dry bearings - · pdf file · 2014-02-17industry’s quality management system...

DU/DUBDry Bearings

Designer´s Handbook

I

QualityAll the products described in this handbook are manufactured under DIN EN ISO 9001, ISO/TS 16949 and ISO 14001approved quality management systems.In addition GGB North America has been certified AS9100 revision B complying with the requirements of aerospaceindustry’s quality management system for the manufacture of metal-backed bearings and filament wound bearings andwashers.

AMERICA

FRANCE

GERMANY

BRAZIL SLOVAKIA

CHINA

Technical approvals:Tested and approved by MPA Stuttgart (for DU®B) for structural bearings for civil engineering applications.

II

Formula Symbols and Designations

FormulaSymbol Unit Designation

A mm² Surface Area of DU bearing

AM mm² Surface Area of mating surface in con-tact with DU bearing (slideway)

aB - Bearing size factor

aC - Application factor for bore burnishing or machining

aE - High load factor

aE1 - Specific load factor (slideways)

aE2 - Speed, temperature and material factor (slideways)

aE3 - Relative contact area factor (slideways)

aL - Life correction constant

aM - Mating surface material factor

aT - Temperature application factor

B mm Nominal bush width

C 1/min Dynamic load frequency

CD mm Installed diametral clearance

Ci mm ID chamfer length

Co mm OD chamfer length

CT - Total number of dynamic load cycles

DC mm Diameter of burnishing tool

Dfl mm Nominal bush flange OD

DH mm Housing Diameter

Di mm Nominal bush and thrust washer ID

Di,a mm Bush ID when assembled in housing

DJ mm Shaft diameter

DNth nvt Max. thermal neutron dose

Do mm Nominal bush and thrust washer OD

Dγ Gy Max. Gamma radiation dose

dch,1 mm Checking block diameter

dD mm Dowel hole diameter

dL mm Oil hole diameter

dP mm Pitch circle diameter for dowel hole

F N Bearing load

Fch N Test force

Fi N Insertion force

f - friction

Ha mm Depth of Housing Recess(e.g. for thrust washers)

Hd mm Diameter of Housing Recess(for thrust washers)

L mm Strip length

LH h Bearing service life

LS mm Length of stroke (slideway)

N 1/min Rotational speed

Nosz 1/min Oscillating movement frequency

p N/mm² Specific load

plim N/mm² Specific load limit

psta,max N/mm² Maximum static load

pdyn,max N/mm² Maximum dynamic load

Q - Permissible number of cycles

Ra mm Surface roughness (DIN 4768, ISO/DIN 4287/1)

ROB Ω Electrical resistance

s3 mm Bush wall thickness

sfl mm Flange thickness

sS mm Strip thickness

sT mm Thrust washer thickness

T °C Temperature

Tamb °C Ambient temperature

Tmax °C Maximum temperature

Tmin °C Minimum temperature

U m/s Sliding speed

W mm Strip width

WU min mm Minimum usable strip width

ZT - Total number of cycles

α1 1/106K Coefficient of linear thermal expansion parallel to surface

α2 1/106K Coefficient of linear thermal expansion normal to surface

σc N/mm² Compressive Yield strength

λ W/mK Thermal conductivity

ϕ ° Angular displacement

η Ns/mm² Dynamic Viscosity

FormulaSymbol Unit Designation

III

HistoricalThe development of a polytetrafluoroethylene (PTFE) lined composite dry bearing material was first begun by the GlacierMetal Company Ltd in 1948 and patents were subsequently granted for the material during the 1950's. Today DU® is the most successful of composite bearing materials, combining the excellent dry bearing properties of PTFEwith the mechanical properties of conventional metallic bearings, and has a wider range of performance and greater num-ber of applications than probably any other bearing material.

3

Content

Content

Quality . . . . . . . . . . . . . . . . . . . . . IFormula Symbols andDesignations . . . . . . . . . . . . . . . . IIHistorical . . . . . . . . . . . . . . . . . . III

1 Introduction . . . . . . . . . . . 51.1 Applications . . . . . . . . . . . . . . . . 51.2 Characteristics and

Advantages . . . . . . . . . . . . . . . . 51.3 Basic Forms Available . . . . . . . 51.4 Materials . . . . . . . . . . . . . . . . . . . 6

2 Material . . . . . . . . . . . . . . . 72.1 Structure . . . . . . . . . . . . . . . . . . . 72.2 Dry Wear Mechanism . . . . . . . . 72.3 Physical, Mechanical

and Electrical Properties . . . . . . 92.4 Chemical Properties . . . . . . . . 10

Electrochemical Corrosion . . . . . 102.5 Frictional Properties . . . . . . . . 10

3 Performance . . . . . . . . . 123.1 Design Factors . . . . . . . . . . . . . 12

Calculation . . . . . . . . . . . . . . . . . 123.2 Specific Load p . . . . . . . . . . . . 123.3 Specific Load Limit plim . . . . . . 133.4 Sliding Speed U . . . . . . . . . . . . 13

Continuous Rotation . . . . . . . . . 13Oscillating Movement . . . . . . . . 13

3.5 pU Factor . . . . . . . . . . . . . . . . . 143.6 Application Factors . . . . . . . . . 14

Temperature . . . . . . . . . . . . . . . 14Mating Surface . . . . . . . . . . . . . . 15Bearing Size . . . . . . . . . . . . . . . 15Bore Burnishing . . . . . . . . . . . . . 16Type of Load . . . . . . . . . . . . . . . 16

3.7 Calculation of Bearing Size . . 17Calculation for Bushes . . . . . . . . 17Calculation for Thrust Washers 17Calculation for Slideways . . . . . 17

3.8 Calculation of BearingService Life . . . . . . . . . . . . . . . . 18Specific load p . . . . . . . . . . . . . . 18High load factor aE . . . . . . . . . . 18Modified pU Factor . . . . . . . . . . 18Estimation of bearing life LH . . . . 19Bore Burnishing . . . . . . . . . . . . . 19Slideways . . . . . . . . . . . . . . . . . . 19

3.9 Worked Examples . . . . . . . . . . 20

4 Data Sheet . . . . . . . . . . . 224.1 Data for bearing design

calculations . . . . . . . . . . . . . . . 22

5 Lubrication . . . . . . . . . . . 235.1 Lubricants . . . . . . . . . . . . . . . . . 235.2 Tribology . . . . . . . . . . . . . . . . . . 23

Hydrodynamic lubrication . . . . . . 23Mixed film lubrication . . . . . . . . . 24Boundary lubrication . . . . . . . . . 24

5.3 Characteristics ofLubricated DU bearings . . . . . . 24

5.4 Design Guidance forLubricated Applications . . . . . 24

5.5 Clearances forlubricated operation . . . . . . . . . 26

5.6 Mating Surface Finish forlubricated operation . . . . . . . . . 26

5.7 Grooving forlubricated operation . . . . . . . . . 26

5.8 Grease Lubrication . . . . . . . . . 26

6 Bearing Assembly . . . . . 27Dimensions and Tolerances . . . . 27

6.1 Allowance forThermal Expansion . . . . . . . . . 27

6.2 Tolerances forminimum clearance . . . . . . . . . 27Sizing . . . . . . . . . . . . . . . . . . . . . 28

6.3 Counterface Design . . . . . . . . . 286.4 Installation . . . . . . . . . . . . . . . . 29

Fitting of cylindrical bushes . . . . 29Fitting of flanged bushes . . . . . . 29Insertion Forces . . . . . . . . . . . . . 29Alignment . . . . . . . . . . . . . . . . . . 30Sealing . . . . . . . . . . . . . . . . . . . . 30

6.5 Axial Location . . . . . . . . . . . . . . 30Fitting of Thrust Washers . . . . . . 30Slideways . . . . . . . . . . . . . . . . . . 31

7 Modification . . . . . . . . . . 327.1 Cutting and Machining . . . . . . 32

Drilling Oil Holes . . . . . . . . . . . . . 32Cutting Strip Material . . . . . . . . . 32

7.2 Electroplating . . . . . . . . . . . . . . 32DU Components . . . . . . . . . . . . . 32Mating Surfaces . . . . . . . . . . . . . 32

4

Content

8 Standard Products . . . . 338.1 DU Cylindrical Bushes . . . . . . 338.2 DU Flanged Bushes . . . . . . . . 388.3 DU Flanged Washers . . . . . . . 408.4 DU Thrust Washer . . . . . . . . . 418.5 DUB Cylindrical Bushes . . . . . 428.6 DUB Flanged Bushes . . . . . . . 448.7 DU Cylindrical Bushes -

Inch sizes . . . . . . . . . . . . . . . . . 458.8 DU Thrust Washers -

Inch sizes . . . . . . . . . . . . . . . . . 49

8.9 DU Strip . . . . . . . . . . . . . . . . . . 508.10 DUB Strip . . . . . . . . . . . . . . . . . 508.11 DU Strip - Inch sizes . . . . . . . . 50

9 Test Methods . . . . . . . . . 519.1 Measurement of

Wrapped Bushes . . . . . . . . . . . 51Test A of ISO 3547 Part 2 . . . . . 51Test B (alternatively to Test A) . 51Test C . . . . . . . . . . . . . . . . . . . . 51Measurement of Wall Thickness(alternatively to Test C) . . . . . . . 51Test D . . . . . . . . . . . . . . . . . . . . 51

5

1Introduction

1 IntroductionThe purpose of this handbook is to providecomprehensive technical information onthe characteristics of DU® bearings. The information given permits designers toestablish the correct size of bearing requi-red and the expected life and performance. GGB Research and Development servicesare available to assist with unusual designproblems.Complete information on the range of DUstandard stock products is given togetherwith details of other DU products.

GGB is continually refining and extendingits experimental and theoretical knowledgeand, therefore, when using this brochure itis always worth-while to contact the Com-pany should additional information berequired. As it is impossible to cover all conditions ofoperation which arise in practice, custo-mers are advised to carry out prototypetesting wherever possible.

1.1 ApplicationsDU is suitable for • rotating, • oscillating, • reciprocating and • sliding movements.Also available are DU related materialcompositions for specific applications, for

example when increased corrosion resi-stance of the bearing material is requireddue to• atmospheric or environmental consider-

ations• food safety regulations

1.2 Characteristics and Advantages• DU requires no lubrication• Provides maintenance free operation• DU has a high pU capability• DU exhibits low wear rate• Seizure resistant• Suitable for temperatures from

-200 to +280 °C• High static and dynamic load capacity• Good frictional properties with negli-

gible stick-slip

• Resists solvents• No water absorption and therefore

dimensionally stable• DU is electrically conductive and

shows no electrostatic effects• DU has good embedability and is tol-

erant of dusty environments• Compact and light• DU bearings are prefinished and

require no machining after assembly

1.3 Basic Forms AvailableStandard Components available from stock. These products are manufactured to Inter-national, National or GGB standarddesigns.

Metric and Imperial sizes• Cylindrical Bushes• Flanged Bushes *• Thrust Washers

• Flanged Washers *• Strip Material* Metric sizes only

6

1 Introduction

Fig. 1: Standard Components

Non-Standard Components not available from stock. These products are manufactured tocustomers' requirements with or withoutGGB recommendations, and include forexample• Modified Standard Components

• Half Bearings• Flat Components• Deep Drawn Parts• Pressings• Stampings

Fig. 2: Non-Standard Components

1.4 Materials

Table 1: Characteristics of DU and DUB

Material Backing Bearing Lining

Operating Temperature [°C] Maximum Load plim

[N/mm2]Minimum Maximum

DU Steel PTFE+Lead -200 +280 250

DUB Bronze PTFE+Lead -200 +280 140

7

2Material

2 Material2.1 Structure

DUDU and DUB take advantage of the out-standing dry bearing properties of Polyte-trafluoroethylene (PTFE) and combinesthem with strength, stability and good wearresistance, excellent heat conductivity andlow thermal expansion.DU consists of three bonded layers: a steelbacking strip and a porous bronze matrix,impregnated and overlaid with the PTFE/lead bearing material.

Fig. 3: DU Microsection

DUBDUB also consists of three layers, with abronze backing replacing the steel backingstrip. The structure is otherwise the sameas that of DU. The bronze backing provides a high corro-sion resistance, anti magnetic propertiesand a good thermal conductivity.

Fig. 4: DUB Microsection

2.2 Dry Wear Mechanism

Fig. 5: Effect of wear on the DU bearing surface under dry operating conditions.

