Kitagawa BS300 User manual

Version 1.10 (2021.08.03)
Original instructions
INSTRUCTION MANUAL
BS300 type
Large Thru-Hole High Precision Power Chuck
Kitagawa Corporation
77-1,Motomachi,Fuchu-shi,Hiroshima,726-8610,Japan
TEL [phone]
FAX [phone]
・This instruction manual is for production engineers and maintenance
personnel in charge of operation of this product. When a beginner uses
this product, receive instructions from experienced personnel, the
distributor or our company.
・Before installing, operating or maintaining this equipment, carefully
read this manual and the safety labels attached to the equipment.
Failure to follow these instructions and safety precautions could result
in serious injury, death, or property damage.
・Store this manual near equipment for future reference.
・If any questions related to safety arise about this manual, please
confirm them with the distributor or our company.
DANGER

1
Preface
This manual provides detailed information about how to safely and correctly use the power
chuck (BS300 type) for a lathe.
Before starting to use this power chuck, read this manual carefully and always follow the
instructions and warnings in "Important Safety Precautions" and "Precautions for Use"
at beginning of the manual. Failure to follow these precautions could result in a serious
accident.
Terms and Symbols Used for Safety Messages
In this manual, precautions for handling that are considered especially important are
classified and displayed as shown below depending on the damage of risk including the
seriousness of the harm that could result. Please sufficiently understand the meanings of
these terms and follow the instructions for safe operation.
Safety Alert Symbol
The triangle is the safety alert symbol used to alert you to potential safety hazards that
could result in injury or death.
Indicates a hazardous situation which, if you not avoided, will
result in death or serious injury.
Indicates a hazardous situation which, if you not avoided,
could result in death or serious injury.
Indicates a hazardous situation which, if you not avoided,
could result in minor or moderate injury.
Indicates instructions which, if not avoided, could result in
damage to the equipment or a shortened work life.

2
Liability and How to Use this Manual
This product is suitable for gripping a workpiece on the lathes or rotary tables. This product
is equipped with the jaws to clamp the workpiece and they operate by means of a rotary
cylinder. For any other applications, please contact us.
Our company will not assume responsibility for injury, death, damage, or loss resulting from
not following the instructions in this manual.
There are countless things that cannot or should not be done, and it is impossible to cover
all of them in this manual.
Therefore, do not perform any actions unless they are specifically allowed in this manual. If
any questions related to safety arise about operation, control, inspection and maintenance
which are not specified in this manual, please confirm them with our company or distributor
before performing them.
Guarantee and Limitation of Liability
The guarantee period of this product is 1 year after delivery.
Use the parts delivered by Kitagawa Corporation for all the parts including consumable
parts. We will not assume responsibility for injury, death, damage, or loss caused by usage
of parts not manufactured by Kitagawa Corporation. Additionally, if parts other than genuine
parts manufactured by Kitagawa Corporation are used, this guarantee will be completely
invalid.
The chuck and cylinder from Kitagawa Corporation should be used together. If you must
use a part not made by Kitagawa, check with us or our distributor to be sure it is safe to do
so. We will not be responsible for injury, death, damage or loss caused by use of a chuck
or cylinder made by another company unless this use has been approved by Kitagawa or
its distributor.

3
Table of Contents
1. Structural Drawing and Parts List -----------------------------------------------------------------------5
1-1. Type display
1-2. Structural drawing
1-3. Scope of product
1-4. Parts list
2. Important Safety Precautions ------------------------------------------------------------8
3. Specifications ----------------------------------------------------------------------------------------------15
3-1. Specifications
3-2. Relationship between gripping force and rotation speed
3-3. Relationship between gripping part center height, static griping force and input
force / Relationship between top jaw mass moment and gripping force loss
4. Forming Soft Jaw ------------------------------------------------------------------------------------------23
4-1. Attachment of soft jaw
4-2. Forming soft jaw with outside diameter gripping
4-3. Forming soft jaw with inside diameter gripping
4-4. Forming method when you use forming jig
5. Usage --------------------------------------------------------------------------------------------------------28
5-1. Precautions during gripping work with chuck
5-2. Precautions during gripping work in irregular shape
5-3. Precautions related to usage of jaw
5-4. Precautions related to processing
5-5. Attachment of locator and jig
6. Maintenance and Inspection ---------------------------------------------------------------------------32
6-1. Periodic Inspection
6-2. Grease lubrication
6-3. Disassembling
7. Malfunction and Countermeasures ------------------------------------------------------------------35
7-1. In the case of malfunction
7-2. Where to contact in the case of malfunction

