2. WWW.KITAGAWA.COM Chucks 101 Agenda Types of Chucks Grip Force
Maintenance
Jaws
Special applications

3. Types of Chucks
Thru hole style
Closed center
Wedge
Lever
Self Contained Air
Pullback

4. Thru Hole style chuck Bar Feed Chucker Work Accurate Durable
High Speed
High Grip Force
Wide Range Of Application
Most Common
Body Is High Grade Alloy Steal
All Wear Surfaces Are Hardened And Ground

5. Closed Center Style Chuck
Chucker Work
Accurate
Durable
High Speed
High Grip Force
Wide Range Of Application
Body Is High Grade Alloy Steal
All Wear Surfaces Are Hardened And Ground

6. Wedge Style Chuck Master Jaws
Interaction between angle on master jaw to angle on wedge plunger. 2 “wedge” surfaces interacting to give motion and mechanical advantage.
Wedge Plunger

7. Lever Style Chuck

8. PW & PWT (BALL LOCK) STYLE PULLBACK CHUCKS
STANDARD
* PW series (3 Jaw)
*PWT series (2 Jaw)
COMPENSATING
*PW-C series (3 Jaw)
*PWT-C series (2 Jaw)
ADVANTAGES
OD OR ID GRIPPING
PULL BACK CHUCK – NO WORKPIECE LIFTING
COMPLETELY SEALED
CHUCK ON UPTO 20 DEGREE DRAFT ANGLE
JAWS EQUALIZE UPTO 5 DEGREES
EXCELLENT FOR 1st OPERATIONS

9. Special Features Of The PW(T) Chuck

10. SPECIAL FEATURES OF THE PU SERIES
PULL DOWN FEATURE – IDEAL FOR 2ND OPERATIONS REQUIRING HIGH PRECISION
HIGH GRIPPING FORCE RETENTION
HIGH ACCURACY (.0004”)
HIGH DURABILITY – ALL SLIDING SURFACES ARE HARDENED AND GROUND
COMPLETELY SEALED DESIGN

11. Inner Workings Of PU Chuck

12. SPECIAL FEATURES OF THE PUE SERIES
PULL DOWN FEATURE – IDEAL FOR 2ND OPERATIONS REQUIRING HIGH PRECISION
HIGH GRIPPING FORCE RETENTION
HIGH ACCURACY (.0004”)
HIGH DURABILITY – ALL SLIDING SURFACES ARE HARDENED AND GROUND
COMPLETELY SEALED DESIGN

13. PU200 MAIN PARTS
BODY
MASTER JAW
PLUNGER

14. THE PULL-DOWN MECHANISM

15. PU200 PLUNGER ASSEMBLY
THE MASTER JAW MOVES IN BOTH THE Y & Z AXES BECAUSE OF THE BODY’S ANGLE, WHILE THE PLUNGER JUST MOVES ALONG THE Z AXIS.

16. SPECIAL FEATURES OF THE UVE & UB SERIES
SELF CONTAINED AIR CHUCK
EASY INSTALLATION
EXTRA LARGE BORE – NO DRAWTUBE
BUILT IN CHECK VALVE
HIGH SPEED
UVE750

17. HOW THE UVE SERIES WORKS
PISTON
WEDGE PLUNGER
TOP JAW
MASTER JAW
AIR FLOWS IN
AIR FLOWS INTO THE CHUCK AND PUSHES ON THE PISTON.
THE PISTON DRAWS THE WEDGE PLUNGER IN OR OUT DEPENDING ON WHICH CAVITY THE AIR FILLS.
THE WEDGE PLUNGER MOVES AND CAUSES THE MASTER JAWS TO SLIDE IN OR OUT ALONG THE WEDGE.
AS THE MASTER JAWS MOVE ALONG THE WEDGE IN THE WEDGE PLUNGER THE TOP JAWS OPEN AND CLOSE.

