#1 to try: Keep knocking on it with that punch and maybe it'll break up into pieces and come out that way. I recently had to resort to that method, it chews up the punch but otherwise works fine.

#2 Heat it with a torch until it is cherry red, then let it cool slow. That will soften it up some. now you might try drilling it out.

Just some FYI that I have found out in my own experience: If you are trying to use an easy out on a bolt whose head twisted off during removal, forget the easy out. Your chances are near nil. your best bet is to get a real, REAL good center punch on it, then start drilling it out starting with probably a 1/8" drill, and stepping up by 1/16" increments until you reach the correct drill size for tapping the fastener. Then run a tap down in to pull the last of the bolt out.

However, if the bolt head twisted off during installation ( over torquing ) then you have an excellent canidate for an easy out. If however, the bolt was cross threaded, and the head twisted off before it was fully seated, drill it.

If you dont' see the difference: When the head twists off from over torquing, the threads are allowed to relax. Often you can just use a punch to kind of spin it out, don't even need to drill for an easy out. OR.. get a set of left-handed drill bits to drill for the easy out. Usually you will end up spinning it out with just the drill bit.

If the bolt is rusted in, else cross-threaded, then the threads are bound up and you will have to put more torque than the bolt itself was able to tolerate for removal. Likely the easy out will snap just as quick as did the bolt.

Since I am passing on about a decade of easy-out knowledge here, I'll plow on: There are several types of easy outs available. The left handed screw type works well on bolts, but not advisable for broken pipe nipples. For pipe nipples, you are better off with a tapered square type. The difference being, as you torque down on the screw type easy out, it is boring deeper into the material, and creating additional pressure on the threads, thus actually working against itself. Along with that theory: When removing broken out pipe nipples, don't try to get it all at once. Tap the ( square ) easy out in, and turn it with a wrench till it breaks free from the nipple. Repeat this several times. About the time you get tired of messing with it, and decide to set the easy out real hard, the threads will have loosened up enough to get the piece out. It REALLY does work better that way, compared to just slamming the easy out down in, and trying to get it 'all at once'.

My greatest difficutly in removing bolts has been exhaust manifolds. One good tip is to really SMACK the head of the bolt with a 32 oz hammer before you put the wrench to it. This tends to shock the threads and helps to break up the rust.

If it is a stud, you might like to put some good heat to it ( never heat it past a dull cherry red ) and some light oil. The heat will pull the oil into the threads. Penetrating oil is almost useless on fasteners which have only the head showing. Until you shear the head off, and pull the manifold off, leaving the broken bolt protruding from the head. Then you can get the oil to the threads using the heat. When you are really lucky you can grab it with a pair of vise grips after applying the heat & oil and get it out easy. If it looks like no amount of oil and channel locks will remove the protruding bastard, cut it off flat to the head, center punch, and start drilling.

Now, it is quite a feat of ability to actually get the hole drilling on center. usually you will be a little bit lopsided and therefore you can't drill to the full tap size. If you did, you would end up with a lopsided hole. In this case, you step up by 1/64" until you have reached threads on one side. Then use a punch on the 'meat side' of the remaining fastener in the hole, and punch it into the hole. Reach in with needle nose and pull out the remains. If you can get at least the top quarter inch of the hole clean, then you can run in a taper tap and try to chew up the rest.

I guess one last nugget and i'll be through: for removing rusted - in plugs: Get the braizing tip on the torch, and reach in the hole and HEAT that little bastard. Then, splash it with some cold water, and put your hex wrench on it and spin it out. If it don't come, then repeat. The heat/cold will shock it loose every time.

Now, obviously I have written this to benifit those of us without extensive machine shops. Otherwise I would simply have said to pull the head, chuck it up in the drill press, and put in the carbide bits, achieve a perfect center and drill the bastard.