Sheave/Drive Belt Replacement - Powermatic 3520C Operating Instructions And Parts Manual

Figure 8-9: sheave/belt alignment

8.12 Sheave/drive belt replacement

IMPORTANT: Replacing the spindle sheave or belt
can be a difficult procedure. If you do not feel
confident performing this action, take the headstock
to an authorized Powermatic service center.
1. Disconnect lathe from power source.
2. Loosen lock handle (J, Figure 8-9) and lift up
handle (K) to raise motor.
3. Tighten lock handle (J) to hold motor in raised
position. Slip belt off pulleys.
4. Loosen two set screws on handwheel (M,
Figure 8-9) with a hex key, and pull handwheel
off headstock spindle.
5. Loosen and remove bearing lock nut and
tabbed lock washer (see O/N, Figure 8-12).
6. Loosen two set screws on sensor collar (R,
Figure 8-10).
7. Remove plate (S, Figure 8-10) and spindle lock
switch (T, Figure 8-10). Remove inner plate (U,
Figure 8-10) and insert hex wrench through
hole to loosen set screw in spindle lock collar
(Figure 8-11).
8. Slide spindle to the right a short way out of
headstock, just enough to remove sheave or
belt. NOTE: You may have to tap end of spindle
with a wood block to move it. (Never use a steel
face hammer directly against spindle.)
9. If replacing spindle sheave, loosen two set
screws (L, Figure 8-9), and slide sheave off
spindle. Install new spindle sheave, loosely
securing the two set screws. Make sure the
sheave is oriented properly.
Figure 8-10: sensor and spindle lock collars
Figure 8-11: loosen spindle lock collar
10. Slide spindle back into place. Position spindle
lock collar and sensor collar and tighten set
screws.
IMPORTANT: The sensor collar must be
positioned correctly for digital readout to
function.
11. Install tabbed lock washer, and bearing lock nut
(N/O, Figure 8-12). Check for any spindle play
at this point (see sect. 8.13).
12. Reinstall handwheel and tighten set screws (M,
Figure 8-9).
13. Reinstall plates and spindle lock switch (Figure
8-10).
14. Align new sheave (see sect. 8.11) then tighten
two set screws (L, Figure 8-9) securely on
sheave.
15. Loosen lock handle (J) and allow motor to
lower. Do not over-tension; a very light pressure
on tension handle (K) is adequate to prevent
belt slippage.
16. Retighten lock handle (J).
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