[blog:how to] Techniques to Remove Rounded Bolts
Last post, I accident rounded the head of a bolt while trying to remove my transmission. I've never NOT been able to remove a stuck bolt, and I thought I would share with you a few things I use to get bolts out.
Before we get there, lets look at how I ended up having to write this post first!
Here are the offending bolts. You'll notice there was a vary degree of "technique" that I employed to remove them.
If you're looking carefully, you'll notice that these are 6 pointed star shaped bolts, also known as "torx". They have increased torque capacity, but they utilize their own special tool sized with an E designation (E8 would be like an 8mm socket, just torxed shaped).
My dumbass on the other hand, decided who the fuck needed a special socket. So I stuck a standard 6 point "hex" socket on there and wailed at it with my 600 ft-lb rattle gun. It took a few wacks, but it got it off. This somehow validated my ego, despite knowing full well, that I was in fact, just lucky.
So I get on the second one and hit it a few times and it spun a bit . Great I thought!
I let my finger rip on the trigger and it spins through.....and doesn't stop. I rounded the head!
Like a true idiot, I got on the second one and did the same thing.
I knew better, pushed my luck and went over the edge! What now? Unfortunately, this isn't the first time I've done something like this, so I've learned quite a few tricks to bail myself out.
Here's some tricks to get the rounded bolt out.
I have to start with, I always apply a penetrating oil of some sort. You need every advantage you can get when removing a rounded bolt. Doing something easy like soaking it in penetrating oil certainly helps if there is even one small pathway for the oil to get in.
Technique 1
Use a lot of heat! If the part you are working on can tolerate it, applying heat to the part will allow it to expand,giving the bolt a better chance of breaking free. On steel, you can apply a considerable amount of heat without damaging the part, you don't need to get the part red hot, just hot enough to get it to smoke a bit. With most steel parts, I can give a minute to 2 minutes of heat, depending on the thickness of the part. For aluminum, I spread the heat out and try to heat it for 2-3 minutes. The aluminum dissipates heat much faster than steel does, so you have to heat a broader area to get heat to focus on a certain spot. Start by heating the outer ring for a minute and slowly focus in on the problem area.
Pro Tip: Since a bolt joins two parts together, always heat the end of the bolt. The head of the bolt pushes down on the first part, and the threads pull on the second part. Don't bother heating the head of the bolt.
Technique 2
Using a special extraction tool if possible is always a good idea, but those extraction tools are often bigger than typical sockets and may not always work. That's why you breakout the open ended master socket....the VICE GRIP. If you have a good pair of vice grips,(with nicer teeth than my old pair), you can attempt to grab the bolt and turn it. A good technique to do here is to strike the face of the bolt with a hammer to try and shatter any rust or any looseness out of the threads. Combining this with using heat as mentioned in technique 1 is HIGHLY recommended. Just don't heat it up with the tool attached to the bolt. You might forget and grab a burning hot tool.
Technique 3
Use a dremel type tool and cut a slot into it, so you can use either a screw driver or a chisel. In my case, I was working under a car, and I didnt have the right leverage to generate a strong hammer blow, so I can't show you that technique however, its nothing more than a bolt with the slash through it to make it behave like a flathead head bolt.
do any of you guys call it a minus, or negative head screw?
This typically won't work for me, and I use a secret trick that I discovered while swapping the clutch on my saab....
USE AN AIR CHISEL! An air chisel hits so rapidly that it likely spits out 30-50 strikes in a single second. The downside is that its difficult to control and it will absolutely DESTROY the nut.
You want to start by grinded down the bolt so you have a nice half moon. You then take an air hammer and set it on max PSI to get the most speed out of the tool. Then you strike the edge of the bolt. This usually gets the bolt out every single time. Its a difficult technique to master, but has always worked for me and now I'm sharing it with you guys.
Sorry for the blurry photos, my forearms were sore from holding up all the tools working on my back!
To summarize:
1. Use penetrating oil
2. Strike the face of the bolt with a hammer
3. Bite and turn it with a Vice grip
4. Use a lot of heat
5. Use an air chisel
Here are the bolts that I removed from the turbo of my previous car, a Saab 93SE.
TORN UP!
you forgot welding a larger nut on and then using that to take it out. I do that a lot when the bolt head breaks off, I just slide a nut over it and weld down inside the nut to make a new bolt head and turn if out with the new nut.
Great option! In some cases though, you cant fit the torch head to perform the weld (which was my case). But definitely one of the BEST options if you have the ability to weld!
Also if you round out the inside of an Allen head bolt. Pound a triple square in it and it will come right out. Works awsome
do you turn a socket around and just pound that into it? or do you have some kind of die device?
You just pound that star shaped part into the rounded out Allen head bolt. It will dig in and turn the Allen head bolt out.
Oh! I've done that before, but you'll need clearance for a hammer strike. Heating it up as hot as you can would help too. But at that point, I'm likely to have already smashed the snot out of the head that there isnt much left to "form".