Hitachi DH38MS Manual

PRODUCT NAME
Hitachi Rotary Hammer
Model DH 38MS
The new Model DH 38MS is capable of drilling holes of up to 38 mm in diameter into concrete and is compatible
with SDS max shank tools.
LIST No.
DH 38MS: H402
May 2009
xDrilling holes in concrete and drilling anchor holes.
xDemolishing and chiseling concrete. Edging, gravel road digging, compacting and tamping, grooving, cutting,
stripping and roughing, etc.
MARKETING OBJECTIVE
APPLICATIONS
SELLING POINTS
International Sales Division
D
<New features>
Fastest drilling speed and best chiseling
performance in its class
Functional and robust design
<Same features as the conventional models>
Easy-to-operate with a double-molded side handle
Variable lock mechanism for easy working-angle
adjustment of chisels, etc.
Needle-pin type of slip clutch
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.

REMARKS:
For more information about HANDLING INSTRUCTIONS, visit our website at:
http://www.hitachi-koki.com/manual_view_export/
This TECHNICAL DATA AND SERVICE MANUAL utilizes a symbol to denote the company name and
model name of our competitor. The symbol utilized herein is as follows:
Competitors
Symbol utilized Company name Model name
B BOSCH GBH5-38D

CONTENTS
Page
SELLING POINTS ------------------------------------------------------------------------------------------------------------- 1
SPECIFICATIONS ------------------------------------------------------------------------------------------------------------- 3
1. Specifications----------------------------------------------------------------------------------------------------- 3
2. Optional Accessories ------------------------------------------------------------------------------------------- 4
COMPARISON WITH SIMILAR PRODUCTS--------------------------------------------------------------------------- 8
1. Comparison of Specifications------------------------------------------------------------------------------------------------------- 8
PRECAUTIONS ON SALES PROMOTION ----------------------------------------------------------------------------- 9
1. Safety Instructions ---------------------------------------------------------------------------------------------- 9
REFERENCE MATERIALS-------------------------------------------------------------------------------------------------10
REPAIR GUIDE---------------------------------------------------------------------------------------------------------------- 11
1. Precautions on Disassembly and Reassembly --------------------------------------------------------- 11
STANDARD REPAIR TIME (UNIT) SCHEDULES--------------------------------------------------------------------17
Assembly Diagram for DH 38MS

-1-
Comparison of chiseling performance
Chiseling amount (kg/30 min.)
0
50
100
150
200
250
300
16 18 20 22 24 26 28 30 32 34 36 38
Drill Bit Dia. (mm)
Drilling Speed (mm/min)
HITACHI DH38MS
B
HITACHI DH40MR
62
44
46
0 20406080100
Fastest drilling speed and best chiseling performance in its class*
We conducted digital engineering to determine the optimal impact specifications. As a result, the Models
DH 38MS offers the fastest drilling speed and best chiseling performance in its class.
*Based on our own research
Comparison of drilling speed
Chiseling performance varies considerably depending on the work conditions.
Use the factory test results for comparison purposes only.
HITACHI
DH 38MS
HITACHI
DH 40MR
B
<Test conditions>
Direction: Downward drilling
Pushing force: 98 N (10 kgf)
Test material: Concrete panel with a compression strength of 2,352 N/cm2(240 kgf/cm2)
SELLING POINTS

-2-
Refer to the Technical Data and Service Manual of the current Model DH 40MR for the following.
Easy-to-operate and double-molded side handle
The base material of the side handle is plastic resin. The plastic resin base is integrally molded with soft
resin to realize a double-layer structure. As a result, the grip of the soft side handle affords easier operation.
Change lever for switching between “Rotation + Hammering,”
“Neutral” and “Hammering only”
The Models DH 38MS provides three functions; the
“rotation + hammering” function (for drilling), “neutral”
function (for positioning the tool tip) and “hammering
only” function (for chiseling and chipping).
These function modes can be easily switched by
using the change lever. The tool angle can be easily
changed in 12 steps by turning the grip with the
change lever positioned at “Neutral.”
Needle-pin type of slip clutch
The Model DH 38MS is equipped with a needle-pin type of slip clutch for higher slip torque accuracy and
enhanced safety (same as the Model DH 40MR).
DH 40MR / List No. E467