4
For Machine Tool Manufacturers (Chapter 8)
8. Attachment -------------------------------------------------------------------------------------------------37
8-1. Outline drawing of attachment
8-2. In the case that the back plate must be manufactured (BS300 series)
8-3. In the case of with back plate (BS300A series)
8-4. Attachment of chuck
9. Other Information ----------------------------------------------------------------------------------------48
9-1. About standards and orders
9-2. Information about markings of product
9-3. About disposal

5
1. Structural Drawing and Parts List
1-1. Type display
Type display as shown below
Fig.1
1-2. Structural drawing
Fig.2

6
1-3. Scope of product
This instruction manual is for the chuck part.
Fig.3
・To prevent the work from flying, safe design, maintenance and erroneous
action prevention of the hydraulic system to maintain the gripping force of the
chuck is extremely important. Thoroughly read the “Important Safety
Precautions”on and after page 8 in this manual.
・As for the cylinder, follow the instruction manual for the cylinder.

7
1-4. Parts list
Fig.4
Table 1
No.
Part name
Quantity
No.
Part name
Quantity
1
Body
1
14
Chuck attaching bolt
3
2
Wedge plunger
3
15
Set screw
1
3
Master jaw
3
16
Set screw
2 or 4
4
Soft jaw
3
17
Socket head cap screw
3
5
T nut
3
18
Steel ball
1
6
Plunger
1
19
Grease nipple
6
7
Plunger nut
1
20
Hex key
1
8
Draw nut
1
21
Hex key
1
9
Cover
1
22
Hex key
1
10
Coil spring
1
23
Hex key
1
11
Handle
1
24
Felt
6
12
Socket head button screw
3
25
Back plate
1
13
Jaw attaching bolt
6
26
Socket head cap screw
3
25, 26 are only supplied if there is a back plate.

8
2. Important Safety Precautions
Important safety precautions are summarized below. Please read this section before first
starting to use this product.
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Turn off main power supply before attaching, inspecting or replacing
chuck, and before adding oil.
・The chuck may start rotation
suddenly, and a part of the body or
clothing may be caught.
Close door before rotating spindle.
・If the door is not closed, you may touch
the rotating chuck or the work may fly out,
which is very dangerous. (In general, the
safety interlock function which allows
rotation only when the door is the manual
mode or the test mode)
During spindle rotation, do not turn off hydraulic pump power supply and
do not operate switching valve.
・Cutting off hydraulic pressure
causes a drop in the gripping
force which could result in the
work being released and flying
out.
・Operating the manual switching
valve or solenoid valve will lead
to a drop of hydraulic pressure.
！
For All Users
For All Users
For All Users

9
Important Safety Precautions
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Do not allow the rotation speed of the chuck to exceed the maximum
allowable speed limit. (Refer to pages 17-22)
・If the rotation speed of the chuck
exceeds the rotation speed limit,
this is very dangerous as the
chuck and work will fly out.
The input force of the chuck (piston thrust, pulling force of the draw pipe)
must not exceed the allowable maximum input force.
(Refer to pages 17-22)
・Input must match the specification of the
chuck.
・Adjust the hydraulic pressure to the
cylinder so that the input force, which
determines the gripping force of the
chuck, does not exceed.
・Excessive input force can lead to
breakage of the chuck, which is very
dangerous, as the chuck can work can
be damaged and fly out.
If you use the chuck with the inside diameter gripping, input force
(hydraulic pressure) must be 1/2 or less of the allowable maximum input.
(Refer to page 22)
・The chuck may break and
the chuck or work could fly
out.
！
For All Users
For All Users
For All Users

