Unscrewing a Stuck or Stripped Nut: The Guide

Never hide the truth: it's sure to have happened to everyone to find themselves in front of a stripped or rusty bolt that refuses to unscrew. Even though we are used to heavy mechanics and drilling work, sometimes it is these inconveniences that put us to the test. Like when we need to extract a locked bolt. What to do in these cases?

Do we aim for force operations trying to cut or break the metal? Certainly, we may be tempted to work in this direction, but it's better to avoid it: sometimes we work in tight spaces and we cannot damage the surrounding structures.

There are other methods that allow you to unscrew a stuck, rusty or possibly completely stripped nut. Let's first try to understand the causes of this unpleasant and problematic condition, and then find the right solution.

Always Use the Right Wrench

The reason the bolt became stripped: inadequate tools were used to unscrew and screw. Maybe you only had oversized wrenches available, maybe only one size, or standard pliers. Result? The bolt's profile is now smooth. This prevents normal tool use and, as a result, the connected bolt cannot be unscrewed.

Before rushing to fix it, however, try to use a star or pipe wrench to try to unscrew the stripped bolt: they offer more bearing surface so they are more effective. If the bolt is completely smooth and you have space you can try to unscrew with a pipe wrench: the leverage mechanism is very effective. Also, robust and serrated jaws are designed to grip metal without handholds. Just like a stripped bolt.

Try to Oil the Bolt That Won't Unscrew

Why did this mechanical element decide not to unscrew? The answer is simple: probably rust has attacked the mechanism. So the thread and bolt have become one. That's why there are considerable difficulties in opening attempts: you can't unscrew the bolt because everything is stuck. Solution? Use some spray lubricating oil to dissolve the oxidation. At this point, use an appropriate wrench and the right leverage.

Create a Notch to Unscrew with Hammer and Chisel

An old trick from the workshop. If you have a rusty or stripped bolt that won't unscrew, you can try this trick: with a metal blade create a deep enough notch, then use a chisel or screwdriver and a hammer to drive counterclockwise. This way you can solve the problem by only damaging the nut.

Remember that if it doesn't move, you can use a heat stripper or heat gun to heat the nut or the surrounding area. The heat makes the outer metal expand, loosening the grip. Try to unscrew while it's hot but always watch for the presence of any flammable liquids.

Sockets for Extracting Damaged Bolts

These are special sockets that have reverse helical grooves inside. The more counterclockwise turns to unscrew, the more the inner cutting edges bite into the rounded bolt head, locking and unscrewing it. It is the best investment if you often have to deal with the problem of stripped bolts in a mechanical workshop.

Destroy the Bolt and Use the Extractor

Last solution: cut the bolt longitudinally, so on the side. This way you completely eliminate the problem. Less invasive solutions involve the use of specific nut splitters that wrap around the bolt and score it with a punch by tightening the tool more and more until the metal is destroyed.

You can also use a saw or a flex disc to speed up the work. This way, however, the bolt will not be recoverable but, above all, you risk ending up with a stuck bolt in the base. So still screwed into the metal or wood. In these circumstances you can use the extractors for broken bolts (here is the dedicated guide). There are also Krino models, and the use is simple: you drill the bolt, screw counterclockwise and then use a wrench to unscrew.