First off let me give props where they are due, this idea was inspired largely by the instructable posted by mydian_nightshade called
Cheap bike rack. Please visit his piece to fill in any gaps on construction or to see what else can be done using this same process. My documentation was done without a step-by-step in mind so it is a little dicey, however the process is very simple and fairly self explanatory. So, lets get started.
Materials:
Ladies bike
1 2x4
Screws
Dollar Store LED flashlight
Stain (if desired)
Tools; Table saw, chop-saw (miter saw), chisel, drill, sander
The first thing I did was rip the 2x4 lengthwise on a table saw to get two 2x2 sticks. Next, you need to measure across the frame, starting a couple of inches behind the top-tube and extending out to the distance you want your rack to end. I decided to make a rack that would extend the length of the tire and came up with about 21 1/2 inches. Cut two sticks out of your 2x2s to the length you like. These are going to be the center pieces of your rack and they will sandwich around the frame. To achieve this you simply need to hold the pieces, one at a time, up the the bike frame at the height you want your rack to sit, and trace the frame onto the wood. Use a level to insure that your rack wont be tilted up or down when you are finished. This is the shape that you need to chisel out to fit the boards around the frame. If your tubes are 1" in diameter then you would cut each board to a depth of 1/2". (again, mydian_nightshade has a great example of how to do the chisel work
HERE It helps the stability of your rack if it is a tight fit, so it is better to err on the side of removing too little material and then fine tuning the fit from there.