-3-
1. Specifications
Model - DH 38MS
Drill bit (max. dia.): 38 (1-31/64”)
Capacity mm Core bit (max. dia.): 105 (4-9/64”)
Voltage V 110 120 220 230 240
Current A 9.1 8.4 4.6 4.4 4.2
Power input W 950
Enclosure -
Materials : Aluminum alloy die casting
(Cylinder case, crank case, gear cover)
Nylonresin
(Handle, handle cover, tail cover, crank cover)
Polycarbonateresin
(Housing)
Paint : Green, black, silver metallic green
Switch - Trigger switch
Type of handles - D-shaped handle and side handle
No load rotation rate min-1 620
Full load impact rate min-1 2,800
Packaging - Plastic case
Product*6.4 (14.1)
Weight Packed kg (lbs.) 9.5 (20.9)
Standard accessories -
· Plastic case ------------------------------------------------------ 1
· Side handle ------------------------------------------------------ 1
*:Excluding cord and side handle
SPECIFICATIONS

-4-
2. Optional Accessories
(1) Drilling work for through-hole drilling (rotation + impact)
D mm L mm Code No. D mm L mm Code No.
16 (5/8”) 340 (13-3/8”) 313448 16 (5/8”) 540 (21-1/4”) 313456
19 (3/4”) 340 (13-3/8”) 313449 19 (3/4”) 540 (21-1/4”) 313457
22 (7/8”) 320 (12-5/8”) 313450 22 (7/8”) 520 (20-15/32”) 313458
25 (1”) 320 (12-5/8”) 313451 25 (1”) 520 (20-15/32”) 313459
28 (1-1/8”) 370 (14-9/16”) 313452 28 (1-1/8”) 570 (22-7/16”) 313460
32 (1-1/4”) 370 (14-9/16”) 313453 32 (1-1/4”) 570 (22-7/16”) 313461
38 (1-1/2”) 370 (14-9/16”) 313454 38 (1-1/2”) 570 (22-7/16”) 313462
(2) Drilling work for anchor holes (rotation + hammering)
Drill bit (taper shank)
(1) Drill bit (taper shank) (2) Taper shank adapter (3) Cotter
D mm L mm Code No. Taper dimension Code No. Code No.
11.0 (7/16”) 100 (4”) 944460
12.3 (15/32”) 110 (4-5/16”) 944461
14.3 (9/16”) 110 (4-5/16”) 944462 Morse taper No. 1 313464 944477
14.5 (9/16”) 110 (4-5/16”) 944500
17.5 (11/16”) 120 (4-3/4”) 944463
SDS-plus shank bit adapter
Code No.
313465
Drill bit (SDS max shank)
D
L
(1) Drill bit (taper shank) (2) Taper shank adapter
(SDSmaxshank)
(3) Cotter
D
L
+
+
Drill bit (SDS-plus shank) SDS-plus shank
bit adapter
(SDS max shank)

-5-
(3) Boring work for large-diameter holes (rotation + hammering)
(2) Core bit (1) Center pin (3) Core bit shank (SDS max)
D mm Code No. Guide plate l mm Code No. L mm Code No.
25 (1”) 955994 -
29 (1-1/8”) 955995 ---
32 (1-1/4”) 955996
35 (1-3/8”) 955998
300 (11-13/16”) 313466
38 (1-1/2”) 956000
147 (5-25/32”) 956009
45 (1-3/4”) 955154
54 (2-1/8”) 955155
64 (2-1/2”) 956002
79 (3-1/8”) 955157
94 (3-11/16”) 956004
105 (4-1/8”) 955159
133 (5-1/4”) 955165 300 (11-13/16”) 313467
(4) Hole drilling
13-mm drill chuck (13VLD-D) with chuck wrench Chuck adapter
Code No. Code No.
321813 313468
(5) Chemical anchor holes drilling work (rotation + hammering)
Socket square size mm Code No.
12.7 (1/2”) 313469
19.0 (3/4”) 313470
lL
Chuck adapter
(SDS max shank)
(1) Center pin (2) Core bit
+++
(Guide plate)
+
+
D
13mm drill chuck
(13VLD-D)
(3) Core bit shank
(SDS max shank)
Chuck wrench
(Socket) Chemical anchor adapter
(SDS max shank)

