I was inspired to put this post together when searching for ways to remove a broken screw recently – there are so many different tricks that I thought it would be fun to collect them all in the same place. I have tried to put them in order of try-ability, with those that use tools you probably already have at the top.

First of all, are you dealing with a stripped screw or a broken one? A stripped screw is where the slots in the head have become worn and rounded so that the screwdriver can’t grip it and looks like this:

A broken screw is one where the head has sheared off, and looks like this:

If you have a broken screw then the techniques for dealing with a stripped screw won’t help you, so jump down to the methods for broken screws. On the other hand, if you have a stripped screw, then you can use any of the techniques on this page so just start reading.

Methods for stripped screws

Tap or heat the screw to loosen

The idea here is to loosen the screw so that you can use what little grip remains in the head to unscrew it. Tapping can help to free a seized screw, while heating a metal screw can loosen it by making the metal expand then contract. To loosen the screw by tapping, place the tip of a screwdriver in the screw head (as if you were going to turn it) then tap the butt of the screwdriver with a hammer. To loosen it by heating, place the tip of a hot soldering iron in the screw head and press down for a few seconds.

Drill a small hole in the centre of the screw

By drilling a hole just a couple of millimetres deep in the middle of the screw head, you can allow the tip of your screwdriver to go deeper in the head and get a little bit more grip. Use a very small drill bit that will work on metal.

Use a rubber band to get more grip

This one is simple; just place a rubber band over the screw head and unscrew it normally. The rubber can help to give just enough extra grip to get the screw to turn.

Use aluminium carbide or valve grinding paste

The idea here is the same as above – give the screwdriver a little more grip on the screw head. Just spread a little of the paste into the slots in the screw head and unscrew as normal.

Use a hammer to reshape the slots in the screw head

An unsophisticated trick :-) Seat the tip of a screwdriver in the screw head and whack the base of the screwdriver with a hammer. This is only likely to work on screws made out of soft metal (but hey, maybe that’s the reason they get stripped in the first place!)

Use a flat-head screwdriver on a cross-head screw

Sometimes a flat-head screwdriver can get a better grip on a stripped cross-head screw than the correct screwdriver can get, due to the way that cross-head screws are designed to “cam-out”. Use plenty of pressure to keep the screwdriver seated.

Use a screwdriver that's too big

Very similar to the trick above. Instead of using a flat-head screwdriver, use a cross-head screwdriver, but pick a size that’s too big for the screw. If the slots have been worn, this can often give a better grip than using the correct size.

Use a steel punch to hit the screw off-centre

This is only likely to work on screws that have a large head. Take a small hardened steel punch and use it to hit the screw off-centre so that it rotates anti-clockwise. This sometimes works to start a screw moving; as soon as it’s loosened, move on to one of the other methods.

Methods for broken screws

Grip the screw with a pair of pliers and turn it

If the screw isn’t secured too tightly, and there’s enough of it protruding, you may be able to get enough purchase with a normal pair of pliers to remove it. Be sure to clamp the screw in the sample place with the pliers each time you grip it so you don’t round off the screw.

Of course, the more leverage you can get to grip the screw with the better, so if you’ve got a pair of pliers with long handles and an adjustable jaw, then use them. And if you are lucky enough to have a pair of locking pliers (AKA vise grips, vice grips, or mole grips, depending on where you live) then you can use them to apply much more pressure and to clamp down on the screw while you turn it.

Clamp the screw shaft in a drill chuck and turn slowly

The chuck of a drill is designed to hold the shaft of a drill bit securely, so it often also does a pretty good job of holding the shaft of a broken screw. Tighten up the chuck of the drill as hard as you can around the screw – you will need both hands for this so get someone to help by holding the drill in place as you do it. Don’t plug the drill in until you’ve finished clamping the screw, and make sure it’s in reverse before you turn it on. Any cheap drill should work for this, or you can also use an electric screwdriver if it has a chuck. Don’t try this trick with a rotary tool like a Dremel – they are designed for high-speed, low-torque so will be useless (but if you have a Dremel, see the next method!)

Use a rotary tool to cut a slot in the screw

If there is enough of the screw protruding above the surface it’s screwed into, you can use a Dremel or other rotary tool with a cut-off bit to cut a slot directly into the shaft, which you can then unscrew with a flat-head screwdriver. Make the cut as straight as you can. If there is plenty of shaft visible, then you can do the same with a hacksaw, but it’s much trickier – you’ll need a very narrow blade and a steady hand.

Use epoxy to glue a nut onto the end

Two-part epoxy glue forms an incredibly strong bond, so you can use it to glue something onto the end of the screw that will give you enough grip to turn it. Use a type of epoxy designed for metal – J-B Weld is the strongest. The best thing to glue, if you have one, is a nut that just fits over the head of the screw. Position the nut over the head of the screw, then mix up the glue and use it to fill the gap between the nut and the screw. Be sure not to accidentally glue the screw to the surface that it’s stuck in! Wait for the glue to cure then use a spanner or socket to unscrew the screw using the nut.

Other type of glue are not strong enough for this trick, so don’t bother trying – you will just create a mess!

Weld a nut onto the end of the screw

A similar approach to number 4, but (if you have access to a welder) a much quicker one. Weld the end of the screw to something solid which you can use to grip it – a nut is perfect.

Use a screw extractor

This is bottom of the list because it involves buying a special bit of equipment – a screw extractor set. However, it really belongs at the top because it is the quickest, most reliable solution. Screw extractors have a left-handed thread, which means that you put your drill into reverse and then start drilling into the broken screw. When the extractor has embedded itself in the screw, the left-hand rotation will neatly unscrew it. If you’re going to the trouble of buying a screw extractor, then you might as well buy a set, because (1) you won’t have to try to guess which size you need and (2) you’ll have the correct tool on hand the next time you encounter a broken screw!

Subscribe to articles from the diy category via RSS or ATOM


comments powered by Disqus