Broken bolt help for all, How to remove stuck threads Options

[Brodie]

First post for me on 914World.com. What a great forum it has helped me greatly on my research.

There is one thing that I have noticed as I have searched through these forums, and that is everybody struggles with stuck bolts or broken bolts. I see it everyday at my work. My family owns a machine shop, and we do a lot of repair work. We see all sorts of broken bolts, stuck parts, etc. Let's use this thread to help those guys out with all sorts of scenarios.

First tools of the trade, and I am sure that I'm going to miss a few.

1. Wrenches, vise grips, screwdrivers. (any bolt or screw removal tool)
2. Hammers (steel, rubber mallets)
3. Brass drift (chunck of brass)
4. Penetrating oil (Everybody has their favorite mine is chesterton spraysolvo)
5. Torch
6. Welder
7. Quenching bucket
8. Punches
9. drill bits
10. Old taps and nut chasers.

Notice that I did not include easy outs as a tool. I think easy outs are the worst tools to use. Here's why...... They rarely work on a truly stuck fastener. Most of the time they break off when you are trying to remove it. Now you have a hardened steel piece in the middle of your fastener. Drilling is no longer an option.

Let's talk penetrating oil. Some people think that all you have to do is spray penetrating oil on your bolt and it will magically remove the screw. I believe that penetrating oil is only semi effective. Let's say you have a 1" long bolt stuck in a housing. The bolt is rusted in really good. You soak it for a week with penetrating oil, and than cut it in half with a band saw. A majority of the bolt did not have penetrating oil even touch it. That is why I say it is semi effective. If the fastener is only semi rusted through than it will probably help. (I'll probably receive some hate mail on that one, but that is my opinion)

Okay lets talk removal techniques.

When a fastener does not immediately unscrew.
1. spray penetrating oil on it. (yes I'm not a huge fan, but in some cases it works just fine)

2. Do not just start prying on it counter clockwise with full force (it does have right hand threads on it.......?) Work it gently both ways. The reason why it is stuck is it's corroded or the threads are gauled. You need to bust the rust free. That is why I say both ways. Tapping on the end of the faster head with a hammer could possibly help. My old shop foreman tapped on the fastener and housing that it was stuck in, and coincidence or not it sometimes worked. If the threads are gauled the back and forth movement allows the threads to flex and expand. Remember when gauling has occured there are "chunks" of the opposing thread stuck on the fastener. These "chunks" will have to come out with the fastener. The only way to do that is to stretch the threads.

3. I'm not a huge fan of impact wrenches. If you do use one make sure you start with it on a low setting. Work it both ways, and bump up the power as you go. It's pretty easy to twist a head off with one.

4. Still doesn't come out. Grab a welder and some nuts. Welding the nut on is something that you must really concentrate on. Make sure that when you weld on that you have good bond between fastener and nut. It's really easy to fill the nut in, but not get any on the fastener. What makes this technique a good one is that the fastener becomes very hot. The housing that the fastener is in does not become nearly as hot. This difference in expansion can bust up the rust. You may have to weld nuts on a couple of times. Once again when you start to unscrew it be gently and work it both ways.

5. Another usefull technique is the heat and quench method. We do exhaust manifold all the time with no cracking. Start by heating up the fastener and the area around the fastener. It needs to be HOT. Once it is barely glowing red quench it in a bucket of water. As the material is heated it expands, and the second it hits the cold water it shrinks. This movement breaks up the corrosion. Most of the time I can just about unscrew it by hand.

6. Drilling the fastener out. This is one of the last techniques that I try. One of the biggest mistakes that are made is that they start the hole off center. I can not stress how important it is to make sure that it is in the center. If it is off center than your drilled hole is going to touch your threads on one side, but not the other. You need to center punch you fastener really really really close to center. Start drilling with a small bit, and work your way up to a size that will be just shy of your threads. Work your way slowly up to the threads. If done correctly you should be able to use a pick and clean out the threads. This is pretty difficult to do. If you can put the part in the drill press and clamp everything down to the table will help.

