Make sure that the Face Plate Pads are riding on a smooth clean surface of
the drum. If burrs exist around the edges of the bolt holes, place the notches
of the Face Plate over the burrs. This will help as sure precise machining.
Note: On exceptionally small drums and discs, it is sometimes necessary
that only one Face Plate be used, in order for Tool Bit to have sufficient work-
Tapered Hub: Select the proper Centering Cones to fit into hub. On some
hubs the Centering Cones go in only about 1/16 of an inch. Place Centering
Cones for inside of tapered hub onto Arbor, followed by the drum and outside
Tapered Cone. Place additional R-540 Spacers onto Arbor so that when the
Arbor Nut is tightened, the two Centering Cones are drawn tightly against the
1 - 2 2 . Machining Brake Drums:
on Arbor using one
of the methods that
is described in Paragraph 1-21. Place Brake Drum Silencing Band SB-10 around drum
and apply enough tension so that the drum is snugly wrapped. On passenger car drums,
the Brake Drum Silencing Band should be positioned along the edge of the open side of
The Boring Bar (146), Tool Plate (128), and Cross Slide (102), should be adjust-
ed so that the Tool Bit can be placed into the rear of the drum without interference.
These adjustments depend on diameter and depth of the drum. The Boring Bar (146)
can be slid in and out of the Tool Plate (128) by loosening the Cap Screw (150). The
Tool Plate (128) can be rotated by loosening Cap Screw (150), and the Cross Slide (102)
can be moved in or out by rotating Handle (118).
The spindle speed is selected by the following procedure: Switch off Motor (208)
at Switch (201).
Loosen Hand Knob (236) on side of base and give it two full turns counterclock-
1 - 2 6 . Raise Hand Knob (236) to highest position and retighten Hand Knob.
Loosen clasp on side of Guard (239) and swing open Back Guard (241). Move V
Belt (500154) to proper grooves in Step Pulleys (29) and (224).
1 - 2 8 . Loosen Hand Knob (236) and lower to original position.
1 - 2 9 . Retighten Hand Knob (236) firmly using moderate downward pressure.
1-30. Close Back Guard (241) and secure clasp.
Turn machine on at Switch (201).
By rotating Handwheel (243) clockwise and Handle (118) counterclockwise, posi-
tion Tool Bit against drum surface 1/2 inch from outer edge. Engage Shifter Lever
Assembly (71) to the rough cut position in order to remove the outer ridge. If outer
ridge is abnormally high, two or more passes may be necessary.
Bring Tool Bit to rear of drum by turning Handwheel (243) clockwise and remove
1 - 3 4 . Set Tool Bit to desired depth of cut and tighten Thumb Screw (100) to lock Cross
Slide (102). Depth of cut is set by rotating Handle (118) counterclockwise. A typical
rough cut is .006 to .010" deep. Each graduation on the Graduated Collar (115) repre-
Place the Shifter Lever Assembly to the Rough Cut position.
When the Tool Bit leaves the drum, move the Shifter Lever Assembly to the
neutral position. If the drum does not clean up, repeat the above procedures.
1 - 3 7 . Note Rough Cut Setting on Graduated Collar (115), loosen Thumb Screw (100)
and rotate Handle (118) clockwise .015".
Rotate Handwheel (243) until Tool Bit reaches back of drum.
Rotate Handle (118) counterclockwise and set Tool Bit .003" deeper than rough