-6-
(6) Demolishing work (hammering)
Bull point (SDS max shank)
L mm Code No.
280 (11”) 313471
450 (15-3/4”) 313472
(7) Groove digging and edging (hammering)
Cold chisel (SDS max shank)
L mm Code No.
280 (11”) 313473
450 (15-3/4”) 313474
(8) Cutting and stripping (cutting asphalt etc.) (hammering)
Cutter (SDS max shank)
L mm Width mm Code No.
400 (15-3/4”) 50 (2”) 313475
(9) Scooping work (hammering)
Scoop (SDS max shank)
L mm Code No.
400 (15-3/4”) 313476
(10) Surface roughing work (hammering)
Code No. L mm Code No.
313477 220 (8-21/32”) 313479
L
L
L
L
L
+
Bushing tool Shank (SDS max shank)

-7-
(11) Tamping work (hammering)
L mm Code No. l mm Code No.
150 (5-29/32”) 313478 220 (8-21/32”) 313479
(12) Syringe (for chip removal)
Syringe Code No.
Bellows 318085
Blow-out bulb 320859
(13) Grease
Code No. Code No.
980927 981840
NOTE:
The code numbers listed above are subject to change without notice.
Please refer to periodic Technical News Bulletins for updates
l
L
500
g(
1.1 lbs.
)
can 30 g (1 oz) tube
+
Rammer Shank (SDS max shank)
Bellows Blow-out bulb

-8-
1. Comparison of Specifications
(Superior specifications: )
Maker HITACHI
Model name DH 38MS DH 40MR B
Drill bit dia. mm 38
(1-1/2”)
40
(1-9/16”)
38
(1-1/2”)
Capacity
Core bit dia. mm 105
(4-1/8”)
105
(4-1/8”)
90
(3-17/32”)
Power input W 950 950 1,050
Full-load rotation rate min-1 510 240 - 480 340
Full-load impact rate min-1 2,800 1,320 – 2,650 3,000
Full-load vibration level
(Tri-axial, measured) m/s216.1 18.8 16.1
No-load noise level
(measured) dB 85.0 81.2 85.7
Full-load noise level
(measured) dB 92.7 92.3 93.3
Length 433
(17-1/64”)
435
(17-1/8”)
430
(16-15/16”)
Height 247
(9-3/4”)
255
(10-3/64”)
253
(9-31/32”)
Tool size
Width
mm
103
(4-1/32”)
104
(4-7/64”)
102
(4-1/16”)
Weight*kg (lbs.) 6.4 (14.1) 6.5 (14.3) 5.8 (12.8)
*: Weight does not include the cord and side handle
COMPARISON WITH SIMILAR PRODUCTS

-9-
1. Safety Instructions
In the interest of promoting the safest and most efficient use of the Model DH 38MS Rotary Hammer by all
of our customers, it is very important that when conducting a sale that the salesperson carefully ensure that
the buyer seriously recognizes the importance of Handling Instructions, and fully understands the
precautions listed on the Caution Plate and Nameplate attached to each tool.
A. Handling instructions
Although every effort is made in each step of design, manufacture, and inspection to provide protection
against safety hazards, the dangers inherent in using any electric tool cannot be completely eliminated.
Accordingly, the Handling Instructions list general precautions and suggestions on the use of electric power
tools, and specific precautions and suggestions on the use of rotary hammers to enhance the safe, efficient
use of the tool by the customer. Salespersons must be thoroughly familiar with the contents of the Handling
Instructions in order to offer appropriate guidance to customers during sales promotion activities.
B. Caution plate
Each Model DH 38MS unit is provided with a Caution Plate (shown below) that lists basic safety
precautions on its use. Carefully ensure that customers fully understand and follow these precautions
before using the tool.
[For Australia and New Zealand]
[For the USA and Canada]
[For China]
PRECAUTIONS ON SALES PROMOTION

