Bsi bs a 298 1988 (2000) iso 8642 1986

BRITISH STANDARD AEROSPACE SERIES BS A 298 1988 ISO 8642 1986 Methods of test for Self locking nuts with maximum operating temperature greater than 425 °C [ISO title Aerospace — Self locking nuts with[.]

Methods oftest for

[ISO title: Aerospac — Self- ocking nuts with m axim um

operating tem perature g reater than42 °C — Test m ethods]

U C 6 9.7.0 :6 1.8 2.3:[ 62 8 2.5 ]6 –9 :6 0.1

This Bri shStan ard, ha ing

b en pre ared u der the

directonof the Aerosp ce

Stan ards Commi e ,was

published u der the

authoriyofthe Bo rd ofBSI

an comes into efect on

2 J n ary1 8

© BSI0 -2 0

The folowing BSI references

relate to the work on this

stan ard:

Commi e reference ACE/ 12

Draft for comment8 / 72 7 DC

ISBN 0 5 0 1 3 2 2

The prep ration of this BritishStand ard was entrusted b the Aerosp ce

Stand rds Commit e ( ACE/-) to Tech ical Commit e ACE/ 12upon which the

fol owing bodies were represented:

Civ il Av iation Authority ( Airworthines Div ision)

Electronic Eng ine ring Association

Ministry of Defence

Society of British Aerosp ce Comp nies Limited

Am endm ents is ued sinc publ cation

Amd No Date of is ue Comments

Commit e s responsible Inside font cov er

Ta le 1 — Bolt d imensions for self-ocking torq ue test at

Ta le 2 — Test bolt coating in relation to the coating ofthe

Ta le 3 — Dimensions of the mandrels for permanent set test 10

National foreword

This BritishStand ard, which has be n prep red under the direction of the

Aerosp ce Stand rds Commit e , is identical with ISO8 42:19 6 “A er ospa ce—

Self-locking n ts wi h ma ximum oper a ting temper a tur e gr ea ter tha n42 °C—

Te t method s” publ shed b the International Org anization for Stand rdization

( ISO)

Term inolog y and conventions The text of the International Stand rd has

be n a prov ed as suita le for publcation as a BritishStand rd without

d ev iation Some terminolog y and certain conv entions are not identical with those

used in BritishStand rds; at ention is d rawn especialy to the fol owing

The comma has be n used as a decimal marker In BritishStand ards it is cur ent

practice to use a ful point on the b selne as the decimal marker

W herev er the words “ International Stand rd” a pear refer ing to this stand rd ,

they should be rea as “BritishStand ard ”

The Tech ical Commit e has rev iewed the prov isions of ISO6 1, ISO/ R1024,

ISO6 0 -1, ISO6 0 and ISO8 41

1)

to which reference is ma e in the text, and

has decided that they are ac epta le for use in conju ction with this stand rd

Related BritishStand ard s to some of the aforementioned International

Stand ards are as fol ows:

A British Stand rd do s not purport to includ e al the neces ary prov isions of a

contract User of British Stand rds are responsible for their cor ect a plcation

Com pl anc with a British Standard does not ofitself confer im munity

f om leg al o l g ations

Summ ary of pag es

This document comprises a f ont cov er, an insid e font cov er, p g esi andi ,

p g es1 to1 , an insid e b ck cov er and a b ck cov er

This stand rd has be n up ated ( se copy rig ht d ate) and ma hav e had

amendments incorporated This wi l be indicated in the amendment ta le on the

inside font cov er

Cros - referenc s

Inte national Stand rd Cor esp nding BritishStand rd

BS629 MJ thr ea d s fr a er ospa ce constr ucton

ISO5 5 -1:19 1 Part1:19 2 Spe ifica tion f r d imensions o ba sic pr ofie

( Identical

ISO5 5 -2:19 1 Part2:19 2 Spe ifica tion f r d imensions f r bol s a nd

n ts

( Identical

ISO7 0 :19 3 BS A29 :19 4 Spe ifica tion fr splne d r ive wr enching

configur a tion

Metric series

( Identical

1)

At present at stag e of draft

Inte national Stand rd Related BritishStand rd

ISO6 1:19 3 BS192:19 2 Spe ifica tion fr open-end ed wr enche

ISO/R1024:19 9 BS417 Method f r R ockwel super ficia l ha r d ne s te t

(Na nd Ts a le )