7. What if the bolt is broken off down inside. Well....... that sucks, but it can be done. The only way to get it out in your garage is by welding down inside the hole and building the bolt up till you can get a nut on it. This is not an easy technique. Sometimes if it is shallow you can use a wire welder. If it is deep than a stick. You can not and I repeat you can not get slag on the threads or you shot yourself in the foot. If you do not feel comfortable with it do not do it. Try drilling it out.

8. When all else fails drill it out and helicoil it. There are quite a few different products out there that can be used to repair a threaded hole.


Other things to be careful with.

1. Do not bang the end of a bolt with a steel hammer. It will mess up the end and if you can get a nut on it you might gaul the threads. Use either a soft head hammer, brass drift, or brass hammer.

2. When going together with old fasteners always check the threads. run an old tap in the hole, and a thread chaser on the bolt if it looks questionable. Use an old tap because rust will dull your new one down in a heart beat. Use a thread chaser instead of a die for the same reason. Thread chasers are cheaper. Some machine shops may even give you some old taps that are ready to be thrown out. I know I have that for customers



I think the key to any of these techniques is to be patient. Take your time and you will be rewarded. If you do not feel comfortable trying these methods than don't do it. Take it to a professional.

Okay that's all for now, but hopefully this has got other people inspired to reply with their own methods. Let's talk about this one, and help some people out.

[zymurgist]

Nice article! (IMG:style_emoticons/default/cool_shades.gif)

and (IMG:style_emoticons/default/welcome.png)

[underthetire]

(IMG:style_emoticons/default/welcome.png)

I would say if you get to the drilling out stage, try a left handed drill first. Sometimes that saves you a lot of work. As far as easy outs, depends on the quality of the easy out. I've had some junk, and some really good ones. Key on easy outs, don't pound them in to the hole, it will expand the bolt making it even tighter. If you have time, and a bolt or tap is broken in aluminum, you can get a acid from tooling houses that will eat only the steel. It takes days to do though.

Nice article

[codices]

Really appreciate that good article from someone who is in the business. Thanks.

Dave

[Brodie]

Underthetire you made some good points.

First left hand drill bits (I knew I forgot something) Very useful. They work especially good when fastener is not to tight. We have had some that were sort of loose in the hole, and they dug in and spun them out.

Second.....easy outs..... gasp, but you are right there is a big difference in quality. If you must buy a set I would buy the type that has straight up and down grooves. (I believe snap on sells some. My brother has a set. He uses them on rare occasions) The ones with the twist tend to dig in and tries to expand the fastener. Again if you must use them, make sure that your hole is in the center. Still wouldn't use them, but they do work for some people (In my humble opinion.

Third-acid-I don't know I've never tried it.

Thanks for the additional points

[underthetire]

Snap-on is a lot of hype on this kind of stuff. They don't make them they buy them and re-sell. Try Starrett or one of the good machinist brands, same quality at half the price. (IMG:style_emoticons/default/beerchug.gif)

Snap on is good stuff for automotive tools.

[jmill]

Good article. I have also seen busted exhaust studs melted out of a cast iron block with an oxy/acet torch. Doesn't work well with aluminum.

[Brodie]

jmill, I imagine that you could torch out a bolt. For those of you who don't know. It's almost impossible to cut cast iron with a torch. Just don't get the threads in the cast iron too hot because you could melt the tips of the threads off.

Underthetire, I'll agree with your views on snap on. Starrett is a top notch company, and I use their measuring equipment all the time.

[yeahmag]

I have only had easy outs cause pain.

[Brodie]

I was talking to my brother about the use of easy outs, and he made a really good point. If the bolt is stuck bad enough that you twist the head off how is a smaller in diameter, hard as heck easy out going to break it loose. (I'm still crusading to ban easy outs in America (IMG:style_emoticons/default/laugh.gif) )

[GeorgeRud]

Don't you still try some penetrants before the other options? I've generally had pretty good luck with Kroil, heating, tapping, and repeating as necessary. When it gets much beyond that, I like to leave it to the professionals.

