Need Help Removing a Broken Bolt

[amodoko]

Ok, I have gotten a bolt stuck in an annoying place and the head of it straight ripped off in my socket wrench (I put too much torque on it). Anyways, so I got a bolt stuck without a head to it. I resorted to drilling it out completely but I have run into problems.

I heard that cobalt drill bits work best, but that titanium works too. So I bought some titanium drill bits, and I am still struggling to make any progress drilling into the broken bolt.

I need some suggestions on what to do. Will a cobalt drill bit actually work (because titanium is not even making a dent in the bolt)? Or if that isn't working, should I go straight to using a dremel to grind in new marks in the bolt to exctract it with a screwdriver or something? I don't want to buy a welder and weld on a new nut to the broken bolt, so that's out of the question.

So, if titanium drill bits won't make a dent in my bolt, does that mean cobalt won't either? Should I just dremel it out? Thanks so much, I really need some help on this one. Take care

[pushkins]

You can buy "bolt outs" you drill a small hole in the end of the bolt, tap in the bolt out and then with a crescent wrench back out the bolt. I've used these with success on snapped head bolts on race engines.
If you want to continue down the drilling out method then simply use a standard drill bit, there really is no need for titanium or anything like that, most bolts as mild steel (otherwise you wouldn't have been able to rip the head off in the first place.

[HayZee518]

what is the bolt a part of? engine head bolt, allen head bolt? is it a hardened steel bolt? drilling the bolt body and trying to use an easy out would be the first choice. an easy out can be a thing with a reverse twist. another type is a hardened steel pin with teeth that bite into the hole you previously drilled. another way is an old tool & die maker's trick and you use a prick punch and a ball peen hammer. put the punch near the thread at an angle and tap the punch with the hammer. as the bolt turns follow it with the hammer and punch around its circumference until you have enough bolt exposed you can grab it with a vise grip.

[amodoko]

I appreciate the responses so far. I have looked into a bunch of bolt removal techniques (easy outs, etc.). I don't know enough about bolts to tell you what it is. It actually had a screw type insert and the head looked like a normal bolt that I had to use a socket wrench for. It was being screwed into a hole that was filled with solder to make a new hole for another bolt.

But my main problem I guess is I don't know why I am having so much trouble making any progress drilling into the bolt. A ton of bolt removal techniques require you to drill into the bolt first, and I've spent roughly 20 minutes of drilling with titanium drill bits and only got in about 3mm, and I have about an inch to drill through.

I'm using a cordless black and decker drill (14.4 volt). I've tried using high speed drill bits and titanium drill bits. I don't know why I'm having so much trouble. I've drilled through metal once before with a crappy drill bit, and it only took me about 5 minutes to go through about a quarter inch.

But drilling through this bolt is proving to be close to impossible for me. I'm using motor oil as my lubricant. Any ideas why I can't get through this thing? I want to know if I'm doing something wrong or using the wrong tools.

[HayZee518]

then that bolt is case hardened. no amount of drilling is going to dent it. you say the hole was filled with solder and re-tapped. I almost think the threaded part is something called a heli-coil. this is a spring coil that is made of hardened steel. when you encounter a hardened bolt the last means of recovery is to use a machine called an ELOX machine. this uses a high electric current and a sacrificial electrode of copper - it actually burns the bolt out of the threaded part.

[mrcaptainbob]

Broken bolt...

I sure don't mean to be condescending, but a friend once had a terrible time drilling an 3/8" hole in the car fender one time. His neighbor came by to see what he was fussing with and noticed the drill was in reverse. A more valid point....don't use motor oil. Use either candle wax or regular cutting oil. Even Crisco works. You may have hardened the end already and maybe grinding some of it away with the Dremel will get you to fresh metal. Check for a sharp drill bit, cutting oil and you should be good to go....

[HayZee518]

while we are on the subject of drills and drilling, a slow drill is better than a fast drill depending on hole size. a 3/8 inch bolt using an easy out would need a 1/4 inch drill bit. cut at a slow speed. use kerosene for a coolant. the drill web is 60 degrees the back part of the flute right behind the cutting edge is called the rake or rake angle. higher speeds does nothing but dull bits and creates heat.

[pushkins]

Yep, the motor oil and a drill bit hot may well have helped harden the bolt. Probably didn't do the drill bit much good either.

[amodoko]

Thanks guys, I am an idiot. I am acting like a total newbie, I WAS drilling in the wrong direction (the bit was spinning in the wrong direction, for withdrawing the bit, not for drilling). I must have left it like that from when I last used it, and didn't realize it when I was drilling. So sorry for wasting everyone's time with that one, I don't know why I didn't even think about it. Thanks for everyone's help.

I do have one continuing question though. Is it possible to just screw a new bolt into a drilled hole without tapping it? Or do I need to tap it to get it in? I always thought I could just screw in a new bolt if I drilled the hole right, but I found when I tried doing that, that the bolt kept on slipping and squirming around.

[mrcaptainbob]

drilling holes

Yep, the hole needs to be 'tapped' or threaded to accept the threads of the bolt. Again, be careful what oil you use. Crisco, candle wax, kerosene, cutting oil....are the preferred lubricants. And...when threading that hole, be sure to use the correct thread count. For almost each size bolt there is a coarse thread count and a fine thread count. A coarse bolt won't fit a fine thread hole, and vice/versa.

[HayZee518]

if you know your bolt size get a corresponding tap. the threads are measured in "threads per inch" or just tpi. national coarse is a standard thread. national fine are the fine threads. per example an 8-32 screw is a number 8 screw with 32 threads per inch. a 1-8 bolt is a number 1 bolt with 8 threads per inch. common sizes are 1/4-20, 1/4-28, 3/8-16, 3/8-24, 1/2-13, 1/2-28. metrics are different. the screw size is an M with a number, like M4