I was assuming (only) a pair of surfaces that were parallel with one another, although one can still use soft jaws, even if they are not. The first side would be chucked (with the soft jaws) such that the rotor was not to full depth, which would then allow for machining the first face, from which one would set up to machine the second face. A project such as you mentioned would be accommodated by having deep jaws, relieved, so the rotor would bear only at the outer edge, which would then establish parallelism.dgoddard wrote: Given the need to access both sides of the rotor with the cutting bit the recess places the one side closer to the head stock and the recessed center might interfere interfere with the chuck.
I'm not suggesting that a guy should make this kind of setup. I'm just suggesting that if one is determined, there's a way out that will lead to success. A wise person hauls the rotors to an automotive machine shop and has them faced. The charge is usually reasonable (has been for me in the past).
Not sure where you'd use soft parallels, especially if they are not exactly the same thickness, as any irregularities in the thickness of the rotor will result in less than desirable brakes. Same can be true if one's rotab doesn't happen to be dead parallel with the base, as you'll introduce error that creates lumpy brakes.However I do have a rotary table and mill so that option is likely still available though I might have to make soft parallels for that setup.
The rotary motion is recommended as a means of avoiding alteration of parallelism. If you apply powered devices and don't spin the rotor, good chance you'll create minor deviations. However, if you apply the tool to a spinning rotor, that most likely won't be true. In fact, it can prove to be a pretty good way to accomplish the task. Brings back a memory of being on a 42" DSG lathe, having to create a large internal spherical radius on a large piece of steel. While I don't recall details, I'd suggest the radius was around 18", cut about six inches deep. The radius was roughed by machining, then blended using a 9" disk grinder (using a flex disk, not a wheel), applied as the piece was spinning. Turned out very nicely.All of which may be moot because the Chilton's manual suggests that resurfacing is very possibly unnecessary but does stress breaking the glaze by applying emery cloth with a rotary motion to the braking surface implying that it is an aid to breaking in the new pads. That causes me to wonder if I might not brake the glaze more easily if I were to simply use a 2" Scotch Brite disk or some emery disks and my pneumatic die grinder to save time.
Harold
