Here is how to easily modify your existing steel rip fence to make easier rabbet cuts with your dado blades. The dado blade sits underneath the slot in the wooden fence, allowing you to make easier rabbet cuts.
You will need:
A 2x4 or there around piece of lumber
3 or 4 bolts, I used three 1/4" wide, 2" long bolts with 3 washers, nuts and lock washers
A table saw
A small, pointed object
Drill press or hand drill with appropriate bits, I used a 1/4" inch bit and a 3/4" bit
Step 1: Examine your rip fence
My rip fence came with 3 pre-drilled 1/4" holes in it. If your rip fence does not have pre-drilled holes in it, you can safely drill 3 or 4 1/4" holes in it without compensating its integrity. To do this, measure out 3 or 4 holes on your rip fence. If your saw blade is in the middle or near the middle of the rip fence, measure out 4 holes. If the blade is closer to the back of the rip fence, 3 holes is enough. MAKE SURE that you do not put the holes in the area where the blade cuts, keep the holes at least an inch or two from the blade area.
Step 2: Find the perfect piece of wood
Once the holes are drilled, you must find a perfectly straight board. If you have a planer, plane a piece of 2x4 until straight, but not less than 3/4" wide. If you do not have a planer, find a piece of wood that has the slightest bow, this will work also. MAKE SURE your board is the same thickness throughout, this is essential to making the fence true. If you have a planer, use it. The wood should be around the same height and length as the rip fence, but a couple inches difference in length won't hurt.
I used an old piece of decking that was the perfect width, cut it down to size if necessary.