sys lab magazine 310 172

11

National Institute of Metrology (Thailand)

Ministry of Science and Technology of Thailand

Hand torque tools calibration Hand torque tools calibration according to ISO 6789: 2003(E)according to ISO 6789: 2003(E)

NATTAPON SAENKHUMMetrologist

Torque laboratoryDepartment of mechanical metrology

2553 1-2 .. 2553

Assembly tools for screws and nuts-Hand tools-Requirements and test methods for design conformance testing and recalibration

procedure

2



1. Scope

Torque tool 4 ( Classification) indicating setting torque wrench 258 259 ISO 1703: 1983It applies to torque tools in accordance with Clause 4, in particular to indicating and setting torque wrenches in accordance with numbers 258 and 259 of ISO 1703: 1983.

International Standard / Hand torque tools This International Standard specifies the requirements for, and describes the test methods and marking of, hand torque tools used for controlled tightening of bolted connections.

23



2. Classification

a) Type I: Indicating torque tools

Tool that indicates by means of a mechanical scale, dial or electronic display, the value of torque exerted by the tool at the out put drive

- Class A: wrench, torsion or flexion bar- Class B: wrench, rigid housing, with scale or dial display- Class C: wrench, rigid housing and electronic measurement- Class D: screwdriver, with scale or dial display- Class E: screwdriver, with electronic measurement

Hand torque tools International Standard

4



2. Classification


35



2. Classification


6



2. Classification

b) Type II: Setting torque tools

Tool that is pre-set to a certain torque value, so that, when the prescribed value of torque is exerted by the tool at the output drive, a signal is release (e.g. audibly, visibly, perceptibly)

- Class A: wrench, adjustable, graduated or with display - Class B: wrench, fixed adjustment- Class C: wrench, adjustable, non-graduated- Class D: screwdriver, adjustable, graduated or with display- Class E: screwdriver, fixed adjustment- Class F: screwdriver, adjustable, non-graduated- Class G: wrench, flexion bar, adjustable, graduated

47



2. Classificationb) Type II: Setting torque tools

8



2. Classification

b) Type II: Setting torque tools

59



3. Tolerances

a) Indicating torque tools (Type I)

Table 1: Permissible deviation (Type I)

a In the case of torque tools with electronic measurement (Class C and E) and display (Class B and Class D), the value of permissible deviation include the error due to the resolution of the display

4 % 6 %B, C and E

6 %A and D

> 10 Nm 10 Nm

Maximum torque valueClassa

10



3. Tolerances

b) Setting torque tools (Type II)

Table 2 : Permissible deviation (Type II, Classes A, B, D, E and G)

a In the case of torque tools with display (Class A and D), the value of permissible deviation include the error due to the resolution of the display

6 %D, E and G

4 % 6 %A and B

> 10 Nm 10 Nm

Maximum torque value

Classa

611



3. Tolerances

c) Indicating torque tools (Type I) Setting torque tools (Type II)

Table 3 : Permissible deviation (Type II, Classes C and F)

6 %F

4 % 6 %C

> 10 Nm 10 Nm

Maximum torque value

Class

12



4. Calibration

Calibration devices (Torque wrench calibrator Torque screwdriver calibrator) uncertainty of measurement 1% of Rdg, k = 2 95% Guide for evaluation of uncertainty of measurement (GUM)

4.1 Calibration devices

713



4.2 Environment condition

18C 28C 1C 90%RH

4. Calibration

14



4. Calibration

4.3 Calibration condition

815



4. Calibration


20

100

60

40

80

% O F FULL SCALE

ELECTRONIC TRANSDUCER SYSTEM

O FF

PO WERO N

SELECTUNI TS

M EM O RYRESET

AUTORESET

M EM O RYAUTO RESETTRIGGER LEVEL

% OF FULL SCALE

0.7

0.8

1.0

1.2

1.5

1.9 2.54

710

STOP

N. m/LO AD

lbf . f t

lbf . ins

STD

UUC

16



4. Calibration


20

100

60

40

80

% OF FULL SCALE

ELECTRONIC TRANSDUCERSYSTEM

OFF

POWERON

SELECTUNITS

MEMORYRESET

AUTORESET

MEMORY

AUTORESETTRIGGERLEVEL% OF FULLSCALE

0.70.81.01.2

1.5 1.92.547

10

STOP

N.m/LOAD

lbf.ft

lbf.ins

STD

UUC

917



4.4 Calibration sequence

18



5. Calculation1.

( Hand torque tools Type I class Type II class C, F)

