Hitachi WH 12DH Technical Data And Service Manual page 32

(3) Reassembly of the Mechanical Parts
(a) Put the Washer (S) [13] <11> onto the shaft of the Spindle [15] <13> and mount the Hammer [10] <7>
containing the twenty-five Steel Balls D3.5 [7] <8>, Washer (J) [11] <9> and the Spring [12] <10> to the
Spindle [15] <13>.
(b) Align the top of the cam groove on the Spindle [15] <13> with the steel ball guide groove on the Hammer
[10] <7> as illustrated in Fig. 11. Press down either of the raised faces of the Hammer [10] <7> with a
hand press to compress the Spring [12] <10> until the end surface of the Hammer contacts the flange of
the Spindle [15] <13>.
(c) Insert the two Steel Balls D5.556 [9] <6> into the steel ball guide groove. Check that the Steel Balls are
properly inserted in the cam groove. Then release the hand press.
(d) Mount the hammer assembly onto the J-297 base for washer (S). With a hand press, push down the top of
the Spindle [15] <13> to compress the Spring [12] <10>. On this condition, mount the Stopper [14] <12>
onto the spindle shaft and then release the hand press.
(e) Mount the Ring Gear [18] <16>, the Ball Bearing [20] <18>, the Inner Cover [21] <19> and the Damper
[22] <20> to the above reassembly. Furthermore, mount the other mechanical parts and Anvil (B) [8] or
Anvil (K) Ass'y <4>, then the Hammer Case [6] <2>. When mounting Anvil (B) [8], use the J-296 anvil cap
(Fig. 13).
(Note) The oil seal may be turned inside out if the anvil cap is not used.
(4) Mounting the assembly from the Hammer Case [6] <2> to Inner Cover [21] <19> to the housing assembly
Push the assembly from the Hammer Case [6] <2> to the Inner Cover [21] <19> into the housing assembly by
turning them clockwise and counterclockwise. Check that the Anvil can be easily turned. (If it cannot be
turned, check for correct mesh of the gears.) Secure the above assembly with the four Tapping Screws D4 x
30 [5] <1>.
(5) Reassembly of the Guide Sleeve [4] (for WH 12DH only)
Insert the Steel Ball D3.5 [7] into the hole of the Anvil (B) [8]. Mount the Guide Sleeve [4], the Guide Spring
[3] and Washer (D) [2] in sequence. Mount the Retaining Ring [1] into the groove of Anvil (B) using the J-295
jigs (A) and (B) for retaining ring as illustrated in Fig. 14.
Fig. 13
J-296 anvil cap
Anvil (B) [8]
--- 29 ---
Retaining
Ring [1]
Washer (D) [2]
Fig. 14
Push down.
J-295 jig (B) for retaining ring
J-295 jig (A) for retaining ring