Remove a Woodruff Key

A woodruff key is installed in the hub of a pulley or gear so that the pulley or gear does not slip off the shaft it is attached to or spin freely. These keys are found in motorized devices such as lawn mowers, motorcycles, and cars and are held in place by a threaded fastener. By removing a key, you can remove and modify other parts of your vehicle or replace a bad key to improve performance.[1]

Steps

Removing Keys by Hand

  1. Apply penetrating oil. Put this directly onto the pulley and shaft area to loosen any corrosion that will make the pulley hard to move.Those that come in spray bottles are handy and will still be effective for getting into and breaking up rust on metal.
  2. Remove the threaded fastener. This holds the pulley in place and can be undone with a tool such as a crank remover or wrench. If the threads are damaged, more tools and methods will have to be utilized, such as pliers.[2]
  3. Clean the shaft. If there is any rust or dirt on the shaft, lightly sand or brush it. The hub of the pulley usually is fit well to the shaft, so the debris can prevent a loosened pulley from sliding off.
  4. Loosen the pulley nut. Do whatever you can to stop the pulley from turning, then use a tool such as a socket or ring spanner on the nut until the pulley can be removed.[3]
  5. Pry off the pulley. Place a pry bar or a large screwdriver behind the pulley, if there is a surface behind it to use as leverage. If not, you can try striking the back of the pulley with a hammer while applying pressure with the pry bar or screwdriver.[4]
    • Use a soft-faced hammer to avoid damaging the components. If you use a normal hammer, hold a wood block against the fastener and shaft.
    • Tap the pulley shaft with the hammer. Don’t use too much pressure. For steel hammers, insulate the shaft, nut, and bolt before striking.
  6. Take out the key. On the now freed pulley, look for a semicircular piece inset into the shaft. This is the Woodruff key. Grip the sides of the key with pliers and remove it. If pliers don’t work, try to wedge it out with a small screwdriver. These keys are delicate, so force can easily damage them, but keys are easily and cheaply ordered in hardware and auto part stores or online and replaced. Remove any shredded key bits in the machine so they don’t cause damage later.[5]
    • You can try tapping a nail on one end of the key, drilling into the center of the key and removing it with a nail, or even heating the key up with a blowtorch and letting it cool repeatedly to loosen it.
    • Remember that damaging the key is a far better alternative than damaging the shaft or other part around the key.

Using a Gear Puller

  1. Select the right size. These claw-like devices come in different sizes. You can use measuring tape to find out the diameter of the pulley so that you can buy or rent one that expands to fit over the pulley.
    • You’ll need an appropriate socket wrench to adjust the forcing screw on the gear puller.
  2. Fit the arms. Once the gear puller is set, the center bolt should engage the pulley shaft in proper alignment to prevent slippage. Adjust the arms so that the puller’s jaws are set at about right angles against the pulley or gear.[6]
  3. Tighten the forcing screw. Use the socket wrench to tighten the screw at the end of the gear puller until the screw touches the pulley shaft. Continue turning until the pulley can slide free.
    • You can strike the exposed end of the gear puller with a hammer to try to loosen the pulley.[7]
  4. Remove the Woodruff key. On the freed pulley, locate the semicircular shape in the shaft. This is the key and it can be removed by gripping the sides with pliers or wedging one end with a screwdriver. The key may be stuck. If that is the case, alternative and possibly damaging measures need to be taken. Remember to remove any shredded key bits.
    • Try tapping down on one end of the key with a hammer and nail. Another option is to drill into the center of the key and remove it with a nail.
    • Rapidly heating the key with a blowtorch and letting it cool can help loosen it.
    • Remember that these keys are cheap and readily available online or at hardware and auto part stores, so causing damage to it may be necessary. Damaging the parts around it is a more costly idea.

Tips

  • Lawnmowers have a "shear" key, which prevents damage to the crankshaft, located in the hub of the flywheel or magneto. These often cause the engine to refuse to run but are easily replaced when you learn how to remove them.

Warnings

  • Wear safety glasses when using a hammer to strike another metal surface or tool.
  • Use care using lubricating oils. They are often flammable and harmful to skin and eyes.

Things You'll Need

  • Wrenches
  • Prying tool
  • Soft-faced hammer
  • Penetrating oil
  • Gear puller, if needed

Related Articles

Sources and Citations

  1. ↑ http://www.scooterhelp.com/tips/engine/flywheel.old.vespa.html
  2. ↑ https://garage.eastwood.com/eastwood-chatter/10-tricks-to-remove-stripped-stuck-bolts/
  3. ↑ http://www.vw-resource.com/pulley_removal.html
  4. ↑ https://www.howacarworks.com/electrical-systems/removing-and-refitting-a-dynamo-pulley
  5. ↑ https://aylo6061.com/tag/morini/
  6. ↑ http://www.ebay.com/gds/How-to-Use-a-Gear-Puller-/10000000178758751/g.html
  7. ↑ https://www.ccohs.ca/oshanswers/safety_haz/hand_tools/gearpullers.html

You may like

Retrieved from "https://kipkis.com/index.php?title=Remove_a_Woodruff_Key&oldid=324655"