-10-
C. Grease replacement procedures
The hammering section and gear change section use different types of grease. There is no need to
replenish the grease unless disassembling the tool for repair or in case grease is leaking due to a damaged
seal.
Special grease is used for the hammering section. After disassembling the hammering section (inside the
cylinder case and crankcase), carefully wipe the old grease off the parts and fill the cylinder case and
crankcase (on the connecting rod side) with 50 g of grease. Be careful not to overfill the grease as an
excessive amount of grease can cause hammering failure.
The gear change section (inside the gear cover) uses Hitachi Motor Grease No. 29. The proper amount of
grease is 30 g. Never use this special grease for the hammering section in the gear change section.
Otherwise, the special grease will leak into the motor section and subsequently cause trouble. Periodically
change the grease in the slip clutch. Fully fill the slip clutch with Hitachi Motor Grease No. 29.
Refer to the Technical Data and Service Manual for the model indicated below.
1. Torque transmission
2. Striking operation
3. Mechanism to prevent idle hammering
4. Slip clutch mechanism
5. Tool holder
6. Sealing and dust-proof structure
7. Switching between “Rotation + Hammering”, “Neutral” and “Hammering only”
REFERENCE MATERIALS
DH 40MR / List No. E467

-11-
Retainer Sleeve [12]
Stopper Ring [3]
Retainer Spring [5]
D8 X 20 Needle Roller [13]
Needle Holder [4] Spring Holder (A) [6]
Be sure to disconnect the power cord plug from the wall outlet before conducting repair. Otherwise, the
motor may suddenly run, posing a very dangerous situation.
1. Precautions on Disassembly and Reassembly
The [Bold] numbers in the descriptions below correspond to item numbers in the Parts List and exploded
view assembly diagram for the Model DH 38MS.
1. Disassembly of the tool retainer
While pulling the Grip [2] in the arrow direction, remove the Front Cap [1], which is fitted securely. (Forcibly
pull the Front Cap [1] to remove it.) Then the Grip [2] can be removed from the Retainer Sleeve [12].
Remove the Stopper Ring [3] by using a retainer ring puller. Then the Needle Holder [4], two Needle
Rollers D8 x 20 [13], Retainer Spring [5] and Spring Holder (A) [6] can be removed from the Retainer
Sleeve [12] (Fig. 1).
2. Disassembly of the hammering mechanism
(a) Second Hammer [15] and Striker [27]
Remove the Seal Lock Hex. Socket Hd. Bolt M5 x 16 [67] from the Crank Cover [68]. Remove the Crank
Cover [68] from the Crank Case [70]. Remove the Seal Lock Hex. Socket Hd. Bolt M6 x 20 [64] and Seal
Lock Hex. Socket Hd. Bolt M6 x 45 [65]. Remove the Gear Cover [80] from the Crank Case [70]. Remove
the Slip Clutch Ass'y [49] from the Crank Case [70] beforehand because the Bevel Gear [25] cannot be
removed with the Slip Clutch Ass'y [49] remaining in the Crank Case [70]. Remove the Seal Lock Hex.
Socket Hd. Bolt M4 x 12 [32] and the Change Lever [33]. Remove the Retaining Ring for D20 Hole [35]
securing the Lever Shaft [36] with a retaining ring puller. Remove the Lever Shaft [36] from the Crank Case
[70] beforehand because the Bevel Gear [25] cannot be removed with the Lever Shaft [36] remaining in
the Crank Case [70]. Remove the Seal Lock Hex. Socket Hd. Bolt (W/Flange) M6 x 25 [8]. Then the
Cylinder Case [7], Spring Holder (B) [20], Retainer Sleeve [12] and other parts can be removed from the
main body. Remove the Second Hammer [15] from the Retainer Sleeve [12] together with the Damper
Holder [18], Damper [17] and Damper Washer [16]. Pull out the Cylinder [19] from the main body together
with the Lock Spring [21], Lock Sleeve [22], Clutch Spring [23] and Clutch [24]. Remove the Striker [27] by
tapping the end surface of the Cylinder [19] with a plastic hammer (Fig. 2).
REPAIR GUIDE
Disassembl
y
Fig. 1
Front Cap [1]
Grip [2]