Rad

ial w

ear [

mm

]

Life LH [h]

0.01

0.02

0.04

0 2000 3000 4000

0.03

0

1000 5000

0.05

6000 7000

Bronze beginning to smear near end of material lifeFig. 8

Typical appearance after half material life Fig. 7

Running-in completed low wear rate starts when bronze is exposed Fig. 6

8

2 Material

Running-inDuring normal operation, a DU bearingquickly beds in and the PTFE/lead overlaymaterial removed during this period, typi-cally 0.015 mm, is transferred to themating surface and forms a physically bon-ded lubricant film. The rubbing surface of the bearing oftenacquires a grey-green colour and thebronze matrix can be seen exposed overabout 10 % of the bearing surface. Any

excess of the PTFE/lead surface layer willbe shed as fine feathery particles.

Fig. 6: Running-in

After 50 % of useful lifeFollowing the running-in period the wearrate reduces to a minimum and the per-centage of bronze exposed graduallyincreases.

Fig. 7: After 50 % of useful life

End of useful lifeAfter an extended period of operation thewear rate increases as the componentapproaches the end of its useful life as aself-lubricating bearing. At this stage atleast 70 % of the bearing surface will beexposed bronze, and approximately0.06 mm wear will have occurred.

Fig. 8: End of useful life

Wear of Mating SurfacesThere is no measurable wear of matingsurfaces made from recommended materi-als unless a DU bearing is operated

beyond its useful life or becomes contami-nated with abrasive dirt.

9

2Material

2.3 Physical, Mechanical and Electrical Properties

Table 2: Properties of DU and DUB

Characteristic SymbolValue

Unit CommentsDU DUB

Physical Properties

Thermal Conductivity λ 40 60 W/mK after running in.

Coefficient of linear thermal expansion : measured on strip 1.9 mm thick.

parallel to surface α1 11 18 1/106K

normal to surface α2 30 36 1/106K

Maximum Operating Temperature

Tmax +280 +280 °C

Minimum Operating Temperature

Tmin –200 –200 °C

Mechanical Properties Compressive Yield Strength σc 350 300 N/mm²

measured on disc 25 mm diameter x 2.44 mm thick.

Maximum Load

Static psta,max 250 140 N/mm²

Dynamic pdyn,max 140 140 N/mm²

Electrical Properties Surface Resistance ROB 1 – 10 1 – 12 Ω depends on applied pressure

and contact area

Nuclear Radiation Resistance

Maximum Thermal Neutron dose

DNth 2 x 1015 2 x 1015 nvt nvt = thermal neutron flux

Maximum gamma ray dose Dγ 106 106 Gy = J/kg 1 Gray = 1 J/kg

10

2 Material

2.4 Chemical PropertiesThe following table provides an indicationof the chemical resistance of DU and DUBto various chemical media. It is recommen-

ded that the chemical resistance is confir-med by testing if possible.

Table 3: Chemical Resistance of DU and DUB

Electrochemical CorrosionDUB should not be used in conjunctionwith aluminium housings due to the risk of

electrochemical corrosion in the presenceof water or moisture.

2.5 Frictional PropertiesDU bearings show negligible 'stick-slip'and provide smooth sliding between adja-cent surfaces. The coefficient of friction ofDU depends upon:• The specific load p [N/mm²]

• The sliding speed U [m/s]

• The roughness of the mating runningsurface Ra [µm]

• The bearing temperature T [°C].A typical relationship is shown in Fig. 9,which can be used as a guide to establishthe actual friction under clean, dry conditi-ons after running in. Exact values may vary by ± 20 % depen-ding on operating conditions.

Chemical % °C DU DUB

Strong Acids Hydrochloric Acid 5 20 - -Nitric Acid 5 20 - -Sulphuric Acid 5 20 - -

Weak Acids Acetic Acid 5 20 - oFormic Acid 5 20 - o

Bases Ammonia 10 20 o -Sodium Hydroxide 5 20 o o

Solvents Acetone 20 + +Carbon Tetrachloride 20 + +

Lubricants and Fuels

Paraffin 20 + +Gasolene 20 + +Kerosene 20 + +Diesel Fuel 20 + +Mineral Oil 70 o oHFA-ISO46 High Water Fluid 70 o oHFC-Water-Glycol 70 - -HFD-Phosphate Ester 70 o oWater 20 o +Sea Water 20 - o

+ Satisfactory: Corrosion damage is unlikely to occur.

oAcceptable: Some corrosion damage may occur but this will not be sufficient to impair either the structural integrity or the tribological performance of the material.

-Unsatisfactory: Corrosion damage will occur and is likely to affect either the structural integrity and/or the tribo-logical performance of the material.

11

2Material

Before running in, the friction may be up to50 % higher.With frequent starts and stops, the staticcoefficient of friction is approximately equalto, or even slightly less than the dynamiccoefficient of friction.After progressively longer periods of dwellunder load (e.g. hours or days) the static

coefficient of friction on the first movementmay be between 1.5 and 3 times greater,particularly before running in.Friction increases at bearing temperaturesbelow 0 °C. Where frictional characteristics are criticalto a design they should be established byprototype testing.

Fig. 9: Variation of friction coefficient f with specific load p and sliding speed U at temperature T = 25 °C

Fig. 10: Variation of friction coefficient f with specific load p and temperature T at sliding speed U = 0.01 m/s

0.30

0.25

0.20

0.15

0.10

0.05

00.1

1.0

10

100 0.00001

0.0001

0.001

0.01

0.1

1.0

1.5

2.0

2.5

0.25-0.30

0.20-0.25

0.15-0.20

0.10-0.15

0.05-0.10

0.00-0.05

Example

Specific loadp = 2.5 N/mm²Sliding speedU = 0.003 m/sFriction coefficientf = 0.14

Sliding speed U [m/s]

Specific load p [N/mm²]

Friction coefficient f

0.25

0.20

0.15

0.10

0.05

00.1

1.0

10

100 0

25

50

75

100

125

150

200

250

Example

Specific loadp = 2.5 N/mm²TemperatureT= 40 °CFriction coefficientf = 0.125

Specific load p [N/mm²]

Friction coefficient f

Temperature T [°C]

0.25-0.30

0.20-0.25

0.15-0.20

0.10-0.15

0.05-0.10

0.00-0.05

12

3 Performance

3 Performance3.1 Design FactorsThe main parameters when determiningthe size or calculating the service life for aDU bearing are:• Specific Load Limit plim• pU Factor

• Mating surface roughness Ra• Mating surface material • Temperature T • Other environmental factors e.g. hous-

ing design, dirt, lubrication

CalculationTwo design procedures are provided asfollows:• A bearing service life calculation based

on the permitted bearing dimensions

• A calculation of the necessary bearingdimensions based on the required bear-ing service life

3.2 Specific Load p For the purpose of assessing bearing per-formance the specific load p is defined asthe working load divided by the projected

area of the bearing and is expressed inN/mm².

Cylindrical Bush

Thrust Washer

Flanged Bush (Axial Loading)

Slideway

Permanent deformation of the DU bearinglining may occur at specific loads above140 N/mm² and under these conditions DUshould only be used with slow intermittentmovements.

The permissible maximum load on a thrustwasher is higher than that on the flange ofa flanged bush, and under conditions ofhigh axial loads a thrust washer should bespecified.

p FDi B⋅---------------=

(3.2.1) [N/mm²]

[N/mm²]

p 4Fπ Do

2 Di2–( )⋅

------------------------------=

(3.2.2)

p F0 04, Dfl

2 Di2–( )⋅

-----------------------------------------=

(3.2.3) [N/mm²]

0.04

p FL W⋅--------------=

(3.2.4) [N/mm²]

13

3Performance

3.3 Specific Load Limit plim The maximum load which can be appliedto a DU bearing can be expressed in termsof the Specific Load Limit, which dependson the type of the loading. It is highestunder steady loads. Conditions of dynamicload or oscillating movement which pro-duce fatigue stress in the bearing result ina reduction in the permissible SpecificLoad Limit.In general the specific load on a DU bea-ring should not exceed the Specific LoadLimits given in Table 4.The values of Specific Load Limit specifiedin Table 4 assume good alignment bet-ween the bearing and mating surface(Fig. 29).

Fig. 11: Projected Area

Maximum specific load plim

Table 4: Maximum specific load plim

3.4 Sliding Speed USpeeds in excess of 2.5 m/s sometimeslead to overheating, and a running in pro-cedure may be beneficial.

This could consist of a series of short runsprogressively increasing in duration froman initial run of a few seconds.

Calculation of Sliding Speed U [m/s]

Continuous RotationCylindrical Bush Thrust Washer

Oscillating MovementCylindrical Bush Thrust Washer

BDi

Projected Area

A = Di x B

Type of loading plim [N/mm2]

steady load, rotating movement 140

steady load, oscillating movement

plim 140 140 115 95 85 80 60 44 30 20

No. of movement cycles Q 1000 2000 4000 6000 8000 104 105 106 107 108

dynamic load, rotating or oscillating movement

plim 60 60 50 46 42 40 30 22 15 10

No. of load cycles Q 1000 2000 4000 6000 8000 104 105 106 107 108

U Di π N⋅ ⋅60 103⋅------------------------=

(3.4.1) [m/s]

U

Do Di+2

---------------- π N⋅ ⋅

60 103⋅-----------------------------------=

(3.4.2) [m/s]

UDi π⋅

60 103⋅--------------------- 4ϕ Nosz⋅

360----------------------⋅=

(3.4.3) [m/s]

U

Do Di+2

---------------- π⋅

60 103⋅------------------------- 4ϕ Nosz⋅

360----------------------⋅=

(3.4.4) [m/s]

14

3 Performance

3.5 pU FactorThe useful operating life of a DU bearing isgoverned by the pU factor, the product ofthe specific load p [N/mm2] and the slidingspeed U [m/s].For thrust washers and flanged bush thrustfaces the rubbing velocity at the mean dia-meter is used.pU factors up to 3.6 N/mm2 x m/s can beaccommodated for short periods, whilst forcontinuous rating.

pU factors up to 1.8 N/mm2 x m/s can beused, depending upon the operating liferequired.

Table 5: Typical data p, U and pU

Calculation of pU Factor [N/mm² x m/s]

3.6 Application FactorsThe following factors influence the bearingperformance of DU and must be conside-red in calculating the required dimension

or estimating the bearing life for a particu-lar application.

Temperature The useful life of a DU bearing dependsupon the operating temperature.Under dry running conditions frictional heatis generated at the rubbing surface of thebearing dependent on the pU condition.For a given pU factor the operating tempe-rature of the bearing depends upon thetemperature of the surrounding environ-

ment and the heat dissipation properties ofthe housing. Intermittent operation affectsthe heat dissipation from the assembly andhence the operating temperature of thebearing.The effect of temperature on the operatinglife of DU bearings is indicated by the fac-tor aT shown in Table 6.

Table 6: Temperature application factor aT

DU Unit

p 140 N/mm²

U 2.5 m/s

pU continuous 1.8 N/mm² x m/s

pU intermittent 3.6 N/mm² x m/s

pU p U⋅=

(3.5.1) [N/mm² x m/s]

Mode of Operation Nature of housing

Temperature of bearing environment Tamb [°C]and Temperature application factor aT

25 60 100 150 200 280

Dry continuous operation Average heat dissipating qualities 1.0 0.8 0.6 0.4 0.2 0.1

Dry continuous operation Light pressings or isolated housing with poor heat dissipating qualities 0.5 0.4 0.3 0.2 0.1 -

Dry continuous operation Non-metallic housings with bad heat dissi-pating qualities 0.3 0.3 0.2 0.1 - -

Dry intermittent operation (duration less than 2 min, followed by a longer dwell period)

Average heat dissipating qualities 2.0 1.6 1.2 0.8 0.4 0.2

Continuously immersed in water 2.0 1.5 0.6 - - -

Alternately immersed in water & dry 0.2 0.1 - - - -

Continuously immersed in non lubricant liquids other than water 1.5 1.2 0.9 0.6 0.3 0.1

Continuously immersed in lubricant 3.0 2.5 2.0 1.5 - -

15

3Performance

Mating SurfaceThe effect of the mating surface materialtype on the operating life of DU bearings isindicated by the mating surface factor aMand the life correction constant aL shown inTable 7.

Table 7: Mating surface factor aM and life correction constant aL

Note:The factor values given assume a matingsurface finish of ≤0.4 µm Ra • A ground surface is preferred to fine

turned• Surfaces should be cleaned of abrasive

particles after polishing

• Cast iron surfaces should be ground to<0.3 µm Ra

• The grinding cut should be in the samedirection as the bearing motion relativeto the shaft

Bearing SizeThe running clearance of a DU bearingincreases with bearing diameter resultingin a proportionally smaller contact areabetween the shaft and bearing. This reduc-tion in contact area has the effect of increa-sing the actual unit load and hence pU

factor. The bearing size factor (Fig. 13) isused in the design calculations to allow forthis effect. The bearing size factor is alsoapplicable to thrust washers, where forother reasons, bearing diameter has aneffect on performance.

