Remove a Stripped Screw

If the screwdriver bit keeps slipping against the screw head, you'll need to increase the friction or torque. There are many simple ways to get a better grip on the screw using household materials. You'll need a specialized tool for truly stuck screws, but most of these are fairly cheap and widely available.

Steps

Using a Screwdriver

  1. Maximize the grip strength. If you can still grip the screw head with a screwdriver, try one last time to remove it by hand. Follow these instructions first to maximize your chances:
    • If the screw is fastened to metal, spray on penetrating oil and let sit at least fifteen minutes.[1]
    • Use the largest manual screwdriver that fits your screw.
    • If possible, grip the screwdriver handle with a wrench to get more leverage.
  2. Add material for extra grip. If the screwdriver keeps slipping out of the stripped hole, cover it with a small piece of material that gives extra grip. Press this into the hold with the screwdriver and try again. Here are some options:
    • Use-a-Rubber-Band-to-Unscrew-Stripped-Screws, cut to form one band
    • A piece of steel wool
    • A piece of green abrasive from a kitchen sponge
    • Duct tape, with the adhesive side against the screw head
  3. Tap the screwdriver into place with a hammer. Tap the screwdriver in gently to avoid breaking the screw head. Skip this step if you are working with a fragile object.
  4. Push down hard as you rotate. Place your palm against the end of the screwdriver, with your arm directly behind it. Press directly down into the screw with your full forearm as you rotate the screwdriver.
    • If the tool you are using is slipping, stop using it immediately. Further slippage will only continue to wear down the screw head and make it harder to remove. Definitely be sure you are going in the correct direction for removal, which is usually--but not always--counterclockwise ("lefty loosey, righty tighty"). Pressing down hard as you are unscrewing will help prevent slippage.
  5. Heat the area. If you can heat the screw without damaging the object the screw is attached to, this will often loosen the threads. Apply a heat gun or propane torch to the screw, moving it constantly to avoid overheating. Once it is hot enough to sizzle a drop of water, let the screw cool, then try again.[2]
    • This works especially well if the screw has been set in place with a bonding agent.
  6. Cut a flat-head notch with a dremel or hacksaw. If your screwdriver still can't get a good grip, cut a notch into the screw head. Insert a flat-head screwdriver and attempt to turn the screw.[3] You can combine this with any of the approaches above.

Using an Impact Driver

  1. Get an impact driver. An impact driver is a manual tool that drives a screwdriver bit further into the screw using a weight and spring. This works well on sturdy construction, but may damage electronics or other sensitive equipment. If you're concerned about damage, avoid cheap models with a stiff spring, since these require forceful hammer blows to work.[2]
    • A powered impact wrench is not recommended, since the excessive force could damage the surrounding material.
  2. Set the impact driver to loosen screws. Some models have a switch. On others, you set the direction of the turn by twisting the handle.
  3. Hold the driver in place. Fit a drill bit of the correct size to the end of your driver. Place it in the screw and hold the driver in place at a 90º angle. Grip the driver at its midpoint, keeping your hand clear of the end.
    • The bits that came with your impact driver are often extra-hard, which makes the process easier.[2]
  4. Strike the end with a mallet. Tap the end of the driver sharply with a heavy mallet. A rubber mallet helps you avoid scratching the driver.
  5. Check the driver direction. Some impact drivers jar out of position after each strike.[4] Set it back to "loosen" if you need to.
  6. Repeat until the screw is loose. Once the screw comes loose, use a regular screwdriver to remove it from the hole.

