A chain whip is a tool used in bicycle repair. Most chain whips are similar in appearance, usually consisting of a length of bicycle chain affixed to a rectangular metal rod. The chain is wrapped around the sprocket teeth on a freewheel cassette to prevent it from rotating backward while the central lock ring is removed. It may also be used to unscrew threaded cassette sprockets. A chain whip's handle provides the required leverage for both operations. Because of the relative simplicity of this tool, you can make your own on the cheap.
Fill a small plastic bowl halfway with solvent. Paint thinner, isopropyl alcohol or orange degreaser will work well. Place the old bike chain in the bowl and allow it to soak for an hour.
Scrub the chain clean of remaining grease and dirt using an old toothbrush. Rinse the chain clean with a garden hose and dry thoroughly with a paper towel.
Shorten the chain to a total of 40 links using a chain breaker tool. Count out 40 links from the beginning of the chain and lay the 41st link across the top of the tool. Rotate the lever until the tool begins to push out the securing pin from inside the link. Remove the chain from the tool and pull the chain apart.
Saw a 12-inch to 16-inch length from the 1-inch by 1-inch piece of wood. This will serve as the handle for your chain whip.
Orient the length of wood so that the grain is facing upward. To find the grain, look for the side which displays a visible pattern or texture. The nongrain side will be comparatively smooth and blank. The chain must be attached to the grain side, else the screws will be ripped out under force.
Lay the chain on the length of the wood so the spaces between the links are exposed. The top of the chain should be flush with the top of the wood, and the chain should be as centred as possible prior to attachment.
Sink a wood screw between the link about one inch down from the top of the wood. Move seven links down and sink another screw. Ensure that the heads of the screws are wide enough to anchor the chain.
Wrap the lower portion of the wooden handle with electrical tape to prevent slivers and improve the appearance of your new chain whip.
Ensure that the screws are firmly embedded before using your chain whip for the first time.
Use protective goggles during the chain whip's first use.