When I drilled it out, it came right out, so it turned out okay.
I found out later why it broke. There’s a handy tool on the lathe called a tapper that cuts threads in an instant. Since I use it to drill almost every threaded hole I can, it must have been under a lot of stress. Well, it’s good nothing worse happened, buddy.
The Deco-mainte is almost done, so I’ll update again later.