( ) ( )r

ras x

xxA 100% =

As(%) Torque tools %xa Torque Toolsxr torque standard

10

19



5. Calculation

( ) ( )r

ras x

xxA 100% =

10..... 10321 rrrr

raxxxxxx +++==

2. torque tools type II class C F

As(%) Torque tools %xa xr

xr torque standard

20



6. Hand torque tools6.1 Hand torque tools

( )sA

ras XXA =

( ) ( )rXrrXaas LbrXrXA = '

11

21



6. Hand torque tools6.1 ()

Torque tools Hand torque tools (Long-term stability)

rXrXaras LbrrXXA +++= 'aXrXXar'brL

Xrr

22

DKD-R 3-8: 2003 ( 1%) DKD-R 3-8: 2003 (Long-term stability) (Error)



6. Hand torque tools6.2

,

( ) 2r22'2r XrXa wwwwAw rXbsC +++=2Xr

w

( )sAwkW CE =

12

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Table 4 Distribution functions

Rel. standard uncertainty of the result in %:

- type B, normal distribution

-Rel. uncertainty of the applied torque value in %

- type B, rectangular distributionrXr

1Resolution of the torque calibration devices, rXr

- type B, rectangular distributionrXa

1Resolution of the torque tools, rXa

- type A, normal distributionRepeatability, b

RemarkRelative standard uncertainty in %ParametersUncertainty component

rb Xn

bw 100'

' =

a

10032 X

rwXar

=

r

10032 X

rwXrr

=

rXw

2X

222' rXrXa

wwwww rrbC +++=

6. Hand torque tools

: 1 Analog scale ra,

1003 X

r

( )( )11

2,

'

==

n

XXb

n

irir

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Table 5 Symbols, units and designations

Nm

Analogue scale: obtained from the ratio of the width of the pointer to the centre-to-centre distance between adjacent scale marks (scale spacing)-recommended ratios are 1/2, 1/5 or 1/10 : spacing not smaller than 1.25 mm are required to estimate a tenth of the scale division.Digital scale: the resolution r is considered to be one increment of the least significant active digit of the numerical indicating device, provided that the indication does not fluctuate by more than one increment when the instrument is unloaded. If the reading (unloaded) fluctuates by more than the value previously determined for the resolution, the resolution should be deemed to be equal to half the range of fluctuation.

NmRepeatability of measurement

NmMean value of

%Relative standard uncertainty of the applied torque value of the torque standard devices

NmIndicated value of torque tools

UnitDesignationSymbol

nXXX rrr ,..., 21

aX

rXw

'b

r

rX


13

25





Table 6 Example of uncertainty budget of setting torque wrench type II class A at 20 Nm

Quantity Estimate Relative Probability Sensitivity Relativestandard distribution coefficient uncertainty v i or v eff

uncertainty contributionX i x i , Nm w (x i ), % c i wi (y), %X a 20 - - - - -

20.28 0.50 Normal 1 0.50 r xa 0 0.29 Rectangular 1 0.29 b ' 0 0.23 Normal 1 0.23 4r xr 0 0.014 Rectangular 1 0.01

Combined relative uncertainty, w C 0.62Expanded rel. uncertainty, WE at k=2 1.24

208A s -0.285M

rX

26



6. Hand torque tools k = 2 95% ( 95.45%) (degree of freedom) (infinity) (effective degrees of freedom) Welch-Satterthwait

( )( )

=

=N

i i

i

ceff yw

yw

1

4

4

( )ywc( )ywi

i

14

27



6. Hand torque tools () 95.45% 7 t-distribution 100 k = 2

28

( )k2TN Mw 7M

V a l u e s o f t p ( V ) f r o m th e t - d i s t r i b u t io n f o r d e g r e e s o f f r e e d o m v t h a t d e f i n e a n in t e r v a l t h a t e n c o m p a s s e s s p e c i f i e d f r a c t i o n s p o f t h e c o r r e s p o n d in g d i s t r i b u t i o n

