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.