10
Important Safety Precautions
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Keep the height of the jaw within the range specified in the gripping force
limit table (Refer to page 21). If you must use a jaw taller than a standard
soft jaw, use less than the input (piston thrust force, draw pipe drawing
force) specified in the gripping force limit table.
・Do not use a jaw of a height out
of the range of the gripping force
limit table or a jaw with mass
moment out of the range of the
gripping force limit table. The
chuck will break and the chuck
and work will break and fly out.
When the protrusion of the work is long, support it with the steady rest or
center.
・If the protrusion is long, the tip of the work can turn and the work fly out.
Determine the gripping force required for processing by the machine tool
manufacturer or user, and check that the required gripping force is
provided before processing.
(Refer to pages 17-22 and cylinder manual)
・Adjust the hydraulic pressure to the
cylinder to obtain the required gripping
force. If the gripping force is insufficient,
this is dangerous as the work will fly out.
！
For All Users
For All Users
For All Users

11
Important Safety Precautions
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Use of a chuck and cylinder that cannot be used together safely may
cause the cylinder to break at high pressure resulting in the chuck and
work flying out.
・Check that the chuck and the cylinder are in the “safe combination” when using at high
pressure with our company or the distributor. Especially when the cylinder of our
company and a high pressure chuck of other company are combined, confirmation is
necessary.
・If one of the abnormal events shown below occurs during operation, immediately stop
the machine and consult with our company or the distributor.
・The work slips.
・Loss of accuracy.
・The work begins to chatter.
・The machine's vibration significantly
increases.
・The griping force does not rise even if
hydraulic pressure is raised.
In the case of processing a significant unbalanced work, lower the
rotation speed.
・Unbalanced work generates dangerous centrifugal forces and the work could fly out.
！
For All Users
For All Users

12
Important Safety Precautions
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Always tighten the bolts at the specified torque. If the torque is
insufficient or excessive, the bolt will break, which is dangerous as the
chuck or work will fly out. Use the bolts attached to the chuck, and do not
use bolts other than these.
・If the torque is insufficient or
excessive, the bolt will break, which
is dangerous as the chuck or work
will fly out.
・Fix the lathe spindle or the chuck
when you tighten bolts. Your hand
could slip and get injury when you
work without fixing the spindle.
・You cannot control the torque by a
hex key. You must use a torque
wrench for torque control.
・Tightening torque is moment of force when you tighten a bolt. Tightening torque= F×L.
Specified torque for
socket head cap screw
Bolt size
Tightening torque
M5
7.5
N・m
M6
13
N・m
M8
33
N・m
M10
73
N・m
M12
107
N・m
M14
171
N・m
M16
250
N・m
M20
402
N・m
！
For All Users

13
Important Safety Precautions
DANGER
Failure to follow the safety precautions below will result in
serious injury or death.
Provide sufficient strength for the draw pipe (Refer to pages 39-41).
Provide sufficient screw depth for the draw pipe.
Firmly tighten the draw pipe.
・If the draw pipe break, the gripping force is instantly
lost and this is dangerous as work will fly out.
・If the screw depth of the draw pipe is insufficient, the
screw will break and the gripping force will be lost
instantly, and this is dangerous as work will fly out.
・If the engagement of the screw of the draw pipe is
loose, vibration may occur resulting in breakage of
the screw. If the screw breaks, the gripping force will
be lost instantly, which is dangerous as the work will
fly out.
・If the draw pipe is unbalanced, vibration occurs, the
screw is broken and the gripping force will be lost
instantly, which is dangerous as the work will fly out.
Use a cylinder with a lock valve (safety valve, check valve) incorporated in
case of sudden hydraulic pressure drop due to blackout, malfunction of
the hydraulic pump, etc. Further, use a solenoid valve with a circuit that
retains the gripping position when no current is carried.
・If the hydraulic pressure
suddenly drops due to blackout
or malfunction of the hydraulic
pump, etc., this is dangerous
as work will fly out.
・Lock valve retains the hydraulic
pressure inside the cylinder
temporarily, when the hydraulic
pressure suddenly drops due
to blackout or malfunction of
the hydraulic pump, etc.
For Machine Tool Manufactures
！
For Machine Tool Manufactures