D e g r e e s o f f r e e d o m

%2 7.6 8= %9 0= %9 5= %4 5.9 5= %9 9= %7 3.9 9=

1 1 .8 4 6 .3 1 1 2 .7 1 1 3 .9 7 6 3 .6 6 2 3 5 .8 0 2 1 .3 2 2 .9 2 4 .3 0 4 .5 3 9 .9 2 1 9 .2 1 3 1 .2 0 2 .3 5 3 .1 8 3 .3 1 5 .8 4 9 .2 2 4 1 .1 4 2 .1 3 2 .7 8 2 .8 7 4 .6 0 6 .6 2 5 1 .1 1 2 .0 2 2 .5 7 2 .6 5 4 .0 3 5 .5 1

6 1 .0 9 1 .9 4 2 .4 5 2 .5 2 3 .7 1 4 .9 0 7 1 .0 8 1 .8 9 2 .3 6 2 .4 3 3 .5 0 4 .5 3 8 1 .0 7 1 .8 6 2 .3 1 2 .3 7 3 .3 6 4 .2 8 9 1 .0 6 1 .8 3 2 .2 6 2 .3 2 3 .2 5 4 .0 9

1 0 1 .0 5 1 .8 1 2 .2 3 2 .2 8 3 .1 7 3 .9 6

1 1 1 .0 5 1 .8 0 2 .2 0 2 .2 5 3 .1 1 3 .8 5 1 2 1 .0 4 1 .7 8 2 .1 8 2 .2 3 3 .0 5 3 .7 6 1 3 1 .0 4 1 .7 7 2 .1 6 2 .2 1 3 .0 1 3 .6 9 1 4 1 .0 4 1 .7 6 2 .1 4 2 .2 0 2 .9 8 3 .6 4 1 5 1 .0 3 1 .7 5 2 .1 3 2 .1 8 2 .9 5 3 .5 9

1 6 1 .0 3 1 .7 5 2 .1 2 2 .1 7 2 .9 2 3 .5 4 1 7 1 .0 3 1 .7 4 2 .1 1 2 .1 6 2 .9 0 3 .5 1 1 8 1 .0 3 1 .7 3 2 .1 0 2 .1 5 2 .8 8 3 .4 8 1 9 1 .0 3 1 .7 3 2 .0 9 2 .1 4 2 .8 6 3 .4 5 2 0 1 .0 3 1 .7 2 2 .0 9 2 .1 3 2 .8 5 3 .4 2

2 5 1 .0 2 1 .7 1 2 .0 6 2 .1 1 2 .7 9 3 .3 3 3 0 1 .0 1 1 .7 0 2 .0 4 2 .0 9 2 .7 5 3 .2 7 3 5 1 .0 1 1 .7 0 2 .0 3 2 .0 7 2 .7 2 3 .2 3 4 0 1 .0 1 1 .6 8 2 .0 2 2 .0 6 2 .7 0 3 .2 0 4 5 1 .0 1 1 .6 8 2 .0 1 2 .0 6 2 .6 9 3 .1 8

5 0 1 .0 1 1 .6 8 2 .0 1 2 .0 5 2 .6 8 3 .1 6

1 0 0 1 .0 0 5 1 .6 6 0 1 .9 8 4 2 .0 2 5 2 .6 2 6 3 .0 7 7 1 .0 0 0 1 .6 4 5 1 .9 6 0 2 .0 0 0 2 .5 7 6 3 .0 0 0

15

29



7. Calibration record ISO/IEC 17025: 2005 General requirements for the competent of testing and calibration laboratories 4.13.2 4.13.2.1 /

30



7. Calibration record4.13.2 4.13.2.1 1. 2. ( 5.4.7) / worksheets work books check sheets work notes control graphs

16

31



7. Calibration record

4.13.2.2

4.13.2.3

32



7. Calibration record

Record no. .Page 1 of 1 page

Work order no. : xxxx Item No. : xxCustomer : National Institute of Metrology (Thailand)Address : 3/4-5 Moo 3, Klong 5, Klong Luang

