At this point you have completed two critical tasks
Matched the rotor to the hub by taking into account the imperfect nature of the hub and the stacked tolerances from the hub and other components, thereby eliminating a potential pulsation comeback.
Given the braking surface a new, clean, flat finish that is nearly ready to be mated to the friction material.
The finished surface, by virtue of the off-center design of the Pro-cut adapter threaded center hole, does not require non-directional finish sanding. The design allows the cutting tips to travel in an orbital motion. This eliminates the tendency that bench lathes have to cut a record groove, or a continuous pattern into the rotor that can cause brake noise. However, if you prefer to do a light sanding to reduce the surface finish Ra even further, we suggest 150 grit sandpaper and a half arc sanding block such as the 3M pn# 9292.
Lastly, wash and dry your rotors! Use a spray bottle with warm water with a few drops of dish soap and white paper towel!
Do not use shop rags due to safety concerns of entanglement!
Do not use Brake Clean as it does not work as well for removal of cast iron dust.
The smoother and cleaner the surface, the less potential for a "growl" or other unwanted brake noises!
Final Notes:
If for any reason you must remove the rotor after completing the match-machining process with the PFM lathe, be sure to match-mark the rotor to the hub with a crayon so you can replace the rotor in that same position. Failure to do this will result in a complete undoing of the LRO correction you just finished! For this reason it's always preferable to use the PFM last after all other suspension/hub/axle work is compete, and the wheels are ready to go back on the vehicle.
The lug nuts for the wheels must be torqued to manufacturers' specifications and in a star pattern order. DO NOT use an impact gun without the proper TorqStik or a torque wrench. Uneven torque of lug nuts/bolts will cause the rotor to deflect and will actually induce LRO and cause the undoing of the nearly perfect brake job you just performed!
Test drive the vehicle and follow brake pad manufacturer's recommendations for bed in of new friction material.