Fig. 12: Contact area between bearing and shaft.

Material aM aL

Steel and Cast Iron

Carbon Steel 1 200

Carbon Manganese Steel 1 200

Alloy Steel 1 200

Case Hardened Steel 1 200

Nitrided Steel 1 200

Salt bath nitrocarburised 1 200

Stainless Steel(7-10 % Ni, 17-20 % Cr) 2 200

Sprayed Stainless Steel 1 200

Cast Iron(0.3 µm Ra) 1 200

Plated Steel with minimum thickness ofplating 0.013 mm

Cadmium 0.2 600

Hard Chrome 2.0 600

Lead 1.5 600

Nickel 0.2 600

Phosphated 0.2 300

Tin Nickel 1.2 600

Titanium Nitride 1.0 600

Tungsten CarbideFlame Plated 3.0 600

Zinc 0.2 600

Non ferrous metals

Aluminium Alloys 0.4 200

Bronze and Copper Base Alloys 0.1-0.4 200

Hard Anodised Aluminium (0.025 mm thick) 3.0 600

Material aM aL

16

3 Performance

Fig. 13: Bearing size factor aB

Bore BurnishingBurnishing or machining the bore of a DUbearing results in a reduction in the wearperformance. The application factor aC

given in Table 8 is used in the design cal-culations to allow for this effect.

Table 8: Bore burnishing or machining application factor aC

Type of Load

Fig. 14: Steady load, Bush stationary, Shaft rotating

Fig. 15: Rotating load, Shaft stationary, Bush rotating

Bea

ring

size

fact

or a

B

Shaft diameter DJ [mm]

0.2

0.3

1.0

1

0.5

0.1

0.4

5

0.60.7

0.90.8

2.0

6 7 8 9 10 50 100 500

1.5

Degree of sizingApplication factor

aC

Burnishing:Excess of burnishing tool diameter over mean bore size

0.025 mm 0.8

0.038 mm 0.6

0.050 mm 0.3

Boring: Depth of cut

0.025 mm 0.6

0.038 mm 0.3

0.050 mm 0.1

F2---

F2---

F F2---

F2---

F

17

3Performance

3.7 Calculation of Bearing Size In designing all bearings, the shaft diame-ter is usually determined by considerationsof physical stability or stiffness and themain variable to be determined is thelength of the bush or the land width of thethrust washer.The formulae given below enable desi-gners to calculate the length or width

necessary to satisfy both the Specific LoadLimit and the pU/Life relationship.If it is found that the total length exceedstwice the diameter of the shaft, this indica-tes that the conditions envisaged are toosevere for DU material and considerationshould be given to repositioning the bea-rings in order to reduce the load.

Calculation for BushesBush Stationary, Shaft Rotating

Bush Rotating, Shaft Stationary

Calculation for Thrust Washers

Calculation for Slideways

Fig. 16: Slideway

B F N LH aL+( )⋅ ⋅1 25 107 aT aM aB⋅⋅ ⋅ ⋅,--------------------------------------------------------------- F

plim Di⋅-------------------+=

(3.7.1) [mm]

1.25

B F N LH aL+( )⋅ ⋅2 5 107 aT aM aB⋅⋅ ⋅ ⋅,------------------------------------------------------------ F

plim Di⋅-------------------+=

(3.7.2) [mm]

2.5

Do Di–F N LH aL+( )⋅ ⋅

1 25, 107 aT aM aB⋅⋅ ⋅ ⋅--------------------------------------------------------------- Di

2 1 3 F,plim--------------++= Di–

(3.7.3) [mm]

1.251.3

A 238 F U LH aL+( )⋅ ⋅,103 aT aM⋅ ⋅

------------------------------------------------------ L LS+( )L

------------------ Fplim--------+⋅=

(3.7.4) [mm²]2.38

L

LS

W

DU/DUB Strip

Mating Surface

18

3 Performance

3.8 Calculation of Bearing Service LifeWhere the size of a bearing is governedlargely by the space available the followingcalculation can be used to determine whe-

ther its useful life will satisfy the require-ments. If the calculated life is inadequate,a larger bearing should be considered.

Specific load pBushes

Flanged Bushes

Thrust Washers

High load factor aE

If aE is negative then the bearing is over-loaded. Increase the bearing diameterand/or length.

Modified pU Factor Bushes

Flanged Bushes

Thrust Washers

For oscillating movement, calculate theaverage rotational speed.

Fig. 17: Oscillating cycle ϕ

p FDi B⋅---------------=

(3.8.1) [N/mm²]

p F0 04, Dfl

2 Di2–( )⋅

-----------------------------------------=

(3.8.2) [N/mm²]

0.04

p 4Fp Do

2 Di2–( )⋅

------------------------------=

(3.8.3) [N/mm²]

aEplim p–plim--------------=

(3.8.4) [–]

plim see Table 4, Page 13

pU 5 25 10 5–⋅, F N⋅aE B aT aM aB⋅⋅ ⋅ ⋅--------------------------------------------------=

(3.8.5) [N/mm² x m/s]

5.25

pU 6 5 10 4–⋅, F N⋅aE Dfl Di–( ) aT aM aB⋅⋅ ⋅ ⋅-------------------------------------------------------------------=

(3.8.6) [N/mm² x m/s]

6.5

pU 3 34 10 5–⋅, F N⋅aE Do Di–( ) aT aM aB⋅⋅ ⋅ ⋅-------------------------------------------------------------------=

(3.8.7) [N/mm² x m/s]

3.34

N 4ϕ Nosz⋅360

----------------------=

(3.8.8) [1/min]ϕ ϕ

123 4

19

3Performance

Estimation of bearing life LH Bushes (Steady load)

Bushes (Rotating load)

Flanged Bushes (Axial load)

Thrust Washers

Bore BurnishingIf the DU bush is bore burnished then thismust be allowed for in estimating the bea-

ring life by the application factor aC(Table 8, Page 16).

Estimated Bearing Life

SlidewaysSpecific load factor

If negative the bearing is overloaded andthe bearing area should be increased.

Speed temperature and materialapplication factors

Relative contact area factor

Estimated bearing life

Estimated bearing lives greater than4000 h are subject to error due to inaccu-racies in the extrapolation of test data.

For Oscillating Movements or Dynamicload: Calculate estimated number of cyclesZT.

ZT = LH x Nosz x 60 (for Oscillating Move-ments) (3.8.18).ZT = LH x C x 60 (for dynamic load)(3.8.19).Check that ZT is less than total number ofcycles Q for the operating specific load p(Table 4, Page 13).

If ZT <Q, LH will be limited by wear after ZTcycles.If ZT >Q, LH will be limited by fatigue afterZT cycles.

LH615pU---------- aL–=

(3.8.9) [h]

LH1230pU------------- aL–=

(3.8.10) [h]

LH410pU---------- aL–=

(3.8.11) [h]

LH410pU---------- aL–=

(3.8.12) [h]

LH LH aC⋅=

(3.8.13) [h]

aE1 A Fplim--------–=

(3.8.14) [–]

aE2420 aT aM⋅ ⋅

F U⋅---------------------------------=

(3.8.15) [–]

aE3AAM-------=

(3.8.16) [–]

LH aE1 aE2 aE3 aL–⋅ ⋅=

(3.8.17) [h]

20

3 Performance

3.9 Worked ExamplesCylindrical BushGiven:Load Details Steady Load Inside Diameter Di 40 mm

Continuous Rotation Length B 30 mmShaft Steel Bearing Load F 5000 N

Unlubricated at 25 °C Rotational Speed N 50 1/min

Calculation Constants and Application FactorsSpecific Load Limit plim 140 N/mm² (Table 4, Page 13)Temperature Application Factor aT 1.0 (Table 6, Page 14)Material Application Factor aM 1.0 (Table 7, Page 15)Bearing Size Factor aB 0.85 (Fig. 13, Page 16)Life Correction Constant aL 200 (Table 7, Page 15)

Calculation Ref ValueSpecific Load p [N/mm²]

(3.2.1), Page 12

Sliding Speed U [m/s]

(3.4.1), Page 13

pU Factor (Calculate from Table 5, Page 14)

(3.5.1), Page 14

High Load FactoraE [-] (must be >0)

(3.8.4), Page 18

Modified pU Factor [N/mm² x m/s]

(3.8.5), Page 18

LifeLH [h]

(3.8.9), Page 19

p FDi B⋅-------------- 5000

40 30⋅------------------ 4 17,= = = 4.17

U Di π N⋅ ⋅

60 103⋅----------------------- 40 3 14, 50⋅ ⋅

60 103⋅------------------------------------- 0 105,= = =0.1053.14

pU p U⋅ 4 17 0 105 0 438,=,⋅,= = 4.17 0.105 0.438

aEplim p–plim--------------- 140 4 17,–

140-------------------------- 0 97,= = =0.974.17

pU 5 25 10 5–⋅, F N⋅aE B aT aM aB⋅⋅ ⋅ ⋅------------------------------------------------- 0 53,= =5.25 0.53

LH615pU---------- aL– 615

0 53,-------------= 200 960=–= 0.53

Cylindrical BushGiven:Load Details Dynamic Load Inside Diameter Di 30 mm



Calculation Constants and Application FactorsSpecific Load Limit plim 60 N/mm² (Table 4, Page 13)Temperature Application Factor aT 1.0 (Table 6, Page 14)Material Application Factor aM 1.0 (Table 7, Page 15)Bearing Size Factor aB 1 (Fig. 13, Page 16)Life Correction Constant aL 200 (Table 7, Page 15)


(3.2.1), Page 12


(3.4.1), Page 13


(3.5.1), Page 14


(3.8.4), Page 18


(3.8.5), Page 18

LifeLH [h]

(3.8.9), Page 19

Calculate total load cycles

Table 4, Page 13

Q for 27.78 N/mm² = bearing will fatigue after 105

cycles (= 28 h)

p FDi B⋅-------------- 25000

30 30⋅------------------ 27 78,= = = 27.78

U Di π N⋅ ⋅

60 103⋅----------------------- 30 3 14, 15⋅ ⋅

60 103⋅------------------------------------- 0 024,= = =3.14 0.024

pU p U⋅ 27 87 0 024 0 669,=,⋅,= = 0.024 0.66927.78

aEplim p–plim--------------- 60 27 87,–

60-------------------------- 0 54,= = =27.78 0.54

pU 5 25 10 5–⋅, F N⋅aE B aT aM aB⋅⋅ ⋅ ⋅------------------------------------------------- 1 23,= =5.25 1.23

LH615pU---------- aL– 615

1 23,-------------= 200 350=–= 1.23

ZT 300 60 60⋅ ⋅ 300 106⋅= =

Cylindrical BushGiven:Load Details Steady Load

Load RotatingInside Diameter Di 50 mm





(3.2.1), Page 12


(3.4.1), Page 13


(3.5.1), Page 14


(3.8.4), Page 18


(3.8.5), Page 18

LifeLH [h]

(3.8.9), Page 19

p FDi B⋅-------------- 10000

50 50⋅------------------ 4 0,= = =4.0

U Di π N⋅ ⋅

60 103⋅----------------------- 50 3 14, 50⋅ ⋅

60 103⋅------------------------------------- 0 131,= = =0.1313.14

pU p U⋅ 4 0 0 131 0 524,=,⋅,= = 0.5420.1314.0

aEplim p–plim--------------- 60 4 0,–

60-------------------- 0 93,= = =4.0 0.93

pU 5 25 10 5–⋅, F N⋅aE B aT aM aB⋅⋅ ⋅ ⋅------------------------------------------------- 1 20,= = 1.205.25

LH1230pU------------- aL– 1230

1 2,-------------= 200 825=–= 1.20

Cylindrical BushGiven:Load Details Steady Load Inside Diameter Di 45 mm

Oscillating Movements Length B 40 mmShaft Stainless Steel Bearing Load F 40000 N

Unlubricated at 25 °C Frequency C 150Continuous operation Amplitudes ϕ 20 °



(3.2.1), Page 12


(3.4.1), Page 13

Average speedN [1/min]

(3.8.8), Page 18


(3.5.1), Page 14


(3.8.4), Page 18

Modified pU Factor[N/mm² x m/s]

(3.8.5), Page 18

LifeLH [h]

(3.8.9), Page 19

Calculate total load cycles

Table 4, Page 13

Q for 22.22 N/mm² = 108 bearing o.k.!