Pathumthani 12120Equipment : Indicating torque wrench Type: I Class: CMaximum capacity: 100 Nm Resolution: 0.1 Nm Model : xxxxSerial no. : xxxxManufacturer : xxxxEnvironment : 221 C, 5010 %RHCalibration Date : dd/mm/yyyyCalibration Procedure : ISO 6789: 2003(E)

Calibrated by : Checkd by :

Calibration devices :Item Rel.exp.Uncert. %

123

Calibration result :Tolerance limit: 4%Clockwise

% Nm 1st 2nd 3rd 4th 5th Mean 1st 2nd 3rd 4th 5th Mean20 20 20.30 20.35 20.20 20.40 20.15 20.28 -1.48 -1.72 -0.99 -1.96 -0.74 -1.3860 60 61.00 60.80 60.50 60.70 61.00 60.80 -1.64 -1.32 -0.83 -1.15 -1.64 -1.31100 100 101.80 101.50 101.60 101.40 101.00 101.46 -1.77 -1.48 -1.57 -1.38 -0.99 -1.44

Anticlockwise

% Nm 1st 2nd 3rd 4th 5th Mean 1st 2nd 3rd 4th 5th Mean20 -20 -20.30 -20.35 -20.20 -20.40 -20.15 -20.28 -1.48 -1.72 -0.99 -1.96 -0.74 -1.3860 -60 -61.00 -60.80 -60.50 -60.70 -61.00 -60.80 -1.64 -1.32 -0.83 -1.15 -1.64 -1.31100 -100 -101.80 -101.50 -101.60 -101.40 -101.00 -101.46 -1.77 -1.48 -1.57 -1.38 -0.99 -1.44

Uncertainty Budget :ClockwiseNominal Value Rel. exp. Uncert. v eff

% N.m. Repeat. UUCres. STDres. Deviation w rep w UUC res w STD res w STD w C at k=2, WE 20 20 0.52 0.50 0.05 -1.38 0.23 0.14 0.014 0.50 0.57 1.14 14660 60 0.35 0.17 0.02 -1.31 0.16 0.05 0.005 0.50 0.53 1.05 492100 100 0.30 0.10 0.01 -1.44 0.13 0.03 0.003 0.50 0.52 1.04 931

AnticlockwiseNominal Value Rel. exp. Uncert. v eff

% N.m. Repeat. UUCres. STDres. Deviation w rep w res w STD res w STD w C at k=2, WE 20 -20 -0.52 -0.50 -0.05 -1.38 -0.23 -0.14 -0.014 0.50 0.57 1.14 14660 -60 -0.35 -0.17 -0.02 -1.31 -0.16 -0.05 -0.005 0.50 0.53 1.05 492100 -100 -0.30 -0.10 -0.01 -1.44 -0.13 -0.03 -0.003 0.50 0.52 1.04 931

Calibration Record

UUC reading Calibration devices reading in Nm Deviation in %

1.0xxxxTorque wrench calibratorS/N

dd/mm/yyyyDate DueModel

xxxxDescription

UUC reading Calibration devices reading in Nm Deviation in %

Relative deviation in % Relative standard uncertainty in %

Relative deviation in % Relative standard uncertainty in %

17

33



8. Calibration certificate

ISO/IEC 17025: 2005 5.10.2

) ( )) / ) ( )

34




) ) ) ) ) /)

5.10.2

18

35




) ) 1. 2.

5.10.2

36



8. Calibration certificate Certificate No. ?

Uncertainty of measurement ?

Certificate No. ?

Uncertainty of measurement ?

19

37



8. Verification 8 Graphic representation of the results verification

The allowable permissible deviation according to ISO 6789 : 2003 (E) is 6%

This verification chart is concerned of deviation, repeatability, readability and the uncertainty of calibration device.

Rel. Indication deviatin of each measurement results for clockwise and anticlockwise torque

-8

-6

-4

-2

0

2

4

6

8

1 2 3 4 5measurement no.

rela

tive

devi

atio

n in

% o

.r.

-1 Nm

-3 Nm

-5 Nm

1 Nm

3 Nm

5 Nm

tolerance 6%

Rel. Indication deviation of results for clockwise and anticlockwise torque

-8

-6

-4

-2

0

2

4

6

8

-6 -4 -2 0 2 4 6torque in Nm

rela

tive

devi

atio

n in

% o

.r.

sys lab magazine 310 172

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