18. Grip Force Is Affected By:
Speed (RPM) Of Chuck – As speed increases grip force decreases.
Jaw Height – As the gripping center height increases the grip force decreases.
Jaw Mass – As the mass of the top jaw increases the grip force decreases.
Chuck Condition - If the chuck has damage or excessive wear grip force can be impacted.
Lubrication – Proper chuck lubrication can increase grip force up to 50%.
Grip force and maximum rpm ratings are based on using Kitagawa soft jaws
WITH INCREASED HEIGHT

19. You can find this information for all our chucks at WWW.KITAGAWA.COM
Chuck Specifications 3 2 1
MECHANICAL ADVANTAGE = MAX GRIP FORCE/MAX DRAWBAR PULL FORCE
5812(Kgf)/2243(Kgf)=2.59(Kgf) MECHANICAL ADVANTAGE
2) CYLINDER STROKE MUST EQUAL OR EXCEED CHUCK PLUNGER STROKE
3) JAW STROKE IS ON DIAMETER. TO GET STROKE PER JAW DIVIDE BY 2
5.5mm/2 = 2.75mm STROKE PER JAW
You can find this information for all our chucks at

20. GRIP FORCE LOSS
DECREASED FORCE
WITH INCREASED SPEED

21. JAW HEIGHT VS. GRIPPING FORCE
DECREASED FORCE
WITH INCREASED HEIGHT

22. Jaw Mass Effect On Grip Force
A = B A B H
37 mm R A B
B-24
H: H * Grip Force = Grip Force * mm
Grip Force / H = New Grip Force
23,861 Kg * 37 mm = 23,861 * 37 = 882,857 Kg/mm
882,857 Kg/mm / 105 mm = Kg New Max Grip Force H *
A = B
Mass (M) = Kg
Mass Center Radius (R) = 254 mm
M * R * 3 = 7000

23. Gripping Coefficient Of Friction
TS = HOLDING FORCE (Kgf/mm) = (DYNAMIC GRIP FORCE * u (see table above) * GRIPPING DIAMETER)/2000
EXAMPLE: 200mm grip diameter, 3671 Kgf dynamic grip force, serrated fine axial grip with wedge chuck
TS = (3671 Kgf * .24 * 200mm)/2000 = Kgf/mm
TR = CUTTING TORQUE (Kgf/mm) = CUTTING DIAMETER (mm) * FEED RATE (mm/rev) * DEPTH OF CUT (mm) * MATERIAL CUTTING RESISTANCE (Kg/mm2) /2000
EXAMPLE: 300mm CUTTING DIAMETER, .100mm/rev FEED RATE, 1.5mm DEPTH OF CUT, MATERIAL IS LOW CARBON STEEL (367.2 Kg/mm2)
TR = (300mm * .100mm *1.5 * 367.2) / 2000 = Kgf/mm
TS/TR = SAFETY FACTOR /8.262 = SAFETY FACTOR YOU WANT AT LEAST 2.5

24. Other Factors That Affect Cutting Torque
Workholding
Gripping Diameter
Friction Coefficient ( u )
Gripping Force
Cutting Conditions
Cutting Diameter
Depth Of Cut
Feed Rate
Material Cutting Resistance
Speed
Items In Red Can Be Altered To Suite The Application
Other Aspects
1) Gripping Accuracy
Toppling Moment Of Part
Part Pushback Force From Cut
Imbalance Of System (Part & Chuck) - Vibration
Rigidity Of System (Chatter)

25. Chuck Maintenance
Greasing The Chuck Not Only Lubricates, But Also Helps Remove Contamination From The Chuck
Proper Lubrication Can Prevent The Loss Of Up to 50% Of A Chucks Grip Force

26. How CHUCK-EEZ Works

27. Comparison Of Grip Force With CHUCK-EEZ and Lithium Grease
With CHUCK-EEZ Grease You have More Grip Force At 5000 RPM Than Lithium Grease Has At 0 RPM

28. Chuck Maintenance – Periodic Disassembly
Clean
Inspect
BENEFITS
Increase Chuck Life
Decrease Unplanned Downtime
Safety
Maintain chuck performance and accuracy

29. Jaws
Jaw Lift – Sliding jaw chucks will impart a slight lift when they clamp.
Forming Soft Jaws – Form soft jaws under clamp load
T-Nut Position – There is a maximum front and back position.
Potential Problems With Aftermarket Jaws – If the serrations are not made correctly it can cause wear issues and grip force problems.