p FDi B⋅-------------- 40000

45 40⋅------------------ 22 22,= = = 22.22

U 45 3 14, 33 33,⋅ ⋅60 103⋅

----------------------------------------------- 0 078,= =3.14 33.33 0.078

N 4ϕ Nosz⋅360

---------------------- 4 20 150⋅ ⋅360

------------------------------ 33 33,= = = 33.33

pU p U⋅ 22 22 0 078 1 733,=,⋅,= =22.22 0.078 1.733

aEplim p–plim--------------- 140 22 22,–

140------------------------------ 0 84,= = =22.22 0.84

pU 5 25 10 5–⋅, F N⋅aE B aT aM aB⋅⋅ ⋅ ⋅------------------------------------------------- 1 29,= =5.25 1.29

LH615pU---------- aL– 615

1 29,-------------= 200 277=–=1.29

ZT 277 150 60⋅ ⋅ 2 5, 106⋅= = 2.5

21

3Performance

Thrust WasherGiven:Load Details Axial Load, Outside Diameter Do 62 mm

Continuous Rotation Inside Diameter Di 38 mmShaft Steel Bearing Load F 6500 N



Calculation Ref ValueSpecific Loadp [N/mm²]

(3.8.3), Page 18


(3.4.2), Page 13


(3.5.1), Page 14

High Load Factor aE [-]

(3.8.4), Page 18


(3.8.7), Page 18

Life LH [h]

(3.8.12), Page 19

p 4 6500⋅3 14, 622 382–( )⋅-------------------------------------------- 3 45,= =3.14

3.45

U62 38+( )

2--------------------- 3 14, 60⋅ ⋅

60 1000⋅---------------------------------------------------- 0 157,= =

3.140.157

pU p U⋅ 3 45 0 157 0 541,=,⋅,= = 3.45 0.157 0.541

aE140 3 45,–

140-------------------------- 0 98,= =3.45 0.98

pU 3 34, 10 5–⋅ 6500 60⋅0 87, 62 38–( ) 1 1 0 85,⋅⋅ ⋅ ⋅---------------------------------------------------------------------------- 0 65,= =3.340.87 0.85 0.650.87

LH410

0 65,------------- 200 431=–= 0.65

Flanged BushGiven:Load Details Axial Load Flange outside Diameter

Dfl

23 mm

Continuous Rotation Inside Diameter Di 15 mmShaft Steel Bearing Load F 250 N




(3.2.2), Page 12


(3.4.2), Page 13


(3.5.1), Page 14

High Load Factor aE [-]

(3.8.4), Page 18


(3.8.6), Page 18

Life LH [h]

(3.8.11), Page 19

p 2500 04, 232 152–( )⋅-------------------------------------------- 20 55,= =0.04

20.55

U23 15+( )

2--------------------- 3 14, 25⋅ ⋅

60 1000⋅---------------------------------------------------- 0 025,= =

3.140.025

pU p U⋅ 20 55 0 025 0 513,=,⋅,= = 20.55 0.025 0.513

aE140 20 55,–

140------------------------------ 0 85,= =20.55 0.85

pU 6 5, 10 5– 250⋅ 50⋅0 85, 23 15–( ) 1 1 1⋅⋅ ⋅ ⋅----------------------------------------------------------------- 0 59,= =6.50.85

0.59

LH410

0 59,------------- 200 495=–= 0.59

22

4 Data Sheet

4 Data Sheet4.1 Data for bearing design calculations

Quantity

Dimensions in mm

Inside Diameter Di

Length BOutside Diameter Do

Flange Diameter Dfl

Flange Thickness sfl

Length of slideplate LWidth of slideplate WThickness of slideplate sS

Radial load F [N]or specific load p [N/mm2]

Axial load F [N]or specific load p [N/mm2]

Oscillating frequency Nosz [1/min]

Rotational speed N [1/min]Speed U [m/s]Length of Stroke LS [mm]Frequency of Stroke [1/min]Oscillating cycle ϕ [°]

Continuous operation

Load

Service hours per day

Days per yearOperating timeIntermittent operation

Movement

Shaft DJBearing Housing DH

Fits and Tolerances

Ambient temperature Tamb [°]

Operating Environment

Non metal housing with poor heat transfer properties

Light pressing or insulated housing which poor heat transfer properties

Housing with good heat transferproperties

Material

Mating surface

Surface finish Ra [µm]Hardness HB/HRC

Process FluidLubricant

Alternate operation in water and dry

Dry

Lubrication

Process fluid lubrication

Continuous lubrication

Initial lubrication only

Hydrodynamic conditions

Dynamic viscosity η

Required service life LH [h]

Service life

Rotational movement Steady load Rotating load Oscillating movement

Cylindrical Bush Flanged Bush Thrust Washer Slideplate

Existing Design New Design

Special(Sketch)

Linear movement

B

Di (

Di,a

)

Do

Di (D

i,a)

Dfl

DiDo Do

Ws S

Bsfl sT

L

Customer DataCompany: City:Street: Post Code:

Project:Name:Tel.:

Date:Signature:Fax:

Application:

23

5Lubrication

5 LubricationAlthough DU was developed as a dry selflubricating bearing material, DU also provi-des excellent performance in lubricatedapplications.

The following sections describe the basicsof lubrication and provide guidance on theapplication of DU in such environments.

5.1 LubricantsDU can be used with most fluids including• water• lubricating oils• engine oil• turbine oil• hydraulic fluid• solvent• refrigerantsIn general, the fluid will be acceptable if itdoes not chemically attack the PTFE/leadoverlay or the porous bronze interlayer.Where there is doubt about the suitabilityof a fluid, a simple test is to submerge a

sample of DU material in the fluid for two tothree weeks at 15-20 °C above the opera-ting temperature. The following will usually indicate that thefluid is not suitable for use with DU:• A significant change in the thickness of

the DU material,• A visible change in the bearing surface

other than some discolouration or stain-ing

• A visible change in the microstructure ofthe bronze interlayer

5.2 TribologyThere are three modes of lubricated bea-ring operation which relate to the thicknessof the developed lubricant film between thebearing and the mating surface.These three modes of operation dependupon:

• Bearing dimensions• Clearance• Load• Speed• Lubricant Viscosity• Lubricant Flow

Hydrodynamic lubricationCharacterised by:• Complete separation of the shaft from

the bearing by the lubricant film• Very low friction and no wear of the bear-

ing or shaft since there is no contact.• Coefficients of friction of 0.001 to 0.01Hydrodynamic conditions occur when Fig. 18: Hydrodynamic lubrication

p U η⋅7·5------------ B

Di-----⋅≤

(5.2.1) [N/mm²]

24

5 Lubrication

Mixed film lubricationCharacterised by:• Combination of hydrodynamic and

boundary lubrication. • Part of the load is carried by localised

areas of self pressurised lubricant andthe remainder supported by boundarylubrication.

• Friction and wear depend upon thedegree of hydrodynamic support devel-oped.

• DU provides low friction and high wearresistance to support the boundary lubri-cated element of the load.

Fig. 19: Mixed film lubrication

Boundary lubrication Characterised by:• Rubbing of the shaft against the bearing

with virtually no lubricant separating thetwo surfaces.

• Bearing material selection is critical toperformance

• Shaft wear is likely due to contactbetween bearing and shaft.

• The excellent self lubricating propertiesof DU material minimises wear underthese conditions.

• The coefficient of friction with DU is typi-cally 0.02 to 0.06 under boundary lubri-cation conditions.

Fig. 20: Boundary lubrication

5.3 Characteristics of Lubricated DU bearingsDU is particularly effective in the mostdemanding of lubricated applications

where full hydrodynamic operation cannotbe maintained, for example:

• High load conditionsIn highly loaded applications operatingunder boundary or mixed film conditionsDU shows excellent wear resistance andlow friction.

• Start up and shut down under load With insufficient speed to generate ahydrodynamic film the bearing will oper-ate under boundary or mixed film condi-tions. DU minimises wear and requiresless start up torque than conventionalmetallic bearings.

• Sparse lubrication Many applications require the bearing tooperate with less than the ideal lubricantsupply, typically with splash or mist lubri-cation only. DU provides excellent selflubricating properties.

• Dry operation after running in waterIf a DU bearing is required to run dryafter running in water under non hydro-dynamic conditions then the wear resist-ance will be substantially reduced due toan increased amount of bedding in wear.

5.4 Design Guidance for Lubricated ApplicationsFig. 21 shows the three lubrication regimesdiscussed above. In order to use Fig. 21,using the formula on page 12 and page 13:• Calculate the specific load p,• Calculate the shaft surface speed U.

Using the viscosity temperature relati-onships presented in Table 9.• Determine the lubricant viscosity in

centipoise, of the lubricant.If the operating temperature of the fluid isunknown, a provisional temperature of25 °C above ambient can be used.

25

5Lubrication

Area 1The bearing will operate with boundarylubrication and pU factor will be the majordeterminant of bearing life. The DU bea-ring performance can be calculated using

the method given in Section 3, althoughthe result will probably underestimate thebearing life

Area 2The bearing will operate with mixed filmlubrication and the pU factor is no longer asignificant parameter in determining the

bearing life. The DU bearing performancewill depend upon the nature of the fluid andthe actual service conditions.

Area 3The bearing will operate with hydrodyna-mic lubrication. The bearing wear will bedetermined only by the cleanliness of the

lubricant and the frequency of start up andshut down.

Area 4These are the most demanding operatingconditions. The bearing is operated undereither high speed or high bearing load toviscosity ratio, or a combination of both. These conditions may cause:

• excessive operating temperature and/or • high wear rate.The bearing performance may be impro-ved by adding one or more grooves to thebearing and a shaft surface finish<0.05 µm Ra.

Fig. 21: Design guide for lubricated application

Table 9: Viscosity data

Spe

cific

bea

ring

load

p [N

/mm

²]

Journal surface speed U [m/s]

0.1

1.0

10

0.01 0.1 1.0 10

Increased clearances may be necessary

Detail bearing design may be necessary - consult the company

Area 1Effectively dry rubbing

Area 2Mixed film lubrication

Area 3Full hydrodynamic lubrication

Area 4

Vis

cosi

ty η

[cP]

Conditions:

- Steady unidirectional loading- Continuous, non reversing shaft rotation- Sufficient clearance between shaft and bearing- Sufficient lubricant flow

Viscosity cP

Temperature [°C] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Lubricant

ISO VG 32 310 146 77 44 27 18 13 9.3 7.0 5.5 4.4 3.6 3.0 2.5 2.2

ISO VG 46 570 247 121 67 40 25 17 12 9.0 6.9 5.4 4.4 3.6 3.0 2.6

ISO VG 68 940 395 190 102 59 37 24 17 12 9.3 7.2 5.8 4.7 3.9 3.3

ISO VG 100 2110 780 335 164 89 52 33 22 15 11.3 8.6 6.7 5.3 4.3 3.6

ISO VG 150 3600 1290 540 255 134 77 48 31 21 15 11 8.8 7.0 5.6 4.6

Diesel oil 4.6 4.0 3.4 3.0 2.6 2.3 2.0 1.7 1.4 1.1 0.95

Petrol 0.6 0.56 0.52 0.48 0.44 0.40 0.36 0.33 0.31

Kerosene 2.0 1.7 1.5 1.3 1.1 0.95 0.85 0.75 0.65 0.60 0.55

Water 1.79 1.30 1.0 0.84 0.69 0.55 0.48 0.41 0.34 0.32 0.28

26

5 Lubrication

5.5 Clearances for lubricated operationThe recommended shaft and housing dia-meters given for standard DU bushes willprovide sufficient clearance for applicati-ons operating with boundary lubrication.For bearings operating with mixed film orhydrodynamic lubrication it may be neces-

sary to improve the fluid flow through thebearing by reducing the recommendedshaft diameter by approximately 0.1 %,particularly when the shaft surface speedexceeds 2.5 m/s.

5.6 Mating Surface Finish for lubricated operation• Ra ≤0.4 µm Boundary lubrication• Ra = 0.1-0.2 µm Mixed film or hydrody-

namic conditions

• Ra ≤0.05 µm for the most demandingoperating conditions

5.7 Grooving for lubricated operationIn demanding applications an axial oilgroove will improve the performance ofDU. Fig. 22 shows the recommended formand location of a single groove with

respect to the applied load and the bearingsplit. GGB can manufacture special DUbearings with embossed or milled grooveson request.

Fig. 22: Location of oil holes and grooves

5.8 Grease LubricationDU is not generally recommended for usewith grease lubrication. In particular the fol-lowing must be avoided:• Dynamic loads - which can result in ero-

sion of the PTFE/lead bearing surface.

