MAHLE RTI BRC550 - Manual (Page 17)

Page 15
VI. Cutting Drums
A. Mounting. Mounting a brake drum on the arbor is similar to mounting a brake rotor/disc. See
Figures 8 and 9. In order to have clearance for the drum, you will first need to loosen the (2) square
locking screws holding the rotor cutting tool holder assembly and either: 1) Remove the entire rotor
cutting tool holder assembly from the tool slide, or 2) Rotate the assembly 180 degrees so the tool
holders point away from the arbor and re-tighten the locking screws. Rotating the assembly is
recommended and will give enough clearance for all but larger drums.
B. Install and Position Cutting Tool. Move the tool slide inward manually. Install the drum cutting
tool bar in the slot of the tool slide. Position the bar so that the cutting tip extends toward the drum,
past the edge of the tool slide as necessary to cut the entire drum surface. Then lock the bar in
place with the square locking screws. Normal operation is with the large drum cutting tool toward
the drum. (See Figure 10) For larger drums, it may be necessary to reverse the position of the
cutting tool bar, using one of the rotor cutting tool holders installed on the bar as shown.
C. Vibration Dampener. Install the vibration dampening belt to minimize noise and vibration.
D. Setting Depth of Cut and Speed. Using the hand wheel on the right side of the lathe, move the
cutting tip inside the drum and position the cutting tip 1/4" (6 mm) inside the lip of the drum.
Manually remove the ridge and move the tool manually inward using the same general procedure
as with rotors/discs so as to establish the initial cutting position. The manual “feed” movement of
the cutting tool is with the side handwheel that moves the tool slide side to side. Depth of cut of the
cutting tool is set manually using the handwheel in the front of the lathe that moves the tool slide
in and out. The graduated hub on this handwheel will indicate the precision movement to set the
depth of cut. Once the depth of cut is set as desired, set the feed at “2-2.5=medium”. Set the feed
selector switch to “left to right” and push the black knob in the center of the side handwheel inward
so that the tool slide moves to the right automatically. The same general procedures as to checking
for discard thickness of a rotor/disc apply to the discard diameter of a drum. The same general
issues of “one-pass” and “multi-pass” cutting also apply. The major difference of operation is simply
that the auto feed for drums is from left to right instead of in to out and the depth of cut is set using
the outer handwheel.
VII. Locking the Tool Slide
In order to ensure the very best precision, the BRC500/550 has the provision to allow the operator
to lock the tool slide during cutting. (See Figure 11) This is more important for cutting rotors where
near zero run out is desired. Therefore the locking provision for the side to side movement of the
tool slide during rotor/disc machining is accomplished by tightening the black plastic knob. To lock
the in/out movement of the tool slide when cutting drums, an Allen type wrench is required. The
tool slide locks push a small aluminum pad against the tool slide guide. Do not over tighten the lock
or the pad may be damaged. Be sure the tool slide lock is only engaged during the final cut and
is disengaged when the cut is complete!