Broken Bolt Removal
I would start with a die grinder to get a flat or slightly indented end
on the bolt. then drill with a small drill, 1/8" or less. drill all the
way through its length if possible. Increase in size until only .050 to
.075 wall remains. then use heat and an easy out. If none of this works
the next step I have done is to keep drilling larger holes until you
expose the threads of the ID piece and try tapping. This only works if
you were good at centering the drill during the first drilling, but if
you are centered it is amazing how easily the remainder of the bolt
comes out with the tap. If you ruin it at this point there is still heli
coil or insert, or weld it up and drill and retap.
Just about five minutes ago I drilled out a broken exhaust stud on my Audi
5000S, and used a #3 Easy-Out to remove the piece. I used an ordinary
steel-drilling bit (as opposed to wood and plastic) which had already seen
quite a bit of use. Took a little less than a minute to drill about 3/4
inch into the stud. I've done this before on "hardened" steel, using a
carbide tipped bit, and it went real fast.
For about $8.00-$10.00 you can get a solid carbide drill and drill the bolt and use an "easy-out" If it doesn't
work, you've only lost a few bucks. However, that's what I use to cut tool steel, Monel, Inconel, etc. I doubt that bolt is as hard as any of those. Worth a try. You can get the carbide drills at places like MSC www.mcsdirect.com J&L Industrial Supply www.jandlindustrial.com
1985 S Auto (Blauhai)
If it's a hardened bolt, about the only thing you can do is get a hole sawcutting drill bit and cut out around the bolt. Use the smallest one that will allow you to get around the bolt. You will then need to get an insert from an industrial supply house and fit the insert into the hole. The insert will have to be drilled and tapped to recieve the new bolt. This should be done before insertion. Good luck.
King o'd' Doody heads
'94 928GTS 5 Speed
I have even drilled out hardened socket head cap screws and they are like 190,000psi yield material (tough). It is a matter of enough pressure at the drill bit tip. The correct hardened tool steel or exotic or coated metal can work great. The cream of the crop is high boron tool steel. Sometimes you have to use a grinder to make a flat spot and to dimple to get the drill point to start cutting but it can almost always be done. There are always tools harder than parts. Otherwise you wouldn't be able to make the parts. To get the pressure you need to cut you need to start with very small drill sizes so that you can generate the pressure needed to start it cutting. Then work your way up in very small size increments. Patience is a major virtue when doing this. The right cutting oil helps too. I have found that if you dip your drill bits in Mobil 1 before you start and then stop periodically during the cut to dip it again that the cut goes alot easier. Mobil 1 is amazing stuff. Try it anytime you are drilling in metal.
I broke 2 water pump bolts off and broke easyouts off in both of them. Also broke a cam box bolt off in a 944 head. On all of them, I punched the center of the broken stud as best I could and then drilled them out with a Cobalt drill bit just undersize to the original bolt diameter. Was tedious but worked. Remember, the harder the metal, the slower the bit speed. Also, for another broken easyout (see a pattern?) I drilled it out with a broken bolt remover I got from Ace Hardware. The thing has a fluted/wide bit face and a screw down collar that threads over the bit. The screw down piece is slightly tapered and has wide thread pitch. I will have to go down to my garage to see the name of it. It went through the easyout like it was butter.
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