• Greases with EP additives or fillers suchas graphite or MoS2 which can causerapid wear of DU.

gap

20° -60°0° -45°

0.25-0.40

10-15 % of inside diameter of bearing0° -45°

Groove Detail Z

Z

F

27

6Bearing Assembly

6 Bearing AssemblyDimensions and TolerancesDU bushes are prefinished in the bore, andexcept in very exceptional circumstances,must not be burnished, broached or other-wise modified. It is essential that the cor-rect running clearance is used and thatboth the diameter of the shaft and the boreof the housing are finished to the limitsgiven in the tables. Under dry running con-ditions any increase in the clearancesgiven will result in a proportional reductionin performance.If the bearing housing is unusually flexiblethe bush will not close in by the calculated

amount and the running clearance will bemore than the optimum. In these circum-stances the housing should be boredslightly undersize or the journal diameterincreased, the correct size being determi-ned by experiment.Where free running is essential, or wherelight loads (less than 0.1 N/mm²) prevailand the available torque is low, increasedclearance is required and it is recommen-ded that the shaft size quoted in the tablebe reduced by 0.025 mm.

6.1 Allowance for Thermal ExpansionFor operation in high temperature environ-ments the clearance should be increasedby the amounts indicated by Fig. 23 to

compensate for the inward thermal expan-sion of the bearing lining.

Fig. 23: Increase in diametral clearanceIf the housing is non-ferrous then the boreshould be reduced by the amounts given inTable 10, in order to give an increased

interference fit to the bush, with a similarreduction in the journal diameter additionalto that indicated by Fig. 23.

Table 10: Allowance for high temperature

6.2 Tolerances for minimum clearanceWhere it is required to keep the variation ofassembled clearance to a minimum, closertolerances can be specified towards theupper end of the journal tolerance and thelower end of the housing tolerance.

If housings to H6 tolerance are used, thenthe journals should be finished to the follo-wing limits.The sizes in Table 11 give the followingnominal clearance range.

Table 11: Shaft tolarances for use with H6 housings

Table 12: Clearance vs bearing diameter

Incr

ease

in m

inim

um

diam

etra

l cle

aran

ce [m

m]

Environmental temperature Tamb [°C]

0.01

0.02

0 40 60 800

20 100 120 140

Housing material Reduction in housing diameter per 100 °C rise

Reduction in shaft diameter per100 °C rise

Aluminium alloys 0.1 % 0.1 % + values from Fig. 23

Copper base alloys 0.05 % 0.05 % + values from Fig. 23

Steel and cast iron – values from Fig. 23

Zinc base alloys 0.15 % 0.15 % + values from Fig. 23

Di DJ

<25 mm -0.019 to -0.029

>25 mm < 50 mm -0.021 to -0.035

Di CD

10 mm 0.005 to 0.078

50 mm 0.005 to 0.130

28

6 Bearing Assembly

Sizing

Fig. 24: Burnishing toolThe burnishing or fine boring of the bore ofan assembled DU bush in order to achievea smaller clearance tolerance is only per-missible if a substantial reduction in perfor-mance is acceptable. Fig. 24 shows arecommended burnishing tool for thesizing of DU bushes.

The coining section of the burnishing toolshould be case hardened (case depth 0.6-1.2 mm, HRC 60±2) and polished (RZ ≈1 µm).Note: Ball burnishing of DU bushes is notrecommended.

Table 13: Burnishing tool tolerances

The values given in Table 13 indicate thedimensions of the burnishing tool requiredto give specific increases in the bearingbore diameter.Exact values must be determined by test.The reduction in bearing performance as aresult of burnishing is allowed for in thebearing life calculation by the applicationfactor aC (Table 8, Page 16).

6.3 Counterface DesignThe suitability of mating surface materialsand recommendations of mating surfacefinish for use with DU are discussed indetail on page 15.DU is normally used in conjunction withferrous journals and thrust faces, but indamp or corrosive surroundings, particu-larly without the protection of oil or grease,stainless steel, hard chromium plated mildsteel, or hard anodised aluminium isrecommended. When plated mating sur-faces are specified the plating should pos-sess adequate strength and adhesion,particularly if the bearing is to operate withhigh fluctuating loads.The shaft or thrust collar used in con-junction with the DU bush or thrust washermust extend beyond the bearing surface inorder to avoid cutting into it. The matingsurface must also be free from grooves orflats, the end of the shaft should be given alead-in chamfer and all sharp edges orprojections which may damage the softoverlay of the DU must be removed. Fig. 25: Counterface Design

0.5°

6±2

Di

B +1

0B

DC

R 1.5

Assembled bush

Inside-∅

Required bush

Inside-∅

Required burnishing

tool diameter DC

Di,a Di,a + 0.025 Di,a + 0.06

Di,a Di,a + 0.038 Di,a + 0.08

Di,a Di,a + 0.050 Di,a + 0.1

incorrect correct

29

6Bearing Assembly

6.4 Installation

Fitting of cylindrical bushes

Fig. 26: Fitting of cylindrical bushes

Fitting of flanged bushes

Fig. 27: Fitting of flanged bushes

Insertion Forces

Fig. 28: Maximum Insertion Force

Do <55 mm Do >55 mm Do >120 mm

15° -30°

Mounting Ring

Note:Lightly oil back of bush to assist assembly.

for D

H ≤

125

= 0.

8fo

r DH

> 1

25 =

2

for D

H ≤

125

= 0.

8fo

r DH

> 1

25 =

2Di

Di

DH

DH

cham

fer m

in =

r m

ax x

45°

Z

Z

0.5

x 15

°

r max see pages 38/44

Max

imum

inse

rtion

forc

e [N

/mm

uni

t len

gth]

Bush bore diameter Di [mm]

200

400

1000

0 30 40 50

800

0

20 100

600

10

30

6 Bearing Assembly

AlignmentAccurate alignment is an important consi-deration for all bearing assemblies, but isparticularly so for dry bearings becausethere is no lubricant to spread the load.

With DU bearings misalignment over thelength of a bush (or pair of bushes), or overthe diameter of a thrust washer should notexceed 0.020 mm as illustrated in Fig. 29.

Fig. 29: Alignment

SealingWhile DU can tolerate the ingress of somecontaminant materials into the bearing wit-hout loss of performance, where there isthe possibility of highly abrasive material

entering the bearing, a suitable sealingarrangement, as illustrated in Fig. 30should be provided.

Fig. 30: Recommended sealing arrangements

6.5 Axial LocationWhere axial location is necessary, it isadvisable to fit DU thrust washers in con-

junction with DU bushes, even when theaxial loads are low.

Fitting of Thrust WashersDU thrust washers should be located in arecess as shown in Fig. 31. The recessdiameter should be 0.125 mm larger thenthe washer diameter and the depth asgiven in the product tables.

If a recess is not possible one of the follo-wing methods may be used:• Two dowel pins• Two screws• Adhesive• Soldering

31

6Bearing Assembly

Important Note• Ensure the washer ID does not touch the

shaft after assembly• Ensure that the washer is mounted with

the steel backing to the housing• Dowels pins should be recessed

0.25 mm below the bearing surface• Screws should be countersunk 0.25 mm

below the bearing surface• DU must not be heated above 320 °C• Contact adhesive manufacturers for

guidance selection of suitable adhesives• Protect the bearing surface to prevent

contact with adhesive

Fig. 31: Installation of Thrust-Washer

Grooves for Wear Debris RemovalTests with thrust washers have demonstra-ted that for optimum dry wear performanceat specific loads in excess of 35 N/mm2,four wear debris removal grooves should

be machined in the bearing surface asshown in Fig. 32. Grooves in bushes have not been found tobe beneficial in this respect.

Fig. 32: Debris removal Grooves

SlidewaysDU strip material for use as slideway bea-rings should be installed using one of thefollowing methods:

• Countersunk screws• Adhesives• Mechanical location as shown in Fig. 33

Fig. 33: Mechanical location of DU slideplates

0.1 x Di 0.4 deep

32

7 Modification

7 Modification7.1 Cutting and MachiningThe modification of DU bearing compon-ents requires no special procedures. Ingeneral it is more satisfactory to performmachining or drilling operations from thePTFE side in order to avoid burrs. Whencutting is done from the steel side, the

minimum cutting pressure should be usedand care taken to ensure that any steel orbronze particles protruding into the remai-ning bearing material, and all burrs, areremoved.

Drilling Oil HolesBushes should be adequately supportedduring the drilling operation to ensure that

no distortion is caused by the drilling pres-sure.

Cutting Strip MaterialDU strip material may be cut to size by anyone of the following methods. Care must be taken to protect the bearingsurface from damage and to ensure thatno deformation of the strip occurs:• Using side and face cutter, or slitting

saw, with the strip held flat and securely

on a horizontal milling machine.• Cropping• Guillotine

(For widths less than 90 mm only)• Water-jet cutting• Laser cutting (see Health Warning)

7.2 Electroplating

DU ComponentsIn order to provide some protection inmildly corrosive environments the steelback and end faces of standard range DUbearings are tin flashed. If exposed to corrosive liquids further pro-tection should be provided and in very cor-rosive conditions DUB should beconsidered.DU can be electroplated with most of theconventional electroplating metals inclu-ding the following:• zinc ISO 2081-2• cadmium ISO 2081-2• nickel ISO 1456-8• hard chromium ISO 1456-8

For the harder materials if the specifiedplating thickness exceeds approximately 5µm then the housing diameter should beincreased by twice the plating thickness inorder to maintain the correct assembledbearing bore size.With light deposits of materials such ascadmium, no special precautions arenecessary. Harder materials such as nickelhowever, may strike through the PTFE/lead surface layer of DU and it is advisableto use an appropriate method of maskingthe bearing surface.Where electrolytic attack is possible testsshould be conducted to ensure that all thematerials in the bearing environment aremutually compatible.

Mating SurfacesDU can be used against some platedmaterials as indicated on page 15.

Care should be taken to ensure that therecommended shaft sizes and surfacefinish are achieved after the plating pro-cess.

33

8Standard Products

8 Standard Products8.1 DU Cylindrical Bushes

All dimensions in mm

0.3

min

.

s 3D

i(D

i,a)

Do

Co

Ci

B

Z

20° ±8°

Detail Z

Split

Dimensions and Tolerances according to ISO 3547 and GSP-Specifications

Part No.Nominal Diameter Wall thichness

s3

WidthB

Shaft-∅DJ [h6, f7, h8]

Housing−∅DH [H6, H7]

Bush-∅ Di,aAss. in H6/H7

housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

0203DU2 3.5

0.7500.730

3.252.75

h6

2.0001.994

H6

3.5083.500

2.0482.000

0.0540.000

0205DU 5.254.75

0303DU

3 4.5

3.252.75

3.0002.994

4.5084.500

3.0483.0000305DU 5.25

4.75

0306DU 6.255.75

0403DU

4 5.5

3.252.75

4.0003.992

5.5085.500

4.0484.000

0.0560.000

0404DU 4.253.75

0406DU 6.255.75

0410DU 10.259.75

0505DU

5 7

1.0050.980

5.254.75

f7

4.9904.978

H7

7.0157.000

5.0554.990

0.0770.000

0508DU 8.257.75

0510DU 10.259.75

0604DU

6 8

4.253.75

5.9905.978

8.0158.000

6.0555.990

0606DU 6.255.75

0608DU 8.257.75

0610DU 10.259.75

0705DU7 9

5.254.75 6.987

6.9729.0159.000

7.0556.990

0.0830.0030710DU 10.25

9.75

Outside Co and Inside Ci chamfers

a = Chamfer Co machined or rolled at the opinion of the manufacturer

b = Ci can be a radius or a chamfer in accordance with ISO 13715

Wall thickness s3

Co (a)Ci (b)

machined rolled0.75 0.5 ± 0.3 0.5 ± 0.3 -0.1 to -0.4

1 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.51.5 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.7

