I'm replace the control arm and in getting the old one out we had to cut the front bolt and now part of the tip is stuck in the threads (still in the collar). I bought a cobalt drill bit (suggested for drill through hardened steel) but it won't drill through. Help?!?!?!?

 

If you are replacing the c arm , why not just cut up with a torch or an angle grinder.
You can cut the rear part to alow it swing up and down so you can cut it close to front arm bushing.
That bolt is frozen to the sleeve that is inside the bushing and can be a bugger to get out without cutting.
You should also put the rear bolt back ,because to holds the k frame to the body , while you deal with the front bolt.
good luck.

 

well no you see. We already did cut the bolt, the c arm is not on the car anymore. The problem is that part of the bolt that was cut is still in the receiving end so we can't put the new c arm on until we get that cut bolt out. And as I said we tried using a drill bit and easy out but there NOTHING that will drill into this thing, I went to ace and got the BEST drill bit (that they claim will go through just about anything and everything, cobalt) and that didn't even do it. But what we might do is just cut he bottom out of the receiving end and try and get it from that side. I just want to cut anything that I don't need to.

 

You could try some oxy\acetylene heat and a suitable sized drift\punch?