AMMCO 4000E Drum and Disc Brake lathe - Manual (Page 10)

Reconditioning Disc
Brake Rotors
Preparation
1. Inspect the rotor carefully 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.
2. Use a micrometer to check the thickness of the
rotor at no less than 3 points around the circumference
about 1” (2.54 mm) in from the outer diameter.
If the rotor thickness varies between readings, it
should be reconditioned. However, if the thickness is
less than the minimum established by the manufac-
turer, or if it will be less after reconditioning, the rotor
should be replaced.
Note: Most often
the DISCARD thick-
ness dimension is
cast or stamped into
the rotor, not the
minimum machine-
to thickness.
Figure 4 – Measure Rotor Thickness
Model 6950 Twin Cutter
The 6950 twin cutter mounts on the cross feed tool
post to resurface both rotor surfaces simultaneously.
Each tool bar is individually adjustable (in thousandths
of an inch or millimeters) to permit precise depth-of-cut
settings.
The tool bars mount on top of the tool bar support,
carbide tips up, and are used to recondition both brake
surfaces of a rotor at the same time.
Figure 5 – 6950 Twin Cutter Controls
Installation
1. Remove the self-aligning nut/washer assembly
retaining the boring bar clamp.
2. Remove the clamp and boring bar.
Note: Older lathes have a tool post pivot screw which
must be loosened before the lower clamp can be
removed.
3. Place the tool bar support over the cross feed tool
post stud and replace self-aligning nut/washer assem-
bly.
4. Align the tool bar support parallel with the arbor
and wrench tighten the nut.
Preparation
1. Inspect the rotor carefully 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.
2. Use a micrometer to check the thickness of the
rotor at no less than 3 points around the circumference
about 1” (2.54 mm) in from the outer diameter.
If the rotor thickness varies between readings, it
should be reconditioned. However, if the thickness is
less than the minimum established by the manufac-
turer, or if it will be less after reconditioning, the rotor
should be replaced.
Note: Most often the DISCARD thickness dimension
is cast or stamped into the rotor, not the minimum
machine-to thickness.
Inch/Millimeter
Micrometer Dials
Adjustment Knobs
8 • AMMCO Drum & Disc Brake Lathes