AMMCO 7000 Disc Rotor Lathe - Manual (Page 12)

Reconditioning Disc Brake Rotors
Each brake disc should be carefully inspected for SCORING,
RUST RIDGES (at the inner and outer circumference of the
rotor), and HARD SPOTS. Any excessive wear or deformity
should be noted and, if not within acceptable limits, the rotor
should be replaced. Use a micrometer to check the thickness of
the rotor at no less than three points around the circumference
about 1" (25.4 mm) in from the outer diameter, Fig. B 7. If the
rotor thickness varies between readings, it should be machined;
however, if the thickness is less than the minimum established
by the car manufacturer (or if it will be less after reconditioning),
the rotor should be replaced.
Note: Most often the discard thickness dimension is cast into
the rotor, not the minimum machine to thickness.
Mount the twin cutter on the cross feed with the stud bolt
extending through the cast slot. In some applications the stud
bolt may have to be positioned in one of the alternate stud
mounting holes, Fig. B 8. To prevent contamination of the gear
box position set screw in unused hole. To secure the twin cut-
ter use the nut and washer assembly and tighten firmly.
Rotor Mounting
Fig. B20, TYPICAL ROTOR MOUNTING CONFIGURATIONS is
a model example of many of the mounting configurations nec-
essary to meet the requirements of brake rotor machining.
Inspect the rotor hub for loose or damaged bearing races and
replace parts as necessary. Hubbed rotors are mounted on the
taper adapters that fit into the bearing races. Hubless rotors use
a cone in the center hole and a hubless adapter on each side of
the rotor. Spacers are used to fill out the arbor shaft so that the
arbor nut can be tightened. The adapters, cones, and spacers
supplied with your lathe will allow you to recondition the major-
ity of rotors on today’s vehicles. Optional adapters, cones, and
spacers are available to meet special needs.
Note: Adapters may also be used as spacers to fill out the
arbor if care is taken to prevent damage to their machined sur-
faces. The patented self-aligning spacer prevents diagonal thrust
on the adapters. The self-aligning spacer should always be used
adjacent to the arbor nut.
Brake Lathes
6 • AMMCO 7000 Brake Lathes
Figure B7
Figure B8