How to make a simple chain whip for removing sprockets on a bicycle cassette. If you've got the materials knocking around then it's obviously cheaper that buying one.

Step 1: Gather Parts and Tools

For this chain whip you will need:

An old bike chain
Something for the handle, ideally a 1-1.5 inch wide by 5 mm thick flat metal bar/sheet. I cut a strip from a sheet of plastic I had lying around and it really didn't work. MDF or plywood might work but metal is your best bet.

Tools:
Chain breaker
Drill with 3.5 mm bit
Hacksaw/jigsaw
Hammer

Step 2: Prepare the Handle

Cut the handle to a length of 12 to 18 inches and smooth down the sharp edges.
Then drill three holes towards one end of the handle and approx. 7 mm from the edge, with a distance of 40 mm between the first and second hole and 10 mm between the second and third hole.

Step 3: Prepare the Chain

Break the chain into a 3 link section with open links and pins at both ends and a 7+ link section with an open link and pin at one end.

Step 4: Attach Chain to Handle

Line up the 3 link chain section with the first two holes on the handle and the 7+ link with the third hole. The chain breaker won't fit around the handle to close the links so use the hammer to knock the pins through. Et voila, one chain whip.