14
Important Safety Precautions
WARNING
Failure to follow the safety precautions below could result in
serious injury or death.
Do not modify the chuck in a way not permitted by the manufacturer.
・It may not only break the chuck but the chuck
and the work may fly out, which is dangerous.
・If you attach a locator or jig on the chuck body
surface, only process work in an acceptable
range (Refer to page 31).
Periodically supply adequate grease (Refer to page 32). Turn off power
before adding grease.
・Insufficient grease supply lowers the gripping
force, causes operation failure due to lower
hydraulic pressure, lowers the gripping precision,
and causes abnormal wearing and seizing, etc.
・This is dangerous as the work could fly out from
a drop in the gripping force.
Do not operate the machine
after drinking alcohol or taking
medication.
Do not operate the machine wearing
gloves, a necktie, and other loose
clothing or
jewelry.
・Dangerous since
these lead to
operation mistakes
and misjudgment.
・Dangerous since
it will be caught.
Do not grip a chuck with a chuck.
・Because it is easy to confuse the specifications of
each chuck and the protrusion become long and is
apt to raise rotation speed, it is apt to exceed the
specifications of the base chuck. The chuck may
break and the chuck or work could fly out.
！
For All Users
For All Users
For All Users
For All Users
For All Users

15
3. Specifications
3-1. Specifications
・BS300 type Table 2
Reference: 1kN = 101.97kgf 1MPa = 10.197kgf/cm2
When storing this product, the product should be subjected to the antirust treatment and
stored in a place free from wetting, condensation, or freeze.
Type
BS306
BS308
BS310
Plunger stroke
mm
12
14
17
Jaw stroke (in diameter)
mm
5.5
7.5
9.1
Allowable maximum
input force
kN
(kgf)
22
（2243）
34.8
(3549)
43
(4385)
Maximum static gripping force
kN
(kgf)
55
(5610)
84
(8570)
105.8
(10795)
Allowable maximum
Rotation speed
min-1
6000
5000
4200
Thru-hole diameter
mm
45
52
75
Standard soft jaw height
(Z axis)
mm
29
39
43
Gripping range
(outside diameter gripping)
mm
φ26~169
φ19~210
φ34~254
Mass
(standard soft jaw included)
kg
11.5
22.5
34.5
Moment of inertia
Kg・m2
0.06
0.13
0.33
Matching cylinder
S1246
S1552
S1875
Maximum hydraulic pressure
(with matching cylinder)
MPa
(kgf/cm2)
2.8
(28.6)
2.65
(27)
2.7
(27.5)
Balance quality
(standard soft jaw not included)
Ｇ6.3
Storing temperature /
Operating temperature
-20 ~+50 °C / -10 ~+40 °C

16
・BS300A type Table 3
Reference: 1kN = 101.97kgf 1MPa = 10.197kgf/cm2
When storing this product, the product should be subjected to the antirust treatment and
stored in a place free from wetting, condensation, or freeze.
Type
BS306A5
BS308A6
BS310A6
BS310A8
Plunger stroke
mm
12
14
17
17
Jaw stroke (in diameter)
mm
5.5
7.5
9.1
9.1
Allowable maximum
input force
kN
(kgf)
22
（2243）
34.8
(3549)
43
(4385)
43
(4385)
Maximum static gripping
force
kN
(kgf)
55
(5610)
84
(8570)
105.8
(10795)
105.8
(10795)
Allowable maximum
Rotation speed
min-1
6000
5000
4200
4200
Thru-hole diameter
mm
45
52
75
75
Standard soft jaw height
(Z axis)
mm
29
39
43
43
Gripping range
(outside diameter gripping)
mm
φ26
~169
φ19
~210
φ34
~254
φ34
~254
Mass
(standard soft jaw included)
kg
12.7
24.4
40.3
37.8
Moment of inertia
Kg・m2
0.06
0.14
0.37
0.35
Matching cylinder
S1246
S1552
S1875
S1875
Maximum hydraulic pressure
(with matching cylinder)
MPa
(kgf/cm2)
2.8
(28.6)
2.65
(27)
2.7
(27.5)
2.7
(27.5)
Balance quality
(standard soft jaw not included)
G6.3
Storing temperature /
Operating temperature
-20 ~+50 °C / -10 ~+40 °C