Wall thickness s3

Co (a)Ci (b)

machined rolled2 1.2 ± 0.4 1.0 ± 0.4 -0.1 to -0.7

2.5 1.8 ± 0.6 1.2 ± 0.4 -0.2 to -1.0

34

8 Standard Products

0806DU

8 10

1.0050.980

6.255.75

f7

7.9877.972

H7

10.01510.000

8.0557.990

0.0830.003

0808DU 8.257.75

0810DU 10.259.75

0812DU 12.2511.75

1006DU

10 12

6.255.75

9.9879.972

12.01812.000

10.0589.990

0.0860.003

1008DU 8.257.75

1010DU 10.259.75

1012DU 12.2511.75

1015DU 15.2514.75

1020DU 20.2519.75

1208DU

12 14

8.257.75

11.98411.966

14.01814.000

12.05811.990

0.0920.006

1210DU 10.259.75

1212DU 12.2511.75

1215DU 15.2514.75

1220DU 20.2519.75

1225DU 25.2524.75

1310DU13 15

10.259.75 12.984

12.96615.01815.000

13.05812.9901320DU 20.25

19.75

1405DU

14 16

5.254.75

13.98413.966

16.01816.000

14.05813.990

1410DU 10.259.75

1412DU 12.2511.75

1415DU 15.2514.75

1420DU 20.2519.75

1425DU 25.2524.75

1510DU

15 17

10.259.75

14.98414.966

17.01817.000

15.05814.990

1512DU 12.2511.75

1515DU 15.2514.75

1520DU 20.2519.75

1525DU 25.2524.75

1610DU

16 18

10.259.75

15.98415.966

18.01818.000

16.05815.990

1612DU 12.2511.75

1615DU 15.2514.75

1620DU 20.2519.75

1625DU 25.2524.75

1720DU 17 19 20.2519.75

16.98416.966

19.02119.000

17.06116.990

0.0950.006


s3

WidthB




housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

35

8Standard Products

1810DU

18 20 1.0050.980

10.259.75

f7

17.98417.966

H7

20.02120.000

18.06117.990

0.0950.006

1815DU 15.2514.75

1820DU 20.2519.75

1825DU 25.2524.75

2010DU

20 23

1.5051.475

10.259.75

19.98019.959

23.02123.000

20.07119.990

0.1120.010

2015DU 15.2514.75

2020DU 20.2519.75

2025DU 25.2524.75

2030DU 30.2529.75

2215DU

22 25

15.2514.75

21.98021.959

25.02125.000

22.07121.990

2220DU 20.2519.75

2225DU 25.2524.75

2230DU 30.2529.75

2415DU

24 27

15.2514.75

23.98023.959

27.02127.000

24.07123.990

2420DU 20.2519.75

2425DU 25.2524.75

2430DU 30.2529.75

2515DU

25 28

15.2514.75

24.98024.959

28.02128.000

25.07124.990

2520DU 20.2519.75

2525DU 25.2524.75

2530DU 30.2529.75

2550DU 50.2549.75

2815DU

28 32

2.0051.970

15.2514.75

27.98027.959

32.02532.000

28.08527.990

0.1260.010

2820DU 20.2519.75

2825DU 25.2524.75

2830DU 30.2529.75

3010DU

30 34

10.259.75

29.98029.959

34.02534.000

30.08529.990

3015DU 15.2514.75

3020DU 20.2519.75

3025DU 25.2524.75

3030DU 30.2529.75

3040DU 40.2539.75

3220DU

32 36

20.2519.75

31.97531.950

36.02536.000

32.08531.990

0.1350.0153230DU 30.25

29.75

3240DU 40.2539.75


s3

WidthB




housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

36

8 Standard Products

3520DU

35 39

2.0051.970

20.2519.75

f7

34.97534.950

H7

39.02539.000

35.08534.990

0.1350.015

3530DU 30.2529.75

3535DU 35.2534.75

3540DU 40.2539.75

3550DU 50.2549.75

3720DU 37 41 20.2519.75

36.97536.950

41.02541.000

37.08536.990

4020DU

40 44

20.2519.75

39.97539.950

44.02544.000

40.08539.990

4030DU 30.2529.75

4040DU 40.2539.75

4050DU 50.2549.75

4520DU

45 50

2.5052.460

20.2519.75

44.97544.950

50.02550.000

45.10544.990

0.1550.015

4530DU 30.2529.75

4540DU 40.2539.75

4545DU 45.2544.75

4550DU 50.2549.75

5020DU

50 55

20.2519.75

49.97549.950

55.03055.000

50.11049.990

0.1600.015

5030DU 30.2529.75

5040DU 40.2539.75

5050DU 50.2549.75

5060DU 60.2559.75

5520DU

55 60

20.2519.75

54.97054.940

60.03060.000

55.11054.990

0.1700.020

5525DU 25.2524.75

5530DU 30.2529.75

5540DU 40.2539.75

5550DU 50.2549.75

5555DU 55.2554.75

5560DU 60.2559.75

6020DU

60 65 2.5052.460

20.2519.75

59.97059.940

65.03065.000

60.11059.990

0.1700.020

6030DU 30.2529.75

6040DU 40.2539.75

6050DU 50.2549.75

6060DU 60.2559.75

6070DU 70.2569.75


s3

WidthB




housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

37

8Standard Products

6530DU

65 70

2.5052.460

30.2529.75

f7

64.97064.940

H7

70.03070.000

65.11064.990

0.1700.020

6550DU 50.2549.75

6570DU 70.2569.75

7040DU

70 75

40.2539.75

69.97069.940

75.03075.000

70.11069.9907050DU 50.25

49.75

7070DU 70.2569.75

7560DU75 80

60.2559.75 74.970

74.94080.03080.000

75.11074.9907580DU 80.25

79.75

8040DU

80 85

2.4902.440

40.5039.50

h8

80.00079.946

85.03585.000

80.15580.020

0.2090.020

8060DU 60.5059.50

8080DU 80.5079.50

80100DU 100.5099.50

8530DU

85 90

30.5029.50

85.00084.946

90.03590.000

85.15585.0208560DU 60.50

59.50

85100DU 100.5099.50

9060DU90 95

60.5059.50 90.000

89.94695.03595.000

90.15590.02090100DU 100.50

99.50

9560DU95 100

60.5059.50 95.000

94.946100.035100.000

95.15595.02095100DU 100.50

99.50

10050DU

100 105

50.5049.50

100.00099.946

105.035105.000

100.155100.02010060DU 60.50

59.50

100115DU 115.50114.50

10560DU105 110

60.5059.50 105.000

104.946110.035110.000

105.155105.020105115DU 115.50

114.50

11060DU110 115

60.5059.50 110.000

109.946115.035115.000

110.155110.020110115DU 115.50

114.50

11550DU115 120

50.5049.50 115.000

114.946120.035120.000

115.155115.02011570DU 70.50

69.50

12050DU

120 125

2.4652.415

50.5049.50

120.000119.946

125.040125.000

120.210120.070

0.2640.07012060DU 60.50

59.50

120100DU 100.5099.50

125100DU 125 130 100.5099.50

125.000124.937

130.040130.000

125.210125.070

0.2730.07013060DU

130 135

60.5059.50 130.000

129.937135.040135.000

130.210130.070130100DU 100.50

99.50


s3

WidthB




housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

38

8 Standard Products

8.2 DU Flanged Bushes


13560DU135 140

2.4652.415

60.5059.50

h8

135.000134.937

H7

140.040140.000

135.210135.070

0.2730.070

13580DU 80.5079.50

14060DU140 145

60.5059.50 140.000

139.937145.040145.000

140.210140.070140100DU 100.50

99.50

15060DU

150 155

60.5059.50

150.000149.937

155.040155.000

150.210150.07015080DU 80.50

79.50

150100DU 100.5099.50

16080DU160 165

80.5079.50 160.000

159.937165.040165.000

160.210160.070160100DU 100.50

99.50

180100DU 180 185

100.5099.50

180.000179.937

185.046185.000

180.216180.070

0.2790.070

200100DU 200 205 200.000199.928

205.046205.000

200.216200.070

0.2880.070210100DU 210 215 210.000

209.928215.046215.000

210.216210.070

220100DU 220 225 220.000219.928

225.046225.000

220.216220.070

250100DU 250 255 250.000249.928

255.052255.000

250.222250.070

0.2940.070

300100DU 300 305 300.000299.919

305.052305.000

300.222300.070

0.3030.070


s3

WidthB




housing

ClearanceCD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

D

i(D

i,a)

Do

rmax

0.3

min

.

Dfl

Co

Ci

B

20° ±8°

Z

sfl

Do - Di

2

s 3

Detail Z

Split


Part No.

Nominal Diameter

Wall thickness

s3

Flange thickness

sfl

Flange-∅ Dfl

WidthB

Shaft-∅DJ [h6, f7]



housing

Clearance CD

Di Domaxmin.

max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

max. min.

BB0304DU 3 4.5 0.7500.730

0.800.70

7.506.50 4.25

3.75 h6

3.0002.994 H6

4.5084.500

3.0483.000

0.0540.000

BB0404DU 4 5.5 9.508.50

4.0003.992

5.5084.500

4.0484.000

0.0560.000

BB0505DU 5 7 1.0050.980

1.050.80

10.509.50

5.254.75 f7 4.990

4.978 H7 7.0157.000

5.0554.990

0.0770.000




Wall thickness s3

Co (a)Ci (b)


1 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.51.5 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.7

Wall thickness s3

Co (a)Ci (b)


2.5 1.8 ± 0.6 1.2 ± 0.4 -0.2 to -1.0

39

8Standard Products

BB0604DU6 8

1.0050.980

1.050.80

12.5011.50

4.253.75

f7

5.9905.978

H7

8.0158.000

6.0555.990

0.0770.000BB0608DU 8.25

7.75

BB0806DU

8 10 15.5014.50

5.755.25

7.9877.972

10.01510.000

8.0557.990

0.0830.003BB0808DU 7.75

7.25

BB0810DU 9.759.25

BB1007DU

10 12 18.5017.50

7.256.75

9.9879.972

12.01812.000

10.0589.990

0.0860.003

BB1009DU 9.258.75

BB1012DU 12.2511.75

BB1017DU 17.2516.75

BB1207DU

12 14 20.5019.50

7.256.75

11.98411.966

14.01814.000

12.05811.990

0.0920.006

BB1209DU 9.258.75

BB1212DU 12.2511.75

BB1217DU 17.2516.75

BB1412DU14 16 22.50

21.50

12.2511.75 13.984

13.96616.01816.000

14.05813.990BB1417DU 17.25

16.75

BB1509DU

15 17 23.5022.50

9.258.75

14.98414.966

17.01817.000

15.05814.990BB1512DU 12.25

11.75

BB1517DU 17.2516.75

BB1612DU16 18 24.50

23.50

12.2511.75 15.984

15.96618.01818.000

16.05815.990BB1617DU 17.25

16.75

BB1812DU

18 20 26.5025.50

12.2511.75

17.98417.966

20.02120.000

18.06117.990

0.0950.006BB1817DU 17.25

16.75

BB1822DU 22.2521.75

BB2012DU

20 23

1.5051.475

1.601.30

30.5029.50

11.7511.25

19.98019.959

23.02123.000

20.07119.990

0.1120.010

BB2017DU 16.7516.25

BB2022DU 21.7521.25

BB2512DU

25 28 35.5034.50

11.7511.25

24.98024.959

28.02128.000

25.07124.990BB2517DU 16.75

16.25

BB2522DU 21.7521.25

BB3016DU30 34

2.0051.970

2.101.80

42.5041.50

16.2515.75 29.980

29.95934.02534.000

30.08529.990

0.1260.010BB3026DU 26.25

25.75

BB3516DU35 39 47.50

46.50

16.2515.75 34.975

34.95039.02539.000

35.08534.990

0.1350.015

BB3526DU 26.2525.75

BB4016DU40 44 53.50

52.50

16.2515.75 39.975

39.95044.02544.000

40.08539.990BB4026DU 26.25

25.75

BB4516DU45 50 2.505

2.4602.602.30

58.5057.50

16.2515.75 44.975

44.95050.02550.000

45.10544.990

0.1550.015BB4526DU 26.25

25.75

Part No.

Nominal Diameter

Wall thickness

s3

Flange thickness

sfl

Flange-∅ Dfl

WidthB

Shaft-∅DJ [h6, f7]



housing

Clearance CD

Di Domaxmin.

max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

max. min.

40

8 Standard Products

8.3 DU Flanged Washers


Corrosion Protection: Washers will be supplied covered with a light coating of oil.Tab (Lug) Form: Washers are supplied with this feature in an unformed state (Flat). This feature may be supplied in the formedstate only when requested by the customer.

r 1.25

Do

d p

4.8 -0.6

Di

Dfl

1.5 x 45°

r 1

8±1

5 ±0.1

30°

2.00 +0/-0.05

Part No.

Inside-∅Di

Outside-∅Do

Flange-∅Dfl

Location-∅dP

max.min.

max.min.

max.min.

max.min.

BS40DU 40.740.2

75.074.5

44.00043.900

65.064.5

BS50DU 51.551.0

85.084.5

55.00054.880

75.074.5

BS60DU 61.561.0

95.094.5

65.00064.880

85.084.5

BS70DU 71.571.0

110.0109.5

75.00074.880

100.099.5

BS80DU 81.581.0

120.0119.5

85.00084.860

110.0109.5

BS90DU 91.591.0

130.0129.5

95.00094.860

120.0119.5

BS100DU 101.5101.0

140.0139.5

105.000104.860

130.0129.5

41

8Standard Products

8.4 DU Thrust Washer


dP

Di

Do

sT

Ha

Do

d p

dD

Hd

[D10

]

DJ

Part No.

Inside-∅Di

Outside-∅Do

Thickness sTDowel Hole Recess Depth

Ha∅ dD PCD-∅ dP

min. max. max. min. max.min.

max.min.

max.min.

max.min.