Using a Screw Extractor

  1. Get a screw extractor. If the screw head is worn but intact, purchase a screw extractor. A typical extractor is essentially a screwdriver bit made of extra-hard metal, reverse threaded right at the tip. This is one of the most consistent ways to remove a stripped screw, but it does require caution. If the extractor breaks off in the screw, it may require a professional to finish the job. To reduce the chance of this happening, choose an extractor no more than 75% of the diameter of the screw shank (not the head).[5]
    • For Torx or socket cap screws with an exposed cylindrical body, use a multi-spline extractor. This fits over the head of the screw, and engages it with splines (teeth) on the inner surface. Instead of following the instructions below, tap this type of extractor gently into place, then turn with a socket wrench.
  2. Punch a hole in the center of the screw head. Place a center punch on the exact center of the screw head. Strike the end with a hammer to create a dent for your drill.
    • Wear eye protection to protect yourself from flying shards of metal. Keep them on throughout this process.
  3. Drill a hole into the screw head. Use a drill bit designed for hard metal. The screw extractor should have the drill bit size stamped somewhere on the tool. Drill slowly and stabilize it with a drill press if possible. Start with a hole ⅛ to ¼ inch (3–6 mm) deep; going too far may break the screw.[5] It helps to start the hole with a small drill bit to give the larger one a place to grip.
  4. Tap in the extractor with a brass hammer. The extra-hard metal of the extractor is brittle, so an iron or steel hammer could break it. Tap it in until the extractor has a firm grip on the walls of the hole you drilled.
  5. Turn the extractor carefully. If the torque is too forceful or uneven, the extractor may break, leaving you worse off than before. A tap handle that fits snugly over the head of your extractor is by far the safest way to remove the extractor and attached screw. The drilling should have loosened the screw, so you can often remove it without much force.[2]
    • Some extractor kits come with a nut that fits over the extractor head. Grip the nut with two wrenches about 180º from each other, for a more equal torque.
  6. Heat the screw if it won't come out. If the screw doesn't budge or you're concerned the extractor might break, remove the extractor. Heat the screw with a torch, then drip paraffin wax or water on it to lubricate the threads. Try the extractor again once the screw has cooled.[6]
    • Take care not to damage the surrounding material. Even when working with metal, it's best to stick to heat guns or propane torches. Move the torch around the screw constantly to avoid heating any one spot for more than a second at a time.[2]

Additional Methods

  1. Attach a nut to the screw with epoxy. Find a nut that fits snugly around the screw head. Bond them together using a two-part metal-to-metal epoxy, often sold as "weld bond." Wait for the epoxy to cure as directed on the label, then grip the nut with a socket wrench and rotate.
    • If you don't have a nut the right size, you can adhere a smaller nut to the top of the screw head. This will not provide as much leverage.
  2. Drill out the screw head. Breaking the screw usually relieves pressure on the screw shaft, making it easier to pull out — but if it doesn't work, you've eliminated most other options. Choose a drill bit slightly larger than the shaft of the screw, so the head detaches completely when you drill through. Start with a center punch to make a hole in the exact center of the screw, and take care to drill directly through the center.[2] Once the screw head breaks off, grip the screw shaft with locking pliers and rotate counter-clockwise to remove.
    • If the screw head isn't flat, file it down or grind it with a dremel and a pointed grinding stone attachment. Center punch and drill once you have a flat surface to work with.
  3. Hire a professional. If all else fails, hire a machine shop to remove the screw using electrical discharge machining (EDM).[2] This may be your best option if you used a screw extractor that broke off inside the screw.



Tips

  • If you can access the rear side of the object, see if the screw shaft is protruding through it. If it is, grip the end with pliers or a hex wrench and rotate out from below.
  • Make sure you are rotating in the correct direction. The screw may be reverse-threaded, in which case you'll need to rotate clockwise to remove it.
  • If the hole left behind is stripped, there are several ways to repair it:
    • Use-a-Tap. For extra strength after tapping, apply loctite to the hole and install a heli-coil insert.
    • Screw a larger, self-locking screw into the stripped hole.
    • Use a nut and bolt instead. If fastening metal objects, you can weld the nut to the metal to create a stationary, threaded mount.

Warnings

  • Metal burrs caused by stripped screws can cause injury or mechanical malfunctions.

Things You'll Need

  • Screwdriver
  • Screw extractor, screw extractor bit, or screw extractor kit. ($1-$20 in your local hardware store)
  • Socket wrench
  • Power drill
  • Metal-drilling drill bit
  • Eye protection
  • Work gloves
  • Hammer or mallet
  • Impact wrench
  • Screw extractor
  • Locking pliers
  • Duct tape, rubber band, steel wool, or abrasive pad

Related Articles

Sources and Citations

  1. ↑ http://www.familyhandyman.com/automotive/how-to-remove-a-stuck-screw/view-all
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 http://www.motorcycle.com/how-to/how-to-extract-stuck-screws-3440.html
  3. ↑ http://www.todayifoundout.com/index.php/2010/02/the-12-best-ways-to-remove-stripped-screws/
  4. ↑ http://diy.stackexchange.com/questions/16263/how-can-i-remove-a-really-stuck-screw
  5. ↑ 5.0 5.1 http://www.naturalhandyman.com/qa/qastrippedscrew.html
  6. ↑ https://books.google.com/books?id=Yn9F0RhJ0EkC&pg=PA62
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