Head Broke Off Bolt...Please Help!!

[Scotty370]

Chilly- My only thought are A) I've never tryed to 'plunge' arc a weld, through a nut, and into a hole, and don't feel I be willing to try. and, B) I think that the broken drill bit is the most problematic part of this attempted fix! Once the drill piece is out, drilling can resume, thread-picking can happen, and worst case, oversize drill it, tap it, and insert a Heli-Coil. But the broken drill is the killer! ~S

PS Interesting idea Dave!

 

[Prodirt6000]

Yes the drill bit is the major problem here. If I knew of the best way to get that bit out of there, I could go on with my usual way of getting these bolts out. Just that bit is killing me.

And dave, will that still work even though the bolt is upside down?

 

[CurlyDave]

The wax trick will work with the bolt upside down. Capillary action "pulls" the molten wax into small cracks, and it will travel up the threads of the bolt.

If you only need to get the drill bit out, get a grade 8 bolt of the same size as the drill bit. A long one, only threaded on the end, you want the head and a smooth round shaft.

Now, using a dremel tool, cut the long bolt to the shortest practical length and cut two "nubs" on it that will engage the flutes of the drill bit. This will be a time-consuming pain in the rear, but you may be able to push these nubs into the flutes on the drill and back it out.

Start by cutting a slot, sort of like a screwdriver slot, in the shank of the bolt, and have a drill bit of the right size next to you so you can shape the nubs properly, lube it all up, heat it a little and give it a try. This won't screw anything up any further, and all it will really cost is a lot of your time.

 

[Egon]

This may sound weird but can you use a hole saw to remove the mess and then retapp the new hole ???

 

[dex3361]

What size is the bolt? I didn't see it mentioned.

 

[Egon]

Randall:

I have a bolt probably around 3/8 inch I think that the head broke off of it in the casting.

 

[Kernopelli]

Turn your welder up some more and bury the rod in to the stud through the nut. I use 7018 rod. 3/32 would be a good size. I think 6011 is too brittle and 6013 not strong enough. The weld will not stick to the cast very well so don't let that scare you. Let it cool till the weld chills but don't let it cool off to the touch.

Did the original bolt break off or twist off while being removed. If you twisted it off you may not get it out. Can the casting be removed and taken to a machine shop?

Dan

I have a good friend that is not only the best machinist and welder I've ever known but one of the most particular guys on the planet....."do it right or don't do it at all" would be a good summation of his work ethic and how he approaches everything in life. He swears by this method of removing broken bolts in blind holes. Instead of 7018 rods, he uses stainless rods though. We talked about this just recently and he said he has used this method tens of times and never had it fail. He says the stainless rod will penetrate the nut and bolt but not the cast iron or steel it is threaded into. If I didn't know the man so well I may doubt this line of thought but he went as far as bringing me some stainless rods for this very purpose, in case I needed them in the future. I will see him tonight and ask him for further information about this technique and post tomorrow morning what he says.

 

[dex3361]

Randall:

As usual I miss the important stuff. Thanks.

 

[BXpanded]

Do I understand the bolt went in from the bottom so you are working overhead?

Also, did the bolt break in use or did it break as you were tightening or loosening it?

That info might all be here but I don't have time to read the whole thread right now.

 

[mostly_gas]

I have had luck with using a center drill to drill out drill bit if I can't easily EDM it out.

 

[dodge man]

The helicoil is the best idea, it comes with a drill bit will put new, original sized threads back in place. Save the drill bit that comes with the helicoil kit and use other drill bits to get the broken drill bit. It will be a ***** to drill out the broken bit, but if you use some high quality drill bits and enough of them you will get it.

 

[KennyV]

When all else fails an Electro Arc Metal Disintegrator will work.
YouTube - Electro Arc Metal Disintegrator
Some machine shops have portable units that can be taken to the field.

Also very user friendly... if you can get to it, QuikCenter Broken Bolt Remover
YouTube - QuikCenter Broken Bolt Remover

 

[Egon]

Put a milling bit on a good drill and with patience a new hole will appear.

 

[Prodirt6000]

Hey guys thanks for all the great replies and ideas,

I did get out the old bolt today. I ended up using a small punch and punched the broken drill bit up over the bolt into the empty part of the hole. (I say up over the bolt because it was upside down). Apparently there wasnt much that broke off the bit I guess. Then I drilled the hole a bit bigger. Next I tryed heating up the casting with the torch and using the easy out to back it out. Had no luck...Didnt want to break another EZ out in there so I stopped. I sprayed the heck out of it with PB Blaster (we got cans and cans of it on the farm...works amazingly!) up into the hole and all around it by the threads. I did this a few times through out the day. Finally I put the torch to it again and used the EZ out with a Cresent wrench on the end of it. The screw finally gave and boy, it turned out hard! Even with all that leverage from the wrench. Yup so thats my story.

Thanks again guys!

 

[Scotty370]

That's Great!! I hate that 'moment-of-truth' period, when torquing an E-Z out! You know the one: Bolts going to move, or tool's gonna 'snap'!

 

[Egon]

Good show. Perseverance with tradition methods just may be the ticket!

 

[boxygen]

Congratulations, this is the type of project that can take years off your life sometimes! I've had good luck with PB blaster in the past. I had a brake rotor rusted to the hub of my truck. Sledge with 3'handle and full swings wouldnt remove it. Pipe on the end of a chisel driven into the vents of the rotor had no luck. I showered it with Blaster and the next morning it literally fell off the hub with a light tap of the hammer. It made me a believer!

 

[NH-Rob]

a farm mechanic once told me that if he drilled the bolt and then migged a nut to it filling in the drilled out portion and the nut with weld it would be much stronger and usually come out. Me i hate to drill so i just weld the nut to the bolt but if it was truely that stuborn i might try it.
Rob