WC08DU 10.00 10.25 20.00 19.75

1.501.45

No Hole No Hole

1.200.95

WC10DU 12.00 12.25 24.00 23.75 1.8751.625

18.1217.88

WC12DU 14.00 14.25 26.00 25.75

2.3752.125

20.1219.88

WC14DU 16.00 16.25 30.00 29.75 22.1221.88

WC16DU 18.00 18.25 32.00 31.75 25.1224.88

WC18DU 20.00 20.25 36.00 35.75

3.3753.125

28.1227.88

WC20DU 22.00 22.25 38.00 37.75 30.1229.88

WC22DU 24.00 24.25 42.00 41.75 33.1232.88

WC24DU 26.00 26.25 44.00 43.75 35.1234.88

WC25DU 28.00 28.25 48.00 47.75

4.3754.125

38.1237.88

WC30DU 32.00 32.25 54.00 53.75 43.1242.88

WC35DU 38.00 38.25 62.00 61.75 50.1249.88

WC40DU 42.00 42.25 66.00 65.75 54.1253.88

WC45DU 48.00 48.25 74.00 73.75

2.001.95

61.1260.88

1.701.45WC50DU 52.00 52.25 78.00 77.75 65.12

64.88

WC60DU 62.00 62.25 90.00 89.75 76.1275.88

42

8 Standard Products

8.5 DUB Cylindrical Bushes


0.3

min

.

s 3D

i(D

i,a)

Do

Co

Ci

B

Z

20° ±8°

Detail Z

Split


Part No.

Nominal Diameter

Wall thickness s3

WidthB



Bush-∅ Di,aass. in H6/H7

housing

Clearance CD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

0203DUB2 3.5

0.7500.730

3.252.75

h6

2.0001.994

H6

3.5083.500

2.0482.000 0.054

0.0000205DUB 5.254.75

0306DUB 3 4.5 6.255.75

3.0002.994

4.5084.500

3.0483.000

0404DUB4 5.5

4.253.75 4.000

3.9925.5085.500

4.0484.000

0.0560.0000406DUB 6.25

5.75

0505DUB5 7

1.0050.980

5.254.75

f7

4.9904.978

H7

7.0157.000

5.0554.990

0.0770.000

0510DUB 10.259.75

0606DUB

6 8

6.255.75

5.9905.978

8.0158.000

6.0555.9900608DUB 8.25

7.75

0610DUB 10.259.75

0808DUB

8 10

8.257.75

7.9877.972

10.01510.000

8.0557.990

0.0830.0030810DUB 10.25

9.75

0812DUB 12.2511.75

1010DUB10 12

10.259.75 9.987

9.97212.01812.000

10.0589.990

0.0860.0031015DUB 15.25

14.75

1208DUB

12 14

8.257.75

11.98411.966

14.01814.000

12.05811.990

0.0920.006

1210DUB 10.259.75

1212DUB 12.2511.75

1215DUB 15.2514.75




Wall thickness s3

Co (a)Ci (b)


1 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.51.5 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.7

Wall thickness s3

Co (a)Ci (b)


2.5 1.8 ± 0.6 1.2 ± 0.4 -0.2 to -1.0

43

8Standard Products

1410DUB

14 16

1.0050.980

10.259.75

f7

13.98413.966

H7

16.01816.000

14.05813.990

0.0920.006

1415DUB 15.2514.75

1420DUB 20.2519.75

1515DUB15 17

15.2514.75 14.984

14.96617.01817.000

15.05814.9901525DUB 25.25

24.75

1615DUB16 18

15.2514.75 15.984

15.96618.01818.000

16.05815.9901625DUB 25.25

24.75

1820DUB18 20

20.2519.75 17.984

17.96620.02120.000

18.06117.990

0.0950.0061825DUB 25.25

24.75

2015DUB

20 23

1.5051.475

15.2514.75

19.98019.959

23.02123.000

20.07119.990

0.1120.010

2020DUB 20.2519.75

2025DUB 25.2524.75

2030DUB 30.2529.75

2215DUB

22 25

15.2514.75

21.98021.959

25.02125.000

22.07121.9902220DUB 20.25

19.75

2225DUB 25.2524.75

2515DUB25 28

15.2514.75 24.980

24.95928.02128.000

25.07124.9902525DUB 25.25

24.75

2830DUB 28 32

2.0051.970

30.2529.75

27.98027.959

32.02532.000

28.08527.990

0.1260.010

3020DUB

30 34

20.2519.75

29.98029.959

34.02534.000

30.08529.9903030DUB 30.25

29.75

3040DUB 40.2539.75

3520DUB35 39

20.2519.75 34.975

34.95039.02539.000

35.08534.990

0.1350.015

3530DUB 30.2529.75

4030DUB40 44

30.2529.75 39.975

39.95044.02544.000

40.08539.9904050DUB 50.25

49.75

4530DUB45 50

2.5052.460

30.2529.75 44.975

44.95050.02550.000

45.10544.990

0.1550.0154550DUB 50.25

49.75

5040DUB50 55

40.2539.75 49.975

49.95055.03055.000

50.11049.990

0.1600.0155060DUB 60.25

59.75

5540DUB 55 60 40.2539.75

54.97054.940

60.03060.000

55.11054.990

0.1700.020

6040DUB

60 65

40.2539.75

59.97059.940

65.03065.000

60.11059.990

6050DUB 50.2549.75

6060DUB 60.2559.75

6070DUB 70.2569.75

6570DUB 65 70 70.2569.75

64.97064.940

70.03070.000

65.11064.990

Part No.

Nominal Diameter

Wall thickness s3

WidthB




housing

Clearance CD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

44

8 Standard Products

8.6 DUB Flanged Bushes


7050DUB70 75 2.505

2.460

50.2549.75

f7

69.97069.940

H7

75.03075.000

70.11069.990 0.170

0.0207070DUB 70.2569.75

7580DUB 75 80 80.2579.75

74.97074.940

80.03080.000

75.11074.990

8060DUB80 85

2.4902.440

60.5059.50

h8

80.00079.946

85.03585.000

80.15580.020

0.2010.02080100DUB 100.50

99.50

85100DUB 85 90 100.5099.50

85.00084.946

90.03590.000

85.15585.020

0.2090.020

9060DUB90 95

60.5059.50 90.000

89.94695.03595.000

90.15590.02090100DUB 100.50

99.50

95100DUB 95 100 100.5099.50

95.00094.946

100.035100.000

95.15595.020

10060DUB100 105

60.5059.50 100.000

99.946105.035105.000

100.155100.020100115DUB 115.50

114.50

105115DUB 105 110 115.50114.50

105.000104.946

110.035110.000

105.155105.020

110115DUB 110 115 115.50114.50

110.000109.946

115.035115.000

115.155115.020

Part No.

Nominal Diameter

Wall thickness s3

WidthB




housing

Clearance CD

Di Domax.min.

max.min.

max.min.

max.min.

max.min.

max.min.

D

i(D

i,a)

Do

rmax

0.3

min

.

Dfl

Co

Ci

B

20° ±8°

Z

sfl

Do - Di

2

s 3

Detail Z

Split


Part No.

Nominal Diameter

Wall thickness

s3

Flange thickness

sfl

Flange-∅ Dfl

Width B



Bush-∅ Di,a Ass. in H6/H7 housing

Clearance CD

Di Domaxmin.

max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

max. min.

BB0304DUB 3 4.5 0.7500.730

0.800.70

7.506.50 4.25

3.75 h6

3.0002.994 H6

4.5084.500

3.0483.000

0.0540.000

BB0404DUB 4 5.5 9.508.50

4.0003.992

5.5084.500

4.0484.000

0.0560.000

BB0505DUB 5 7 1.0050.980

1.050.80

10.509.50

5.254.75 f7 4.990

4.978 H7 7.0157.000

5.0554.990

0.0770.000




Wall thickness s3

Co (a)Ci (b)


1 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.51.5 0.6 ± 0.4 0.6 ± 0.4 -0.1 to -0.7

Wall thickness s3

Co (a)Ci (b)


2.5 1.8 ± 0.6 1.2 ± 0.4 -0.2 to -1.0

45

8Standard Products

BB0604DUB6 8

1.0050.980

1.050.80

12.5011.50

4.253.75

f7

5.9905.978

H7

8.0158.000

6.0555.990

0.0770.000BB0608DUB 8.25

7.75

BB0806DUB8 10 15.50

14.50

5.755.25 7.987

7.97210.01510.000

8.0557.990

0.0830.000BB0810DUB 9.75

9.25

BB1007DUB10 12 18.50

17.50

7.256.75 9.987

9.97212.01812.000

10.0589.990

0.0860.003BB1012DUB 12.25

11.75

BB1207DUB

12 14 20.5019.50

7.256.75

11.98411.966

14.01814.000

12.05811.990

0.0920.006

BB1209DUB 9.258.75

BB1212DUB 12.2511.75

BB1417DUB 14 16 22.5021.50

17.2516.75

13.98413.966

16.01816.000

14.0513.990

BB1512DUB15 17 23.50

22.50

12.2511.75 14.984

14.96617.01817.000

15.05814.990BB1517DUB 17.25

16.75

BB1612DUB16 18 24.50

23.50

12.2511.75 15.984

15.96618.01818.000

16.05815.990BB1617DUB 17.25

16.75

BB1812DUB18 20 26.50

25.50

12.2511.75 17.984

17.96620.02120.000

18.06117.990

0.0950.006BB1822DUB 22.25

21.75

BB2012DUB20 23

1.5051.475

1.601.30

30.5029.50

11.7511.25 19.980

19.95923.02123.000

20.07119.990

0.1120.010

BB2017DUB 16.7516.25

BB2512DUB25 28 35.50

34.50

11.7511.25 24.980

24.95928.02128.000

25.07124.990BB2522DUB 21.75

21.25

BB3016DUB30 34

2.0051.970

2.101.80

42.5041.50

16.2515.75 29.980

29.95934.02534.000

30.08529.990

0.1260.010BB3026DUB 26.25

25.75

BB3526DUB 35 39 47.5046.50

26.2525.75

34.97534.950

39.02539.000

35.08534.990

0.1350.015

BB4026DUB 40 44 53.5052.50

26.2525.75

39.97539.950

44.02544.000

40.08539.990

0.1350.015

BB4526DUB 45 50 2.5052.460

2.602.30

58.5057.50

26.2525.75

44.97544.950

50.02550.000

45.10544.990

0.1550.015

Part No.

Nominal Diameter

Wall thickness

s3

Flange thickness

sfl

Flange-∅ Dfl

Width B



Bush-∅ Di,a Ass. in H6/H7 housing

Clearance CD

Di Domaxmin.

max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

max. min.

46

8 Standard Products

8.7 DU Cylindrical Bushes - Inch sizes

All dimensions in inch

Ci

Co

.012

min

.

α

β

Di

Do

(Di,a

)s 3

B

ZDetail Z

Split

Part No.Nominal Diameter Wall thickness

s3

WidthB

Shaft-∅DJ

Housing-∅DH

Bush-∅ Di,aAss. in DH housing

Clearance CD

Di Do B max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

02DU021/8 3/16

1/8

0.03150.0305

0.13500.1150 0.1243

0.12360.18780.1873

0.12680.1243

0.00320.000002DU03 3/16

0.19750.1775

025DU0255/32

7/32

5/320.166250.14265 0.1554

0.15470.21910.2186

0.15810.1556

0.00340.0002025DU04 1/4

0.26000.2400

03DU03

3/161/4

3/160.19750.1775

0.18650.1858

0.25030.2497

0.18930.1867

0.00350.000203DU04 1/4

0.26000.2400

03DU06 3/80.38500.3650

04DU041/4 5/16

1/40.26000.2400 0.2490

0.24810.31280.3122

0.25180.2492

0.00370.0002

04DU06 3/80.38500.3650

05DU065/16

3/8

3/80.38500.3650 0.3115

0.31060.37530.3747

0.31430.311705DU08 1/2

0.51000.4900

06DU06

3/8 15/32

3/8

0.04710.0461

0.38500.3650

0.37400.3731

0.46910.4684

0.37690.3742

0.00380.000206DU08 1/2

0.51000.4900

06DU12 3/40.76000.7400

07DU087/16

17/32

1/20.51000.4900 0.4365

0.43550.53160.5309

0.43940.4367

0.00390.000207DU12 3/4

0.76000.7400

08DU06

1/2 19/32

3/80.38500.3650

0.49900.4980

0.59410.5934

0.50190.4992

0.00390.0002

08DU08 1/20.51000.4900

08DU10 5/80.63500.6150

08DU14 7/80.88500.8650

09DU089/16

21/32

1/20.51000.4900 0.5615

0.56050.65660.6559

0.56440.561709DU12 3/4

0.76000.7400

ID and OD chamfersDi Co α Ci β

1/8" - 5/16" 0.008" - 0.024" 30°-45° 0.004" - 0.012" 30°-45°3/8" - 11/16" 0.020" - 0.040" 20°-30° 0.005" - 0.025" 40°-55°