-12-
(b) Piston [30]
To remove the Piston [30], use a retaining ring puller to remove the Retaining Ring for the D10 Shaft [72],
and then remove the Connecting Rod [31] from the Crank Shaft [73].
(c) First Gear [78] and Crank Shaft [73]
Remove the Seal Lock Hex. Socket Hd. Bolt M6 x 45 [65], Seal Lock Hex. Socket Hd. Bolt M6 x 20 [64],
Hex. Socket Hd. Bolt (W/Flange) M5 x 16 [67] and Tapping Screw (W/Flange) D5 x 30 (black) [95].
Remove the Crank Case [70] from the Housing Ass'y [48] and Handle [97]. Remove grease from the
Piston [30] side and First Gear [78] side of the Crank Case [70]. Use a retaining ring puller to remove the
Rataining Ring for D40 Shaft [74] fixing the Ball Bearing 6203DDCMPS2L [75]. At this time, turn the Crank
Shaft [73] to expose the hole of the Retaining Ring for the D40 Shaft [74] prior to removal. Use a hand
press to press the end face of the Crank Shaft [73], and then remove the First Gear [78] and Crank Shaft
[73] from the Crank Case [70] (Fig. 3).
Crank Shaft [73]
Retaining Ring for D40 Hole [74]
Crank Case [70] Crank Case [70]
Crank Shaft [73]
First Gear [78]
Support
Fig. 3
Fig. 2
Retainer Sleeve [12]
Damper Washer [16]
Cylinder Case [7]
Striker [27]
Lock Sleeve [22]
Cylinder [19] Piston [30]
Damper [17]
Second Hammer [15]
Retaining Ring for D10 Shaft [72]
Clutch Spring [23]
Clutch [24]
Retainer Damper Washer [11]
Crank Shaft [73]
Lock Spring [21]
Connecting Rod [31]
Spring Holder (B) [20]
Damper Holder [18]
Retainer Damper [10]

-13-
Oil seal (B) [77]
BB.6203DDCMPS2L [75]
3 x 3 x 8 Key [51]
Retaining Ring for D40 Hole
O-ring [76]
Crank Shaft [73]
First Gear [78] Support
Steel Bar
(d) Slip Clutch
Refer to the Technical Data and Service Manual for the Model DH 40MR (List No. E467) because the slip
clutch mechanism is the same as that of the Model DH 40MR.
Perform reassembly by reversing the order of the disassembly procedure. However, special attention
should be given to the following items.
1. Reassembly of the hammering mechanism
(a) First Gear [78] and Crank Shaft [73]
Press-fit Oil Seal (B) [77] into the Crank
Case [70] and mount the O-ring [76]. Then
press-fit the Ball Bearing 6203DDCMPS2L
[75]. Use a retaining ring puller to mount the
Retaining Ring for the D40 Shaft [74].
Press-fit the Crank Shaft [73] into Ball
Bearing 6203DDCMPS2L [75]. Put the
Feather Key 3 x 3 x 8 [51] into the groove of
the Crank Shaft [73] and then press-fit the
First Gear [78] with a suitable jig, while
holding the flat portion of the Crank Shaft
[73] with a steel bar. Before press-fitting,
make sure that the Feather Key 3 x 3 x 8
[51] fits into the key groove of the First Gear
[78] (Fig. 4).
(b) Piston [30]
Insert the Connecting Rod [31] into the Piston [30] and then insert the Piston Pin [29] into the 8-mm dia.
hole (on the marked side) of the Piston [30]. (Be careful not to protrude the Piston Pin [29] from the outer
diameter of the Piston [30].) Mount the O-ring [28] to the Piston [30] to complete the piston ass'y. Move the
crank pin of the Crank Shaft [73] to the bottom dead center, and then mount the piston ass'y to the Crank
Shaft [73] from the Cylinder Case [7] side of the Crank Case [70]. Use a retaining ring puller to mount the
Retaining Ring for the D10 Shaft [72] (Fig. 5).
Reassembl
y
Fig. 4
Fig. 5
Retaining Ring for D10 Shaft [72] Crank Shaft [73]
Crank Case [70]
Piston Pin [29] Piston[30]
Mark
O-Ring [28]
Piston Ass’y
Connecting Rod [31]

