I often come across screws that just won't budge with a manual screwdriver or even a driver bit in a drill. They are of different screw types and heads in a variety of different materials. What are some techniques I can use to try and remove them?
Twist in the proper direction
Are you turning the right way? Remember, "Righty tighty, Lefty loosy" (which never made sense to me). Most screws are right-handed threads, so you'll turn them anti(counter)-clockwise to remove them. In some situations left-hand thread screws are used (usually to prevent screws from loosening due to rotational forces), so you'll actually have to turn the screw clock-wise to loosen it.
Sometimes tightening the screw very, very slightly, can loosen it up enough that it can be removed.
The first thing to try, is simply to apply more inward force while turning.
- Use a screwdriver with a head that fits snugly in the screw head.
- Put the palm of one hand on the back side of the screwdriver handle, and wrap your other hand around the handle ready to twist.
- Push the screwdriver as hard as you can with your back hand into the screw, and twist with your other hand.
If you are using a screwdriver with a hexagonal or square shaft, you can grip the shaft of the screwdriver with an adjustable spanner (wrench) or vise grips. This will allow you to exert more torque, and may put you in a better position to push the screwdriver harder into the screw head.
Sometimes screws seize up due to rust, or other debris. Soaking the area with penetrating oil, may free up the screw enough for you to remove it.
- Apply a liberal amount of penetrating oil to the area.
- Allow the oil to soak in for 5-10 minutes.
- Try to remove the screw (by conventional means, and using the technique above).
Rapping, Tapping, and Banging
If both methods above have not worked, giving the area a sharp tap with a hammer might break the screw free.
- Hit the screw and surrounding area with a series of sharp taps with your hammer.
Remember, you're not trying to knock the screw into next week, you just want to loosen it up (though there are situations where you'll have to give the piece a healthy whack).
For really stuck screws, you can use a manual impact driver.
- Attach a bit that fits snugly in the screw slot
- Set the driver to spin in the proper direction (this process varies from tool to tool, but most commonly, you'll compress the driver and twist).
- Place the driver on the screw, and hold the driver as straight as possible (keep you hands away from both ends of the tool).
- Give the back side of the driver a whack with a hammer (a rubber mallet or non-marring hammer is good for this).
- Repeat until the screw starts to twist (most impact drivers have to be "reset" between strikes, so don't forget to reset the driver before whacking it again).
- Once the screw is freed up, use a regular screwdriver to remove it.
This may not always be the best tool when working with sensitive electronics or delicate equipment, but it's very useful for removing stuck screws.
If you still cannot remove the screw, as a last resort you can drill the screw out.
- Select a drill bit that is just smaller than the shaft of the screw you want to remove (you may have to guess if you can't see the whole screw, but you can always go bigger later so start small).
- Place the bit in a drill.
- Place the tip of the bit in the center of the head of the screw.
- Drill until the screw comes free, or until you think you are deep enough.
- If the screw did not come free, switch to a slightly larger bit and drill again.
This is a last-ditch effort, and will destroy the screw (and possibly the threads in the hole, if not done correctly). Use this technique only as your last resort.
Remove the screw, and everything else in a 20ft. radius.
- Place the charge on the screw.
- Light the fuse.
- Run like hell.
- Cover your ears.
- Bask in destructive glory.
It's a good idea to film the explosion using a high-speed camera, so you can watch it over and over again in super slow-mo.
Abrasive paste as sold in car repair shops to use when grinding in valves in cylinder heads is great for screw heads that are 'worn'. Place a small dab on the screwdriver head before trying to unscrew the item. The friction from the abrasive in the paste will help the screwdriver 'grab' the worn screw slot..
If its metal on metal you can try heating the area or cooling it with ice. Metal expands and contracts with temperature change (works great on spark plugs too!).
For screw heads starting to strip, a piece of bicycle inner tube or rubberband between the head and driver bit helps it from stripping further.
For screws that held the original hinge in an old wood door, and would not budge, even with the advice above, I aimed a hair dryer at the screw for a few minutes (thinking that perhaps the wood was damp and that was holding the screw in; could also have been something about heat since I often run hot water over stuck screw tops). Anyway, it worked, with only 2-3 minutes per screw of heat.
I have just finished renovating an outdoor furniture set. This involved removing and replacing about 180 wood screws. The things I found that worked best are:
- Clean around the screw head as much as possible, to free it up from anything around it. Wood screws can become embedded, and the wood covering them hardens over the years, especially if oil/varnish/paint covers them.
- Use a tight fitting driver. My screws were square drive, and I found a lot of variation in available bits for my electric screw driver. Some were a bit loose, and tended to "cam out" when torque was applied, and damage the screw, reducing chances of removal. Price is not a good guide to how well the bit fits.
- I used Drive Grip, produced by Vibra-Tite. Its a friction paste, and really does help the bit grip the screw. Its not good enough to make up for a loose bit though.
- Use a high torque screw driver. The one I found best was s drilling brace with an electric drill driver bit attached. This can provide a very high torque to the screw, and with the Drive Grip, you have to be careful not to snap the screw.
- The process - Add a drop of Drive Grip to the head of the screw, seat the driver by tapping it into the slot, apply gentle torque, starting anti clockwise (out) and if there is no movement, reverse the torque. You should be able to see some movement in the screw head. The first movement might be torsion of the screw shaft - the head moves a little with the driver, but springs back to the initial position when the torque is released. This might be a sign you are getting somewhere, but is often a sign that the lower end is really rusted, and tight. If you don't mind snapping the screw, apply more torque and it will either come out or snap. In my case, I could separate the pieces of wood without damage once the head was off, so that's what I did. The snap usually occurred between the head and the thread, so I could work it out with vice grips. I had more success with soaking it in oil etc. at this stage than when the head was tight against the wood. In 4 cases I couldn't move the remains of the screw with vice grips, and ended up with the screw snapping again. Once the nub was too small to grip, I ground it off flat, and managed to realign the replacement screw into the same position on the top board, and miss the remains of the screw, so there was no outward sign there was a piece of old screw left behind.
- There were a number of times when the screw head was so damaged even my best drivers would not fit tightly, and applying torque simply rounded the drive hole in the screw head. I drilled these out. Modern screws are made of hard steel, so this turned into an exercise in drill sharpening. I used a final drill bit about 0.5mm larger than the screw shaft, so the boards separated as soon as the drill cut through the head, and the shaft could be removed with vice gips.
Sometimes cutting a new slot for a larger screwdriver in the screw head is all that's needed to get a stuck screw out. A hacksaw, file, or moto-tool with a cutting bit, can all be made to work in some circumstances. Cutting too deeply, or trying this on too small a screw can leave you with half a screw-head when you apply torque.
I have had to pull up the decking above my living room ceiling to chase a few leaks over the past couple years. The screw head are 4 points. slowing being replaced by 6 points, because the 4 points have been stripping. When they do strip, and if they did come partially out, I just slip the drill chuck over them, tighten it down, and unscrew them like that. Works very well. If the screw stripped before the screw started coming out, I drill straight down on the head with a bit slightly larger than the head to remove the head, oull the board up over it, and then use the drill chuck to remove it.
- Use the hammer at will.
- After breaking the concerned parts (and eventually some of the involving wood...) and getting rid of screw's head (the remaining can stay in its place...), use generously epoxy glue.
- Go straight to the closest mirror and admire the face of Einstein after creating the Theory of Relativity: everything is relative.