Hey guys. I'm back again with another stupid shop problem.
I had to tap a hole in a cylinder head for a Heli-Coil (trust me, I'd have avoided it if I could have). Naturally the helicoil tap snapped off inside the head.
I've been slowly attacking the remnant inside the hole with a variety of tools. Including a tap extractor for this tap, which just bent and failed to budge the tap in any way.
I have already tried heating the tap up and then rapidly cooling it in hopes to shatter it, as well as sharp impacts with a strong punch.
My current angle of attack involves a carbide mill/drill and a carbide material removal bur, however these seem to be taking an inordinately long time to do much of anything. Part of that is my impatience (I've been sitting on this project for a month now) but surely it shouldn't take half an hour to get a 1/16" deep divot started?
Because of the nature of the vehicle and the shape of the motor, the only even remotely appropriate tool I can bring to bear on this is a Dremel with a flex shaft.
So far I've been using plenty of oil and going slow. Are there any recommended methods to this? Would going faster harden the steel more?
If I had the resources I'd just pull the head and take it to a professional to have it EDM'd, or just buy a new head, but neither is an option.