Now, I don't get near as frustrated! The alternative is not to play with 40 year old cars!

[jasons]

That was a good read. Thanks! I know I've btdt with the easy outs. I've had them work, and I've had them fail. When they fail, it's almost catastrophic. I had to drop my motor when I broke an easy out inside an exhaust stud. I ended up sending the head to someone like you.

[abbott295]

My experience with easy-outs has been disappointing, too. I have come to the same conclusion about the likelihood of being able to get anything out that is stuck hard enough to break the original bolt, as your brother says.

I don't know that I've ever had anything break off with enough sticking out to try welding a nut on to it. It's always down inside, (Murphy's Law always applies.) And it breaks off jagged to foil me on drilling a hole on center.

But here's another idea I just recently read about in a farm magazine: Use a Dremel with a grinding stone on it to basically drill out the broken bolt. He wrote that he used up three of the grinding stones, but got the bolt out to where he could pick out the threads.

I haven't tried this yet, but my teener is waiting on a broken bolt that my son (who flipped it and therefore responsible for fixing it) hasn't been able to get out. I haven't gotten to it yet myself.

Many thanks for your contribution Brodie. This is good information. I nominate it for classic status.

[Brodie]

GeorgeRud, always start with penetrating oil first. It is my number one step. It works really good when the rust and corrosion is not too deep.

abbott 295, I guess I don't see why grinding the bolt out with a really small stone wouldn't work. (Providing that you're patient) I charge $60.00/hr and I don't think my customers would pay for that.


Great comments guys!

[Van]

Good stuff - can I post it on another forum?

I've had machine shops EDM out broken taps for me.... Pain in the butt, though.

Personally, I've had the best luck with welding a nut onto the broken bolt. I've used that method dozens and dozens of times.

[Brodie]

Van,

There are basically two kinds of EDM (Electro Discharge Milling) Sinker and Wire
It uses electricity and some form of dielectric fluid. I have a wire EDM and it works great for taking out broken taps on parts with a through hole. You have to be able to thread a .010" dia wire through the hole for it to work. Sinker is usually used in removing bolts

Check out EDM at Wikipedia for more info. I would provide a link, but I can't remember if that is allowed to do links in this forum. (Some of you gear junkies might be interested in the technology)

[Bartlett 914]

Good thread. I thought I would mention about penetrating oil here. First WD40 is not penetrating oil. This is an often made mistake. I believe I read here on the World a thread about penetrating oils. One oil was a mixture of acetone and ATF. I haven't tried this but the next time I need penetrating oil I plan on doing it.

[Brodie]

Bartlett 914, you are correct WD40 is actually a water displacement material. Hence the WD in the name. I can't remember, but for some reason I think is was developed for Nasa years ago. It's a great spray to have when you get condensation in your distributor cap. Spray a little in and that takes care of the moisture. I haven't tried that receipe of ATF and kerosene. There are about a million different penetrates. I even heard wintergreen oil works good. A guy brought in stuck cylinder from an old stationary engine and it smelled like christmas trees. Use whatever brand that you like!

[Brodie]

I'm adding another comment. It may seem stupid, but I had one today for a guy. When you use an allen wrench on a allen head cap screw make sure you have the hole entirely cleaned out. My customer had it in about 1/8 of an inch and stripped the hex out. We cleaned out the hole, and it unscrewed without any help.

So, to sum it up make sure that your fastener's head is cleaned out. Use the proper size screwdriver, wrench, etc. This may seem stupid, but it cost a guy about $8.00 today.

[bandjoey]

THIS NEEDS TO GO IN THE CLASSIC THREAD! Great information. Been there and done that with old bolts. (IMG:style_emoticons/default/biggrin.gif)