-14-
(c) Cylinder [19] and Retainer Sleeve [12]
Mount the Retainer Damper Washer [11] and Retainer Damper [10] to the Retainer Sleeve [12] in this
order by aligning the rounded portion of the Retainer Damper Washer [11] with the rounded portion of the
Retainer Sleeve [12]. Mount the Second Hammer [15] (with O-ring (C) [14] mounted), Damper Washer
[16], Damper [17] and Damper Holder [18] in this order by aligning the rounded portion of the Damper
Washer [16] with the rounded portion of the Second Hammer [15]. Insert the assembly of the Retainer
Sleeve [12] into the Cylinder Case [7], and then insert Spring Holder (B) [20] into the Cylinder Case [7].
Insert the Striker [27] (with the O-ring [28] mounted) into the Cylinder [19]. Mount the Clutch Spring [23],
Clutch [24], Bevel Gear [25] and Thrust Washer [26] to the Cylinder [19], and then insert this Cylinder [19]
ass'y into the Crank Case [70]. Insert the Lock Sleeve [22] into the Crank Case [70] by aligning the spline
groove at the inner circumference of the Crank Case [70] with the spline of the Lock Sleeve [22]. Put the
Lock Spring [21] on the Lock Sleeve [22]. Finally put the Cylinder Case [7] (with the Retainer Sleeve [12]
mounted) and the Crank Case [70] (with the Cylinder [19] mounted) together by meshing the claw of the
Retainer Sleeve [12] with the groove of the Cylinder [19] (Fig. 6).
(d) Slip Clutch
Refer to the Technical Data and Service Manual for the Model DH 40MR (List No. E467) because the slip
clutch mechanism is the same as that of the Model DH 40MR.
Crank Case [70]
Cylinder Case [7]
Damper Holder [18]
Spring Holder (B) [20]
Damper Washer [16]
Damper [17]
Second Hammer [15]
Retainer Damper Washer [11]
Retainer Sleeve [12]
Retainer Damper [10]
Thrust Washer [26]
Lock Spring [21]
Lock Sleeve [22]
Striker [27]
Cylinder [19]
Bevel Gear [25]
Clutch Spring [23]
Clutch [24]
Fig. 6

