PHQ250JHMAVL Jackleg MK 1 Parts and Repair Manual PDF

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72. To replace the chuck bushing (C1418A)
invert the chuck under the piston of a hydraulic
press and insert the chuck bushing and tool
T221 for collared insert and T555 for collarless
insert in the open end. Align the chuck, chuck
bushing and the pressing tool and press the
chuck bushing home until fully sealed.
The interference fit between the chuck bushing and the chuck is nominally two thousanths of and
inch and requires from six to fifteen tons of force to push into place. The bushing hits bottom
with an audible “bang” when properly pushed into place in a hydraulic press.
Rifle Nut Removal
73. Inspect the (flutes) splines of the rifle nut (C1508) and replace when
the splines are worn down past 50% of original thickness. Rule of thumb
says that the rifle nut should be replaced whenever the mechanic knows
the drill will be used in a remote, inaccessible or difficult to get to work
place to prevent the premature return of the drill to the repair shop.
C1508 RIFLE NUT NEW C1508 RIFLE NUT 50% WORN C1508 RIFLE NUT 100% WORN
74. The mechanic can make a tool to remove a worn rifle nut (C1508)
from a good piston (B2334) without damaging the piston by welding a
steel handle across the bottom end of a used rifle bar to form a wrench.
A good tool to hold the piston can be made by brazing a used (but fairly
good) chuck nut (C1512) into a used chuck (B1178) and welding the
chuck to the side of the work bench at working height in a convenient
location. Insert the splines on the stem of the good piston into the spines
of the chuck nut. Insert the wrench tool made from a used rifle bar into
the rifle nut and unscrew the rifle nut from the piston head. Note: the rifle
nut is left hand threaded so unscrew in a “clock wise” direction.
Version 200711