Broken Bolt...How to remove?
Thread Starter
Instructor
Joined: Sep 2007
Posts: 175
Likes: 1
From: Fort Worth Texas
Broken Bolt...How to remove?
Ok, I was putting an engine block on my stand and one of the bolts snapped off while I was tightening it. It was weird, because It wasnt tightened all the way and the rest of them were. The bolts were supposed to be Grade 8....What now? Thanks, Zak.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
If it broke because you crossthreaded it, you have problems. If it simply broke (and I have never, ever seen a grade 8 simply snap),
drill the center out of it and twist it out with an easy out.
If it is cross threaded. Take it to the machine shop. They will drill it out carefully, and install a heli-coil thread insert to restore the threads.
drill the center out of it and twist it out with an easy out.
If it is cross threaded. Take it to the machine shop. They will drill it out carefully, and install a heli-coil thread insert to restore the threads.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
I agree with the Batmobile as I have never experienced a grade 8 breaking during the insertion process. Did you attempt to put a metric thread in an English tapped hole or vice versa?
Melting Slicks
Joined: Jul 2003
Posts: 2,384
Likes: 124
From: Reno/Sparks Nevada
This is an interesting subject. A few things come to mind with my experience with broken bolts.
Was the bolt hard to start and did it continue to be hard to turn til it broke? If so, then it could be crossthreaded or the wrong thread was used which in either case no easy out is going to remove. It will have to be drilled out.
Was the bolt easy to start and did it continue to be easy to turn until it stopped and then broke. If so, then it is usually due to the bolt bottoming out or too much torque was exterted. This type of break my allow the use of an easy out of some type because once the bolt broke then the pressure on the threads was released allowing the broken piece to be removed by drilling and using an easy out or a left handed bit. If it was a grade 8 then you'll need a harder drill bit. This situation also lends itself to simply using a pick and backing out the screw tediously until you can get a grip on it. Highly unlikely to do but I've been able to do it on occasion (exhaust manifold bolts).
Depending on the type of fastener, the force needed to start it in the hole, the force to turn it until it broke and the torque exerted before the bolt broke will determine what the next course of action will be.
Art
Was the bolt hard to start and did it continue to be hard to turn til it broke? If so, then it could be crossthreaded or the wrong thread was used which in either case no easy out is going to remove. It will have to be drilled out.
Was the bolt easy to start and did it continue to be easy to turn until it stopped and then broke. If so, then it is usually due to the bolt bottoming out or too much torque was exterted. This type of break my allow the use of an easy out of some type because once the bolt broke then the pressure on the threads was released allowing the broken piece to be removed by drilling and using an easy out or a left handed bit. If it was a grade 8 then you'll need a harder drill bit. This situation also lends itself to simply using a pick and backing out the screw tediously until you can get a grip on it. Highly unlikely to do but I've been able to do it on occasion (exhaust manifold bolts).
Depending on the type of fastener, the force needed to start it in the hole, the force to turn it until it broke and the torque exerted before the bolt broke will determine what the next course of action will be.
Art
Last edited by MrRenoman; Jan 1, 2008 at 02:56 PM.
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Safety Car
Joined: Apr 2004
Posts: 4,532
Likes: 7
From: Lahaina Hi
I broke a grade 8 on a splade main cap.The machine shop did not drill the threads all the way down and when removing it the end of the bolt snapped.Use the reverse drill bit you can get for drill presses and use the smallest bit to start with that you can.
Racer
Joined: Oct 2007
Posts: 250
Likes: 1
Hello,
There isn't anything EASY about an easy-out! If there is any part of the bolt hanging-out, weld a nut on to it and use tools to remove it.
If it is cross-threaded, drill it out and install a heli-coil. If you are not equipped to do this, get a shop to do this. By the way, NO Shop is going to garuntee this work. They are trying to patch your 'screw-up'.
Take Care and Be Safe, -John
There isn't anything EASY about an easy-out! If there is any part of the bolt hanging-out, weld a nut on to it and use tools to remove it.
If it is cross-threaded, drill it out and install a heli-coil. If you are not equipped to do this, get a shop to do this. By the way, NO Shop is going to garuntee this work. They are trying to patch your 'screw-up'.
Take Care and Be Safe, -John
Burning Brakes
Joined: Jun 2005
Posts: 1,191
Likes: 15
From: Wallingford Vermont
Here's the latest style extractor http://www.brandsplace.com/0384-ald3017p.html
There's also a special welding rod/sytem Cronaton 333 that adheres to the bolt but not to the cast block. http://webapp1.cronatronwelding.com/...temNum=CW03030
Good luck
There's also a special welding rod/sytem Cronaton 333 that adheres to the bolt but not to the cast block. http://webapp1.cronatronwelding.com/...temNum=CW03030
Good luck
Pro
Joined: Sep 2006
Posts: 702
Likes: 2
From: Conyers Ga
Here's the latest style extractor http://www.brandsplace.com/0384-ald3017p.html
I've used this type at work with great success.........
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
Also you may consider filing two flat spots opposite each other and using an open end wrench to get it out. (assuming of course that there's enough of it sticking out to do so.)