3/4" - 7" 0.020" - 0.040" 15°-25° 0.005" - 0.025" 40°-50°

47

8Standard Products

10DU08

5/8 23/32

1/2

0.04710.0461

0.51000.4900

0.62400.6230

0.71920.7184

0.62700.6242 0.0040

0.0002

10DU10 5/80.63500.6150

10DU12 3/40.76000.7400

10DU147/8

0.88500.8650

11DU14 11/1625/32

0.88500.8650

0.68650.6855

0.78170.7809

0.68950.6867

12DU08

3/4 7/8

1/2

0.06270.0615

0.51000.4900

0.74910.7479

0.87550.8747

0.75250.7493

0.00460.0002

12DU12 3/40.76000.7400

12DU16 1 1.01000.9900

14DU12

7/8 1

3/40.76000.7400

0.87410.8729

1.00050.9997

0.87750.874314DU14 7/8

0.88500.8650

14DU16 1 1.01000.9900

16DU12

1 11/8

3/40.76000.7400

0.99910.9979

1.12561.1246

1.00260.9992

0.00470.000116DU16 1 1.0100

0.9900

16DU24 11/21.51001.4900

18DU1211/8 19/32

3/4

0.07840.0770

0.76000.7400 1.1238

1.12261.28181.2808

1.12781.1240

0.00520.000218DU16 1 1.0100

0.9900

20DU12

11/4 113/32

3/40.76000.7400

1.24881.2472

1.40681.4058

1.25281.2490

0.00560.0002

20DU16 1 1.01000.9900

20DU20 11/41.26001.2400

20DU28 13/41.76001.7400

22DU16

13/8 117/32

1 1.01000.9900

1.37381.3722

1.53181.5308

1.37781.374022DU22 13/8

1.38501.3650

22DU28 13/41.76001.7400

24DU16

11/2 121/32

1 1.01000.9900

1.49881.4972

1.65681.6558

1.50281.4990

24DU20 11/41.26001.2400

24DU24 11/21.51001.4900

24DU32 2 2.01001.9900

26DU1615/8 125/32

1 1.01000.9900 1.6238

1.62221.78181.7808

1.62781.6240

0.00560.000226DU24 11/2

1.51001.4900

28DU16

13/4 115/16

1

0.09410.0923

1.01000.9900

1.74871.7471

1.93811.9371

1.75351.7489

0.00640.0002

28DU24 11/21.51001.4900

28DU28 13/41.76001.7400

28DU32 2 2.01001.9900


s3

WidthB

Shaft-∅DJ

Housing-∅DH


Clearance CD

Di Do B max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

48

8 Standard Products

30DU16

17/8 21/16

1

0.09410.0923

1.01000.9900

1.87371.8721

2.06332.0621

1.87871.8739

0.00660.000230DU30 17/8

1.88501.8650

30DU36 21/42.26002.2400

32DU16

2 23/16

1 1.01000.9900

1.99871.9969

2.18832.1871

2.00371.9989

0.00680.0002

32DU24 11/21.51001.4900

32DU32 2 2.01001.9900

32DU40 21/22.51002.4900

36DU32

21/4 27/16

2

0.09280.0902

2.01001.4900

2.25072.2489

2.43772.4365

2.25732.2509

0.00840.0002

36DU36 21/42.26002.2400

36DU40 21/22.51002.4900

36DU48 3 3.01002.9900

40DU32

21/2 211/16

2 2.01001.9900

2.50112.4993

2.68812.6869

2.50772.5013

40DU40 21/22.51002.4900

40DU48 3 3.01002.9900

40DU56 31/23.51003.4900

44DU32

23/4 215/16

2 2.01001.9900

2.75002.7482

2.93702.9358

2.75662.7502

44DU40 21/22.51002.4900

44DU48 3 3.01002.9900

44DU56 31/23.51003.4900

48DU32

3 33/16

21/22.51002.4900

3.00002.9982

3.18723.1858

3.00683.0002

0.00860.000248DU48 3 3.0100

2.9900

48DU60 33/43.76003.7400

56DU40

31/2 311/16

21/22.51002.4900

3.50003.4978

3.68723.6858

3.50683.5002

0.00900.000256DU48 3 3.0100

2.9900

56DU60 33/43.76003.7400

64DU48

4 43/16

3 3.01002.9900

4.00003.9978

4.18724.1858

4.00684.0002

0.00900.000264DU60 33/4

3.76003.7400

64DU76 43/44.76004.7400

80DU485 53/16

3 3.01002.9900 4.9986

4.99615.18605.1844

5.00564.9988

0.00950.0002

80DU60 33/43.76003.7400

96DU486 63/16

3 3.01002.9900 6.0000

5.99756.18746.1858

6.00706.000296DU60 33/4

3.76003.7400

112DU60 7 73/16 33/43.76003.7400

6.99546.9929

7.18307.1812

7.00266.9956

0.00970.0002


s3

WidthB

Shaft-∅DJ

Housing-∅DH


Clearance CD

Di Do B max.min.

max.min.

max.min.

max.min.

max.min.

max.min.

49

8Standard Products

8.8 DU Thrust Washers - Inch sizes

All dimensions in inch

dP

Di

Do

sT

Ha

Do

d p

dD

Hd

[D10

]

DJ

Part No.

Inside-∅Di

Outside-∅Do

Thickness sT

Dowel Hole Recess DepthHa∅ dD PCD-∅ dP

max. min. max. min. max.min.

max.min.

max.min.

max.min.

DU06 0.510 0.500 0.875 0.865

0.0630.061

0.0770.067

0.6920.682

0.0500.040

DU07 0.572 0.562 1.000 0.990 0.7860.776

DU08 0.635 0.625 1.125 1.115

0.1090.099

0.8800.870

DU09 0.697 0.687 1.187 1.177 0.9420.932

DU10 0.760 0.750 1.250 1.240 1.0050.995

DU11 0.822 0.812 1.375 1.365 1.0991.089

DU12 0.885 0.875 1.500 1.490 0.1400.130

1.1921.182

DU14 1.010 1.000 1.750 1.740 1.3801.370

DU16 1.135 1.125 2.000 1.990

0.1710.161

1.5671.557

DU18 1.260 1.250 2.125 2.115 1.6921.682

DU20 1.385 1.375 2.250 2.240 1.8171.807

DU22 1.510 1.500 2.500 2.490

0.2020.192

2.0051.995

DU24 1.635 1.625 2.625 2.615 2.1302.120

DU26 1.760 1.750 2.750 2.740 2.2552.245

DU28 2.010 2.000 3.000 2.990

0.0930.091

2.5052.495

0.0800.070DU30 2.135 2.125 3.125 3.115 2.630

2.620

DU32 2.260 2.250 3.250 3.240 2.7552.745

50

8 Standard Products

8.9 DU Strip


8.10DUB StripAll dimensions in mm

8.11DU Strip - Inch sizesDU Strip Inch sizes are available as Non-Standard products, on request.

ss

Wu

min

L

W

Part No.Length L

Total Width W Usable Width WU min

Thickness sS

max.min.

max.min.

S07190DU

503500

200 190

0.740.70

S10190DU 1.010.97

S15240DU

254 240

1.521.48

S20240DU 2.001.96

S25240DU 2.502.46

S30240DU 3.063.02

Part No.Length L

Total Width W Usable Width WU min

Thickness sS

max.min.

max.min.

S07085DUB

503500

95 85 0.740.70

S10180DUB

193 180

1.010.97

S15180DUB 1.521.48

S20180DUB 2.001.96

S25180DUB 2.502.46

51

9Test Methods

9 Test Methods9.1 Measurement of Wrapped BushesIt is not possible to accurately measure the external and inter-nal diameters of a wrapped bush in the free condition. In itsfree state a wrapped bush will not be perfectly cylindrical andthe butt joint may be open. When correctly installed in a hou-sing the butt joint will be tightly closed and the bush will con-form to the housing.

For this reason the external diameter and internal diameter ofa wrapped bush can only be checked with special gauges andtest equipment.The checking methods are defined in ISO 3547 Parts 1 to 7.

Test A of ISO 3547 Part 2Checking the external diameter in a test machine withchecking blocks and adjusting mandrel.

Fig. 34: Test A, Data for drawing

Table 14: Test A of ISO 3547 Part 2

Test B (alternatively to Test A)Check external diameter with GO and NOGO ring gauges.

Test CChecking the internal diameter of a bush pressed into a ringgauge, which nominal diameter corresponds to the dimensionspecified in table 6 of ISO 3547 Part 2 (Example Di = 20 mm).

Fig. 35: Test C, Data for drawing

Measurement of Wall Thickness (alternatively to Test C)The wall thickness is measured at one, two or three positionsaxially according to the bearing dimensions.

Fig. 36: Measurement position Table 15: Measurement position

Test DCheck external diameter by precision measuring tape.

Checking block

Split

dch,1

Fch

z

Test A of ISO 3547 Part 2 on 2015DUChecking block and setting mandrel dch,1 23.062 mmTest force Fch 4500 NLimits for ∆z 0 and -0.065 mmBush Outside diameter Do 23.035 to 23.075 mm

20.06120.001

Bush inserted in ring gauge ∅ 23.011 mm

A

A

∅ 0.050

X X measurement position

BB [mm] X [mm] measurement

position≤15 B/2 1

>15 ≤50 4 2>50 ≤90 6 and B/2 3

>90 8 and B/2 3

52

9 Test Methods

Your notes:

©2009 GGB. All rights reserved.www.ggbearings.com

This handbook was designed by Profidoc Silvia Freitag

www.profidoc.de

08-09

Product InformationGGB gives an assurance that the products described in this documenthave no manufacturing errors or material deficiencies.The details set out in this document are registered to assist in assessingthe material's suitability for the intended use. They have been developedfrom our own investigations as well as from generally accessible publi-cations. They do not represent any assurance for the properties them-selves.Unless expressly declared in writing, GGB gives no warranty that theproducts described are suited to any particular purpose or specific ope-rating circumstances. GGB accepts no liability for any losses, damagesor costs however they may arise through direct or indirect use of theseproducts.GGB’s sales and delivery terms and conditions, included as an integralpart of quotations, stock and price lists, apply absolutely to all businessconducted by GGB. Copies can be made available on request.Products are subject to continual development. GGB retains the right tomake specification amendments or improvements to the technical datawithout prior announcement.Edition 2009 (This edition replaces earlier editions which hereby losetheir validity).

Declaration on lead contents of GGB products/compliance with EU lawSince July 1, 2006 it has been prohibited under Directive 2002/95/EC(restriction of the use of certain hazardous substances in electrical andelectronic equipment; ROHS Directive) to put products on the marketthat contain lead, mercury, cadmium, hexavalent chromium, polybromi-nated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE).Certain applications listed in the annex to the ROHS Directive areexempted. A maximum concentration value of 0.01% by weight and perhomogeneous material, for cadmium and of 0.1% by weight and perhomogeneous material, for lead, mercury, hexavalent chromium, PBBand PBDE shall be tolerated. According to Directive 2000/53/EC on end-of life vehicles, since July 1,2003 it has been prohibited to put on the market materials and compon-ents that contain lead, mercury, cadmium or hexavalent chromium. Dueto an exceptional provision, lead-containing bearing shells and bushescould still be put on the market up until July 1, 2008. This general excep-tion expired on July 1, 2008. A maximum concentration value of up to0.1% by weight and per homogeneous material, for lead, hexavalentchromium and mercury shall be tolerated. All products of GGB, with the exception of DU, DUB, SY and SPsatisfy these requirements of Directives 2002/95/EC (ROHS Direc-tive) and 2000/53/EC (End-of-life Vehicle Directive). All products manufactured by GGB are also compliant with REACHRegulation (EC) No. 1 907/2006 of December 18, 2006.

Health Hazard - WarningThere are two separate aspects of health hazard which could arise from certain usage of DU materials.FabricationAt temperatures up to 250 °C the polytetrafluroethylene (PTFE) present in the lining material is completely inert so that even on the rare occasi-ons in which DU bushes are drilled, or sized, after assembly there is no danger in boring or burnishing. At higher temperatures however, small quantities of toxic fumes can be produced and the direct inhalation of these can cause an influenza type of illness which may not appear for some hours but which subsides wit-hout after-effects in 24-48 hours. Such fumes can arise from PTFE particles picked up on the end of a cigarette. Therefore smoking should be prohibited where DU is being machined.

DU® and DU®B are trademarks of GGB.

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