CALIBRATING SPINDLE SPEEDS 1. Turn on the motor and set the pointer (B) Fig.  15, to the lowest speed.  (Either 350 or 230 rpm.) 2. Loosen  the  hex  lock  nut  and  then  adjust  screw  (C) Fig.    15,  to  provide  a  positive  stop  for  the  pointer  at  the lowest   speed.      The   best   way   is   to   turn   the   screw clockwise  (up)  until  the  pointer  cannot  be  turned  to  the lowest speed, and then turn the screw counter clockwise (down)   a   little   at   a   time   until   the   pointer   is   stopped positively, just as it comes to the lowest speed.  Tighten the hex lock nut. 3. Increase  the   speed   until   the   pointer   is   set   at   the highest speed.  (4250 or 2830 rpm.) Loosen the hex lock nut  and  adjust  the  screw  (D)  Fig.    15,  until  the  spindle pulley  is  stopped  from  opening  any  additional  amount, just   as   the   pointer   shows   4250   (or   2830)   rpm.      The pointer  will  go  on  past  the  mark,  but  there  will  be  no actual    change    in    spindle    speeds    or    pulley    opening beyond  the  movement  allowed  by  stop  screw  (D),  Fig. 15.  Tighten the hex nut. 4. With  the  pointer  at  the  highest  speed,  the  outside circumference   of   the   belt   should   now   protrude   about 1/32"   beyond   the   outside   circumference   of   the   motor pulley.    If  the  belt  does  not  protrude  enough,  move  the motor  plate  in  toward  the  head,  until  the  clearance  is  a little   bit   less   than   7/8",   as   mentioned   in   paragraph  4 under  INSTALLATING  MOTOR  AND  BELT.    If  the  belt protrudes  too  much,  the  clearance  between  head  and motor  plate  should  be  increased.    (Be  sure  to  keep  the motor shaft parallel with the spindle of the drill press.) 5. When   greater   accuracy   is   required,   a   tachometer should   be   used.      Before   following   steps   1   through   4 above, proceed as follows. 6. Turn  on  the  motor  and  turn  the  pilot  wheel  (A)  Fig. 15   counter   clockwise,   until   the   tachometer   shows   a speed  of  350  or  230  rpm,  depending  on  whether  the motor    runs    at    1725    or    1140    rpm.        Then,    without changing   speeds,   adjust   the   pilot   wheel   so   that   the pointer shows exactly 350 (or 230) rpm.  This adjustment is made as follows. 7. Unscrew and remove the two spokes (A) of the pilot wheel   shown   in   Fig.      15.      Then   loosen   the   two   set screws found in the holes thus exposed in the hub of the pilot   wheel   and   rotate   the   hub   so   that   pointer   (B) indicates  the  lowest  speed  on  the  dial.    Tighten  the  two set screws and replace the two spokes. 8. Follow  steps  2,  3  and  4.    After  completing  step  4, check  the  top  speed  with  the  tachometer.    If  necessary, move the motor plate in to increase the spindle speed as shown on the tachometer or out to decrease it. 9. If the motor plate is moved in or out in step 8, above, the  lowest  speed  will  be  affected,  percentage  wise,  the same  as  the  highest  speed.    But  the  change  in  fpm  will be  very  slight  at  the  lowest  speed  setting.    No  further adjustment of the lowest speed is recommended. Fig.  15 SPECIAL NOTE The   tension   on   the   belt   is   governed   by   the   specially engineered spring of the motor pulley.  No adjustment is possible  to  change  the  belt  tension.    If  the  speeds  are properly calibrated and the pulleys properly lined up, the correct   belt   tension   will   be   maintained   automatically regardless  of  normal  wear  on  the  belt  and  the  pulleys. This    feature    provides    long    belt    life    by    avoiding    the slippage which is experienced due to insufficient tension on   belt   drives   which   are   not   fully   engineered.      The automatic   belt   tensioning   feature   also   provides   longer bearing   life   in   both   drill   press   and   motor,   because excessive belt tension is avoided. After   a   long   period   of   time   pulley   and   belt   wear   and stretching  of  the  belt  may  cause  a  slight  change  in  the speed  of  the  drill  press.    To  compensate  for  this  change in  speed,  use  a  tachometer  and  move  the  motor  toward or away from the spindle pulley until the correct speed is obtained. 9