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Removing broken bolts

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I

ichthos

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Hello,
After all the information on bolt grades, I realize one thing I have been guilty of is not replacing bolts that have been previously torqued. This may explain why I have broken bolts when torquing to specs. Most of the bolts I have broken have been ones that are rusted and have been in the car a long time. In any case, is there anyone that can give me good instructions on how to remove broken bolts? I have tried a number of times with little success. I recently broke off a bolt in a flywheel. I was able to finally get the bolt out, but I messed up the threads. I have taken pieces with broken bolts to a machine shop and they never seem to have any problems with removing bolts - this tends to be expensive, however. Besides, I would like to learn how to do it myself. The more detail, the better.
Thanks, Kevin
 
Any time I break a bolt I usually drill a hole into the bolt, spray the heck out of it with penatrating oil ( WD40 or somthing simalar) and use an easyout. It takes a little time but thats the only way I know. You can get a nice set of easyouts at Sears for a reasonable price. Good luck
 
My favorite trick is to get a left-handed drill that is about 3/4 of the size of the bolt diameter. Make a good center punch mark, be sure the drill is in reverse, and commence drilling. Often, the broken bolt will spin out after a bit of drilling. A bit of penetrating oil ahead of time is always a good idea.
I've broken several EZee-Outs....once they break in a bolt, things can get pretty difficult.
 
Are left handed drills common? Are they distinguished as left handed in the store? That sure would make more sense to be dilling in the direction you want the bolt or screw to go. I have heard about using heat, but many times that is not an option. I am leary about using and easy out - I have managed to break these off a couple of times after following the directions to the letter.
Kevin
Thanks, Kevin
 
Kevin- The left handed drill bit is a handy trick. If you plan on owning one of these babies you need to know all the tricks to get broken and stuck hardware off.
don
 
Hello Kevin,

no, left handed drills are rare, but for the purpose above it may be worth grinding a standard drill the opposite way, i.e against the helix. It will not clear the swarf very well so may take a few goes.
What ever method you use, try and take time to drill the broken bolt\stud centrally (not so easy if the component is still on the vehicle) but if the broken piece will not come out then it can be drilled right up to the core diameter and re-tapped. (Having a set of taps and dies of the common threads is worth the expense if you do a lot of car work)
(Not really an option if you have broken an easy out in there though :-( )

Alec
 
Alec, left hand drills are readily available over here, at any of our tool supply houses. They are generally about twice the cost of a right hand drill.
For instance, I'm looking at a 1/4" RH, at $2.00, and the same in a LH at $4.25.
I would think that an Industrial tool factor on your side of the pond would carry them as well.
Jeff
 
LH drill bits are available online over here in sets from Northern Tool.

I don't wish to sound too negative but I never use EasyOuts. My reason/logic is as follows. What you're dealing with is a bolt... a bolt that used to have a head. You had to apply so much torque to it that you sheared the head off. To use an EasyOut you drill out the core of the seized and broken bolt... then insert a smaller diameter hard but brittle thing to remove what couldn't be removed before. If you break an EasyOut in a bolt, you'll be paying the machine shop to EDM the broken bit out.

I do what Nial does except I drill out the center of the bolt with a regular RH drill bit first, removing about 1/2 of the diameter of the bolt before switching to LH bits. When I don't have access to the LH bits I drill progressively larger holes down the center of the broken bolt until I start to see the roots of the threads and then I pick the remainder out. Slow but effective.
 
I've done easy outs (and broken them off), center drilling and as noted here, reverse drilling. I've lately been using the big hammer/little stick method. A big 1/2 reversible electric drill with a relatively small but good quality bit. Much less time involved!
 
Thanks for all the information. I'm glad I'm not the only one that has problems with the easy-outs. I always get nervous using them becasue I know once I break it off, the job is pretty much history. The local machine shop won't even look at it if you break off an easy out. I know that drilling the hole out directly in the center is important in using some of the other methods. Normally when the bolt breaks off, however, there is a hight point where it is twisted off in the center. Are there any tricks to drilling the hole directly in the center? I can usually get close.
Thanks, Kevin
 
There are a couple of things you can do to center the drilling better IF you have a couple of extra tools. If you have a Dremel or die grinder you can remove the high spot from the broken stud so you have less chance of the bit walking off center. Sometimes the mating part can be left in place and used as a drill guide. This often means starting with a way-too-big drill bit just to get a center point started. If that's too risky for you, you can make or buy a transfer punch. These are punches with straight sides (ODs) to fit the ID of the hole in the mating part. They assure your center mark is on center.
 
Rigid makes an excellent, though expensive, set of easy outs. They include collars that you position to help with centering while drilling.
There are many different types of easy outs. Spiral fluted, straight fluted and standard straight are three of the most popular. The first two are tapered, so as you drive them into position, the tapers are wedged into the fastener to provide for bite.. The standard straight is not tapered, but has ridges running the length of the tool.
Some people don't like the fluted variety because they feel the taper drives the sides of the fastener tighter into the hole. The straight type does not do this, as the ridges cut into the fastener to provide grip. Hole size is very important with this type. This type seems to be favored by many of my customers.
The heat from drilling often helps free the broken fastener.
Easy outs, as anyone who has ever used them can attest to, are not the perfect tool. But time and patience are best when using them.
 
I only scanned the previous posts, but I sense they covered this topic well. My Grandad's formula for broken bolts was "patience, perseverence and sweet oil" I'm not sure what the sweet oil was but may have been reference to Marvel Mystery Oil which has a sicky sweet smell to me. I think he inadvertantly left out "prayer" as a critical first step as sometimes, though rarely, these things can be miracuosly easy. My own experience is that "Liquid Wrench" is demonstrably better than other penetrating oils I've tried and drilling a hole completley through the stud is best, as it sometimes seems to relieve the pressure on the bolt so it will back out easily.
 
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