-15-
2. Application of lubricant
• Filling special grease (for the hammer and hammer drill)
In the Cylinder Case [7]: 15 g
Connecting Rod [31] side in the Crank Case [70]: 50 g
• Application of special grease (for the hammer and hammer drill)
Apply special grease to the inner circumferences of the Cylinder [19] and Connecting Rod [31], the
sliding portion of the Second Hammer [15], the O-ring (C) [14] wound around the Second Hammer [15],
the sliding portion of the Striker [27], the O-ring [28] wound around the Striker [27] and Piston [30], the lip
portions at the inner circumference of Oil Seal (A) [53] and Oil Seal (B) [77], the inner and outer
circumferences of the Bevel Gear [25], the inner circumference of metal in the Cylinder Case [7], and the
lip portions at the inner circumference of oil seals in the Cylinder Case [7], Damper [17] and Retainer
Damper [10].
• Filling Hitachi Motor Grease No. 29
First Gear [78] side and Gear Cover [80] side in the Crank Case [70]: 30 g in total
• Application of Hitachi Motor Grease No. 29
Pinion portions of the Needle Bearing M661 [79], Armature Ass'y [43] and Needle Roller D8 x 20 [13]
3. Tightening torque
Apply screw locking agent TB1401 to all hex. socket head bolts M4, M5 and M6.
NOTE:
Be sure to apply screw locking agent (Three Bond TB1401) to the threads during reassembly.
Otherwise, any bolts loosened due to vibration may damage the tool body.
M6 • Seal Lock Hex. Socket Hd. Bolt M6 x 45 [65]
(For mounting the housing) -------------------------------- 9.8 ± 0.98 N•m (100 ± 10 kgf•cm)
• Seal Lock Hex. Socket Hd. Bolt M6 x 20 [64]
(For mounting the gear cover) ----------------------------- 9.8 N•m (100 kgf•cm)
• Hex. Socket Hd. Bolt (W/Flange) M6 x 25 [8]
(For mounting the cylinder case) ------------------------- 9.8 N•m (100 kgf•cm)
M5 • Hex. Socket Hd. Bolt (W/Flange) M5 x 16 [67]
(For mounting the crank cover) --------------------------- 7.84 N•m (80 kgf•cm)
• Hex. Socket Hd. Bolt (W/Flange) M5 x 16 [67]
(For mounting the handle) ---------------------------------- 5.88 N•m (60 kgf•cm)
M4 • Seal Lock Hex. Socket Hd. Bolt M4 x 12 [32]
(For mounting the change lever) -------------------------- 4.41 ± 0.49 N•m (45 ± 5 kgf•cm)
• Tapping Screw (W/Flange) D5 ------------------------------ 2.94± 0.49 N•m (30 ± 5 kgf•cm)
• Tapping Screw (W/Flange) D4 ------------------------------ 1.96± 0.49 N•m (20 ± 5 kgf•cm)
+1.96
0
+20
0
+1.96
0
+20
0
+1.96
0
+20
0
+1.96
0
+20
0

-16-
4. Internal wiring
(1) Wiring diagram for products without a noise suppressor
(2) Wiring diagram for products with a noise suppressor
5. Insulation tests
Upon the completion of disassembly and repair, measure the insulation resistance and dielectric strength.
Insulation resistance: 7M or more using a 500 VDC megohm tester
Dielectric strength: 4,000 VAC/minute, with no abnormalities (220 to 240 V)
(110VforU.K.products)
2,500 VAC/minute, with no abnormalities (110 to 127 V)
(ExceptforU.K.products)
6. No-load current value
After no-load operation for 30 minutes, the no-load current values should be as follows:
Voltage (V) 110 120 220 230 240
Current (A) max. 6.4 5.9 3.2 3.1 2.9
Switch (C) (1P screw type) w/o lock
Stator ass’y
Plug
A
rmature ass’y
Connector or Pillar Terminal
A
Noise
Suppressor
Switch (C) (1P screw type) w/o lock
Stator ass’y
Plug
A
rmature ass’y
Pilla
r
Terminal
A
Connecto
r
Connecto
r

-17-
MODEL Variable
Fixed 10 20 30 40 50 60
Work Flow
Handle Cover
Switch (C)
Cord
Cord Armor
Tail Cover
Crank Cover
Change Lever
Lever Holder
Lever Shaft
Front Cap
Grip
Needle Holder
DH 38MS
General assembly
Cylinder Case
Retainer
Damper
Retainer
Sleeve
Second
Hammer
Damper
Handle
Cylinder
Lock Sleeve
Clutch
Striker
O-Ring
Gear Cover
Needle Bearing
Armature Ass’y
Ball Bearing
(6201
DDCMPS2L)
Dust Washer
(B)
Ball Bearing
(608
VVC2PS2L)
Crank Shaft
Ball Bearing
(6203
DDCMPS2L)
Oil Seal (B)
First Gear
Slip Clutch
Ass'y
Bevel Pinion
Oil Seal (A)
Ball Bearing
(6002
DDCMPS2L)
Washer (A)
Gear Holder
Second Gear
Ball Bearing
(629
VVC2PS2L)
Bevel Gear
Piston
Connecting Rod
Housing Ass'y
Stator Ass'y
Crank Case
STANDARD REPAIR TIME (UNIT) SCHEDULES