30. Jaw Lift In Sliding Jaw Chucks
THE SLIDING JAW STYLE POWER CHUCKS OPEN AND CLOSE WHEN THE MASTER JAWS SLIDES ALONG THE WEDGE PLUNGER’S FITTED SLOTS. THE FIGURE ABOVE SHOWS A CASE OF OD CLAMPING. THE MASTER JAWS MOVE UNTIL THE TOP JAWS TOUCH THE WORK PIECE. HOWEVER, THERE IS A GAP BETWEEN THE MASTER JAW TABS AND THE WEDGE PLUNGER’S SLOTS. SO IN ORDER FOR THE MASTER JAWS TO MAKE CONTACT WITH THE WEDGE PLUNGER THE JAWS WILL TILT WHEN THE WORK PIECE IS GRIPPED. THE INNER TOP AND OUTER BOTTOM OF THE MASTER JAWS TAB WILL CONTACT THE DOVETAIL GROOVES (SLOT) IN THE WEDGE PLUNGER. .
THE AMOUNT OF LIFT UP IS INCREASED BY THE FOLLOWING CONDITIONS:
HIGH GRIPPING FORCE
TALLER JAWS (HIGH GRIPPING CENTER HEIGHT)
SMALL GRIPPING DIAMETER

31. Forming Soft Jaws For A Sliding Jaw Chuck
Step 1
Step 4
Step 2
Step 5
Step 3

32. Why You Need To Reform Soft Jaws After Removal
EVEN IF YOU RE-MOUNT THE TOP JAWS THAT WERE MADE ON THE CHUCK AT THE SAME POSITION, THE GRIPPING ACCURACY WILL MOST LIKELY BE WORSE THAN BEFORE THE REMOVAL OCCURED. IF YOU NEED THE ACCURACY TO REMAIN THE SAME AS BEFORE, YOU WILL NEED TO RE-CUT THESE JAWS ON THE CHUCK.
THE FIGURE SHOWS THE WORST CASE SCENARIO. TOP JAWS WERE FINISHED TOUCHING THE RIGHT-AND SIDE OF T-NUTS (AS SHOWN ON THE LEFT SIDE OF THE FIGURE). THEN, THEY WERE DETACHED AND RE-INSTALLED TOUCHING THE LEFT-HAND SIDE OF THE T-NUTS. IN THIS CASE, SINCE THERE IS A GAP BETWEEN THE T-NUT AND THE TOP JAWS, THE POSITION OF THE TOP JAWS IS NOT COMPLETELY THE SAME. THIS IS THE CAUSE FOR THE DETERIORATION OF ACCURACY.

33. T-Nut Positioning

34. Serrations Need To Properly Mate Up Between The Master Jaw And Top Jaw
COMMERCIAL SOFT JAW ISSUES
IMPROPER CHAMFERING
IMPROPER PITCH
Serrations Need To Properly Mate Up Between The Master Jaw And Top Jaw

35. COMMERCIAL VS. PRECISION SOFT JAWS

36. COMMERCIAL VS. PRECISION SOFT JAWS ON CHUCK SURFACE

37. Special Applications
Some Parts Will Not Run Productively Or Accurately On Standard Chucks and Workholding. In These Instances We Would Utilize PW, PU Or Other Types Of Pullback Chucks. Some Parts May Also Be More Suited To An Indexing Chuck.
Advantages Of Specialized Workholding
Achieve Higher Output
Improve Accuracy To Meet Statistical Process Controls
Lower Maintenance
Suitable For Automated Loading
Engineered To Meet The Needs Of A Specific Part And Process