DEAR MIKE: I was adjusting the tracks on my garage door where they attach to angle brackets, and I came across a bolt that I could not loosen. Do you have any hints that might work? -- Dale W.
DEAR DALE: I have lots of hints that might work, but then again you may end up with skinned knuckles after the wrench slips.
When you have a bolt that is stuck, you probably go at it like a dog on its dinner. That is, you grab the head and hold it tight while you turn with all your might.
About the worst thing you can do is to use an adjustable wrench (aka crescent wrench) on a bolt head that won't budge. An adjustable wrench has a little play in the jaws, which gives it a unique ability to trash the head of the bolt. It can only grip the head on two sides, and using it aggressively will chew away the corners leaving a round head. Then you have problems.
Before you get really creative, try using a little heat. Actually you're going to use a lot of heat. Remember back in high school physics when the teacher explained that heat causes metal to expand? I don't, but that doesn't matter.
Get out the torch and hold it to the head of the bolt (this is only good if the bolt is in metal -- so keep all flammables away). Hold the tip of the flame to the bolt for about a minute and then let it cool down so that it is cool to the touch. Squirt some penetrating oil or WD-40 on the bolt (be careful since these are flammable). Next, take a hammer and bang on the bolt to loosen it. This will allow the penetrating oil to work its way down to the nether regions of the bolt and then you should be able to unscrew it.
If the head of the bolt has become rounded to the point where an open end or box wrench can't grip it, you can use either locking pliers or a large pair of Channellocks (groove joint pliers). I prefer the large Channellocks because you can get a large amount of leverage and set the jaws so that they crunch down on the head so it won't slip. You can also file two flat sides on opposite sides of the head so that you can get a wrench back on it.
To get the best possible grip on a bolt, use a socket and a ratchet. They also make something called a breaker bar which is just a long bar for increasing your leverage. You can increase your leverage by putting a length of iron pipe over the end of a ratchet. This will increase the amount of turning power at the head of the bolt but beware -- the extra force may shear off the bolt's head. Then life gets ugly.
Fortunately, there are products made to get your weekend back on track. One such product is a screw extractor. It is sold at hardware stores under the name "Easy Out." This baby looks like a fat drill bit but it is tapered. The kit comes with a hardened drill bit for boring a hole into the broken off bolt. Then you stick the extractor in the hole and turn it counterclockwise. The left-handed threads will jam the extractor into the hole and turn the bolt out.
If you have a bolt with a nut that won't come off, break out the hacksaw, which will cut off the nut so you can remove the shank of the bolt.
You can also use a tool called a nut splitter, which has a ring that fits around the nut and inside the ring is a tooth. You simply tighten this tool which forces the tooth into the nut and the nut splits open.
A hacksaw works great when the screw's slot for a standard screwdriver is mangled. You can saw a groove perpendicular to the factory slot and then use a screwdriver to back out the screw.
For larger screws or carriage bolts (they have no grooves or flat sides for gripping), you can stick two blades in the hacksaw, side-by-side, and cut a fat groove. This will allow you to use a larger screwdriver to remove the bolt. If it still won't come out, try holding the screwdriver down into the groove and turning the screwdriver with a wrench.
If you're lucky, you may be able to keep the skin on your knuckles.