17
3-2. Relationship between gripping force and rotation speed
1. Maximum static gripping force
The static gripping force is the gripping force when the chuck is at a stop.
The power chuck has a mechanism to convert input force (piston thrust force, draw pipe
drawing force) from the cylinder to gripping force. Therefore, the gripping force when the
allowable maximum input force becomes the maximum static gripping force.
However, the gripping force is different depending on the state of grease lubrication, grease
in use, height of the jaw, etc. The maximum static gripping force specified in the
specification is the value under the following conditions:
・The Kitagawa standard soft jaw is used as the jaw.
・The attaching bolts of the soft jaw are tightened at the specified torque. (Refer to page
12)
・The numerical values are obtained with the Kitagawa gripping force meter . The gripping
position of the gripping force meter is at a position 1/2 of the height of the soft jaw top
surface (height from the chuck surface to the top surface of the jaw).
・CHUCK GREASE PRO is used. (Refer to page 32).
・A variable displacement pump with the discharge volume of 20 liters/min or more is
used as the hydraulic source. The pressure is set by the pressure control equipment of
the pump itself, or the pressure reduction valve equipped separately.
Fig.5

18
2. Allowable maximum rotation speed
In the case of outside diameter gripping, when the chuck is rotated, the gripping force
lowers due to the centrifugal force of the top jaw. Therefore, the rotation speed when the
dynamic gripping force (gripping force during rotation) becomes approximately 1/3 of the
maximum static gripping force is set as the allowable maximum rotation speed. The
centrifugal force is different depending on the mass of the top jaw and the barycentric
position as well as the rotation speed. The allowable maximum rotation speed specified in
the specification is the value under the following conditions:
・The Kitagawa standard soft jaw is used.
・Grip the gripping force meter in the center of the jaw stroke, and at this point, the soft
jaw is attached at the position where the periphery side end of the soft jaw and the
chuck periphery are almost lined up.
・The numerical values are obtained by the Kitagawa gripping force meter. The gripping
position of the gripping force meter is at a position 1/2 of the height of the soft jaw top
surface (height from the chuck surface to the top surface of the jaw).
To avoid serious accidents caused by the chuck or work flying out:
・Determine the gripping force required for processing by the machine tool
manufacturer or user, and check that the required gripping force is provided
before processing. The gripping force of the chuck must not exceed the
maximum static gripping force.
・Determine the rotation speed required for processing by the machine tool
manufacturer or user based on the gripping force required for the processing.
The rotation speed at this point must not exceed the allowable maximum
rotation speed.
・When determining the cutting conditions, refer to pages 19-22.
・Pay attention since the gripping force is different depending on the state of the oil
supply, grease in use, height of the jaw, performance of the pump and the pressure
reducing valve, piping state, etc.
3. Relationship between gripping force and rotation speed
As the rotation speed becomes higher, the centrifugal force of the jaw increases and the
gripping force lowers. The curves displayed in Fig. 6 shows relationships between the
rotation speed and the centrifugal force when using the standard soft jaw. The centrifugal

19
force differs significantly depending on the size and shape of the top jaw and the attaching
position, therefore, when the rotation speed is high, actual measurement using a Kitagawa
gripping force meter is required.
Fig.6
・In the case of processing a considerably unbalanced work, lower the rotation
speed. The work will fly out and this is dangerous.
・Vibration is generated if there is unbalance due to the work and the jig, etc.
Vibration decreases process precision and shortens the working life of the
chuck, even possibly breaking it. Correct the unbalance by using a balance
weight, etc., or lower the rotation speed for use.
・In the case of heavy cutting at high rotation speed, vibration is easily
generated in the same manner as the unbalance of the chuck, therefore, set
the cutting conditions appropriate for the dynamic gripping force and machine
rigidity.