I created these brake rotors for my 1/12 GT500 out of 1 1/4" washers at local home store (Menards)
Put a bolt thru the washer, put a nut on it, and put it in the drill. While i spun it with the drill I ran a sharp screwdriver
over the surface to create the machined look of a rotor. The caliper was made out of nylon 1 1/4" washers that were stacked
and glued and then cut out and machined with a Dremel tool. Because there are many different sizes of washers out there you
could use this tip for virtually any size model. Cost was about $3.00 or so.