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2. Mounting the mechanical parts
(1) Mount Washer (S) [16] to the Spindle [18]. Put the twenty-eight Steel Balls D3.175 [13], Washer (J)
[14], and Hammer Spring [15] in the Hammer [12], and mount it to the Spindle [18].
(2) Align the highest point of the cam groove in the Spindle [18] with the steel ball insertion groove in the
Hammer [12]. Push down the tabs on the Hammer [12] with a hand press or similar tool to compress
the Hammer Spring [15] until it contacts the Spindle [18] and hold it there.
(3) Insert the two Steel Balls D5.556 [11] into the steel ball insertion groove. Check that the two Steel Balls
D5.556 [11] are in the groove, and then loosen the hand press.
(4) Set the hammer assembly onto the J-297 base for washer (S) (special-purpose tool, Code No.
317063), press the hand press down on the edge of the Spindle [18] to compress the Hammer Spring
[15], and then mount Stopper (A) [17] to the Spindle [18]. Loosen the hand press to complete the
procedure.
(5) Mount the Idle Gear Set (2 pcs.) [19] and two Needle Rollers (A) [20] to the Spindle [18] and insert
Washer (E) [21] to assemble the hammer assembly.
(6) Press-fit the Ball Bearing 6901VV [22] into the Inner Cover [26] and fit two Dampers (A) [25] into the
Inner Cover [26]. Then fit the O-ring [24] into Ring Gear (A) [23], and fit the retaining rib of Ring Gear
(A) [23] into the concave portion of Damper (A) [25].
(7) Check the hammer assembly (whether Washer (E) [21] is inserted into the Spindle [18]) for proper
engagement of the Idle Gear Set [19] with Ring Gear (A) [23], and mount it to the Inner Cover [26].
(8) Insert the Anvil [10] into the tip of the Spindle [18] of the hammer assembly, and then cover it with the
Hammer Case [7].
NOTE: At that time, make sure that the ribs of the Inner Cover [26] are positioned at 90° relative
to the retaining tabs of the Hammer Case [7].
(9) Press-fit the Wiring Ass’y [29] all the way into the Inner Cover [26]. Make sure that the Wiring Ass’y
[29] turns smoothly. If the Wiring Ass’y [29] does not turn smoothly, its gears could be improperly
engaged. In such a case, mount the Wiring Ass’y [29] properly.
90°
Retaining tabs of the Hammer Case [7]
• Mounting the mechanical parts
Ribs of the Inner Cover [26]
