Each time, approaching a mechanism that has long required inspection and maintenance, the owner disappointingly scratches the back of his head. Outside, the mechanism, as a rule, is already pretty spoiled by rust, and for sure all the connections are firmly seized. And so every time, before unscrewing the attached bolt. He can beat off the whole hunt for work!
And this is what happened. When tightening the bolt, the necessary tightness was not achieved, moisture entered the
threaded joint , and the reaction of water with iron in the presence of oxygen gave hydrated iron hydroxide, i.e. rust. She clogged the thread, the connection jammed. Well, and
how to unscrew an attached bolt if the connection has not been untwisted for years?
For starters, you can try to dissolve the rust. It does well glycol - a substance contained in antifreeze or
brake fluid. A moistened rag is placed on the stuck thread, the glycol will penetrate the rust, loosen it, and it will immediately become easier to unscrew the rusted screw.
Kerosene also penetrates well into the micro-gaps of the thread, as well as the white spirit solvent. Therefore, craftsmen from car repair shops in difficult situations like to use the WD-40 aerosol, half consisting of white spirit. To better penetrate the thread, you can lightly tap the head of the bolt with a hammer. Wait no more than 10 minutes.
And there is, as it were, a scientific way, how to unscrew an attached bolt. Around the head of the bolt you need to build a rim of plasticine or wax, put a little zinc inside and pour sulfuric acid. She won’t have time to eat the fasteners, because she will immediately attack the rust and, reacting with zinc, will begin to restore iron on the surface. A chemical reaction will literally clean the rust from the thread.
If it does not work out at all, you can resort to heating the bolt, then a gas torch (or soldering iron) is required. Heated bolt to about 230 degrees should cool. During heating / cooling, the changed geometry of the metal will destroy the rust so much that the threads are freed for the penetration of liquid lubricants. And then there should be no problems with how to unscrew the bolt.
When unscrewing, the hand should have a high-quality, reliable and proven tool. Of course, not made in China. In this case, open-end wrenches are ineffective - get the bolt heads crumpled by them and knocked down hands from breakdowns. Use
ring spanners and heads. Unscrew back and forth, swinging, as if
cutting a thread or pulling a stuck car out of the mud. In this case, the penetration of the lubricant into the thread will increase.
There are also more radical and extreme ways how to unscrew an attached bolt. First, hammer the head of the bolt on top with a hammer - this will disrupt the structure of rust. Then, using a chisel or a strong screwdriver and a hammer, knock alternately all the faces of the head, directing blows along the axis of rotation. In the vast majority of cases, the stubborn bolt should succumb and twist.
And the last one. When you tighten the bolt again, please do not forget about
graphite grease, solid oil or motor oil. Then the thread for many years, neither corrosion nor oxides will not be scary.