essexmetal
March 7th, 2016, 00:43
Let me start by saying, there is nothing like new. But even at the wholesale pricing I get I was not going to drop that much on new rotors for the RS6. Pull off a day at the track or a week on the street and new rotors are now used anyway. In a previous discussion I noted that surface grinding a rotor verses turning it allows you to go through the crust and hard spots and get cleanup with a minimal material removal. My front rotors were deeply grooved and questionable to whether they would go under thickness spec before clean up. They fronts cleaned up with .6 mm over min thickness. The rears 1.0mm over. The rears looked pretty good but were a bit warped. Before you toss yours think about having an engine machine shop run them on a flywheel grinder. You get a perfect unidirectional pattern which aides in pad bedding and just enough clean up to help keep the rotor in spec. Not possible to get the same results with turning.
These rotors were run on a flywheel grinder. I did not take a pic, it is a nasty, dirty process and I hide the machine in an corner of the dirty room where it does not pollute the rest of the shop. They are then mounted on a lathe to chamfer the edges. While chucked up a very, very light pass is taken on the hat mounting face and wheel face. This pass is an absolute minimum cut. Dust coming off not chips. This guarantees a perfectly true running rotor. Then into a drill press for small countersinks of the cross holes. I also run a drill into the cross holes to clean them out, no material removal. Finally into a knife edge balancer for an audit and some balance touch up. Very little was needed, and the material that was removed, was removed from the existing areas where factory balancing was done.
This is obviously easy when you are equipped to perform these processes but I would think most live near a shop that can do the work. Anyone who can do a flywheel can do a rotor. Total time for all processes was 2.25 hours. Even at $100 an hour shop rate that is less than one new rotor. Something to think about.
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These rotors were run on a flywheel grinder. I did not take a pic, it is a nasty, dirty process and I hide the machine in an corner of the dirty room where it does not pollute the rest of the shop. They are then mounted on a lathe to chamfer the edges. While chucked up a very, very light pass is taken on the hat mounting face and wheel face. This pass is an absolute minimum cut. Dust coming off not chips. This guarantees a perfectly true running rotor. Then into a drill press for small countersinks of the cross holes. I also run a drill into the cross holes to clean them out, no material removal. Finally into a knife edge balancer for an audit and some balance touch up. Very little was needed, and the material that was removed, was removed from the existing areas where factory balancing was done.
This is obviously easy when you are equipped to perform these processes but I would think most live near a shop that can do the work. Anyone who can do a flywheel can do a rotor. Total time for all processes was 2.25 hours. Even at $100 an hour shop rate that is less than one new rotor. Something to think about.
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