Part1:19 7 Te tng o meta ls

Part2:19 0 Ver ifica tion o the te tng ma chine

BS427 Method fr Vicker s ha r d ne s te t

ISO6 0 -1:19 2 Part1:19 1 Te tng o meta ls

BS8 1 Method fr R ockwel ha r d ne s te t

ISO6 0 :19 6 Part1:19 2 Te tng o meta ls

1 Scope and field ofappl cation

This International Stand rd specifies test methods

for metric self- ocking n ts with MJ thread s the

ma imum operating temperature of which is

g reater than425°C, intend ed for use in aerosp ce

construction It des ribes the test d ev ice and the

method for each test

Other test d ev ices or test method s than those

specified in this International Stand rd ma be

used, but, in the ev ent of a d ispute, the

requirements laid down in this International

Stand ard shal take precedence

This International Stand rd shal be used in

conju ction with the procurement specification laid

down in ISO8 41

It a ples to self- ocking n ts as defined a ov e,

prov ided that the relev nt d ocuments

( drawing , procurement specification, etc.) refer to

this International Stand rd

2 Ref r nces

ISO6 1, Wr ench a nd socket openings— Metr ic

s r ie — Toler a nc s fr gener a l us

ISO/R1024, R ockwel super ficia l ha r d ne s te t

(N a nd T s a le ) f r ste l

ISO5 5 -1, A er ospa ce constr ucton— MJ

thr ea d s— Pa r t1: B a sic pr ofie

ISO5 5 -2, A er ospa ce— MJ thr ea d s—

Pa r t2: D imensions o bols a nd n ts

ISO6 0 -1, Meta llc ma ter ia ls— Ha r d ne s te t—

Vicker s te t— Pa r t1: HV5 to HV10

ISO6 0 , Meta llc ma ter ia ls— Ha r d ne s te t—

R ockwel te t (s a le A— B— C— D— E— F—

G— H— K)

ISO7 0 , Fa stener s fr a er ospa ce constr uct on—

Splne d r ive wr enching configur a tion— Metr ic

s r ie

ISO8 41, A er ospa ce— Self-locking nuts wi h

ma ximum oper a ting temper a tur e gr ea ter

tha n425°C— Pr ocur ement spe ifica tion

2)

3 Inspections and tests

3.1 Hardnes test

3.1.1 Pr c dure

The authoriz d procedures are as fol ows:

— Rockwel hardnes , in ac ord nce with

ISO6 0 ;

— Vicker hardnes , in ac ord nce with

ISO6 0 -1;

— Rockwel super icial hardnes , in ac ord nce

with ISO/R1024;

— mic ohardnes

3)

It is strong ly recommended to use the method

cor esponding to the hardnes u it indicated

Should this not be pos ible, the use of conv er ion

charts is al owed , but, g iv en their inac uracy , the

results obtained shal be used wariy In the ev ent of

a dispute, the results obtained using the method

cor esponding to the hard nes u it indicated shal

take precedence

3.1.2 Method

This test shal be carr ied out at ambient

temperature

The measurement z ne ( bearing sur ace, ac os

flats, und er ide of anchor n t lug s, etc.) shal

cor espon to the folowing conditions:

a) thick es at least eq ual to10times the

penetration depth;

b) d ev iation in p ral el sm with respect to

bearing sur ace not g reater than3°

Should this not be pos ible, car y out this test on a

cut section after mould ing the n t into a resin

ca a le of maintaining it in the cor ect position

Remov e al pos ible coating ( protection,lubrication,

p int, etc.) in the measurement z ne True up the

bearing sur ace to obtain the required relationship

These two operations shal not g enerate any heat

l a le to mod ify the characteristic of the material

constituting the n t to be tested

Car y out the test and then check conformity with

the req uirements of the d rawing

NOT Nuts subjected to this test shal not b used ag ain

3.2 Bearing sur ac squarenes test

3.2.1 Te t devic

The test dev ice is i lustrated in Fig ure 1

The test d ev ice includes the fol owing elements:

a) a threa ed mandrel with end in ac ord nce

with ISO5 5 -1 and ISO5 5 -2, except for the

pitch diameter which shal be in ac ord nce with

the v alues specified in Ta le 3 for the ma imum

mandrel;

b) a col ar sld ing on the plain portion of the

thread ed mand rel the external d iameter B of

which shal be at least eq ual to reference

dimension A for ty pes I, I I and V I n ts in

Fig ure 2 and equal to reference d imension A for

ty pes I , IV and V n ts in Fig ure 2;

c) an a propriate fe ler g auge

2)

At present at the stag e of draft

3)

W il b de lt wih in a future Internatonal Stan ard

3.2.2 Met hod

The test shal be car ied out at ambient

temperature

For floating n ts, extract the nut fom the cag e or

chan el

Sc ew the thread ed mandrel into the n t or

threa ed p rt u ti it eng ag es with the self-ocking

z ne

Mov e the colar into contact with the bearing

surace

Ev aluate the out-of-sq uarenes b means of a fe ler

g aug e the thick es of which shal cor espond to the

permis ible sq uarenes er or as laid down in the

drawing or the procurement specification

3.3 Axial loa test

3.3.1 Te t devic

The test dev ice is i ustrated in Fig ure 3

The test dev ice includes the folowing elements:

a) a bearing plate in ste l, heat-treated to

HRCW4 ;

b) a bolt with a rol ed threa and characteristic

as folows:

1) thread s:in ac ord ance with ISO5 5 -1 and

ISO5 5 -2,

2) tensi e streng th clas ification: g reater than

that of the n t to be tested,

3) material: al oy ste l, non-coated;

c) a torque wrench

NOT For shan n ts, the sliding colar shal ha e a cou terb re to ac ommodate the shan

Fig ure 1

Fig ure 2

3.3.2 Method

The a ial load is transmit ed to the n t b the bolt,

the n t resting on the bearing plate

3.3.2.1 80% te t

This test shal be car ied out at ambient

temperature

Lubricate the bolt and n t thread s with sy nthetic

aero eng ine oi

Assemble the bearing plate onto the bolt Assemble

the n t and measure the locking torque, using the

torque wrench, when the protrusion is2 pitches

minimum ( including chamfer)

Position the as embly on the tensi e machine Apply

the loa slowly and prog res iv ely in the direction

shown in Fig ure 3 Red uce the loa slowly an

prog res iv ely when the v alue stipulated in the

procurement specification has be n reached

Remov e the as embly f om the tensie machine

Uns rew the n t throug h half a turn and cease

mov ement, then ag ain u s rew and measure the

breakawa torq ue; using the torq ue wrench

Remov e the n t, then submit it to a v isual

ex mination and, if neces ary , to an ex mination

u d er low mag nification after sectioning to check

conformity with the requirements of the

procurement specification

3.3.2.2 10 % te t

This test shal be car ied out at ambient

temperature

I prel minary ex osure to temperature is neces ary

for the test, heat the n t and maintain it at the

temperature stipulated in the procurement

specification; take the nut fom the ov en an alow

it to co l slowly to ambient temperature

Then, in al cases, proce d as d es ribed below

Lubricate the bolt an n t threa s with sy nthetic

aero eng ine oi Assemble the bearing plate onto the

bolt; as emble the n t with a protrusion of2 pitches

minimum ( including chamfer)

Position the as embly on the tensie machine and

a ply the load slowly an prog res iv ely in the

d irection shown in Fig ure 3 Red uce the loa slowly

an prog res iv ely when the v lue stipulated in the

procurement specification has be n reached

Remov e the as embly f om the tensie machine

Remov e the n t, then submit it to a v isual

ex mination and, if neces ary , to an ex mination

u der low mag nification after sectioning to check

conformity with the requirements of the

procurement specification

NOT Nuts subjected to this test shal not b used ag ain

Fig ure 3

3.4 Wrenching feature test

This test a pl es only to wrencha le n ts

3.4.1 Te t devic

The test d ev ice is i ustrated in Fig ure 4

4)

The test d ev ice includes the fol owing elements

)

a) a block of ste l, heat-treated to HRC W 4 ;

b) a bolt with a rol ed threa an characteristic

as fol ows:

1) threa s:in ac ord nce with ISO5 5 -1 an

ISO5 5 -2,

2) tensie streng th clas ification:no p rticular

requirement,

3) material: no p rticular req uirement;

c) a torq ue wrench, hav ing a socket with an

opening tolerance conforming to ISO6 1 for

hex g onal and bihex g onal wrenching or

ISO7 0 for spl ne wrenching

3.4.2 Met hod

This test shal be car ied out at ambient

temperature

Make two flats on the flang e of the nut so that it has

a clearance of0,0 to0,1mm inside the slot,

lubricate the bolt an n t threa s with sy nthetic

aero eng ine oi Insert the modified n t into the slot

Assemble the bolt and moderately tighten it, then

as emble the block into a v ice

Repeat the operations des ribed below the n mber

of times specified in the procurement specification

Apply the torque to the n t, in a tig htening

mov ement, as stipulated in the procurement

specification, with the aid of the torq ue wrench

Remov e, then replace the socket wrench Apply the

same torque to the n t in an u tig htening direction

Finaly , dismantle the as embly , then submit the

n t to a v isual ex mination and, if neces ary , to an

ex mination under low mag nification after

sectioning to check conformity with the

requirements of the procurement specification

N T Nuts subjected to this test shal not b used ag ain

3.5 Torque-out test

This test a ples only to nuts ma e f om more than

one p rt, either b desig n ( floating anchor n ts or

g ang chan el n ts) or for man facturing purposes

( fixed anchor n ts the thread ed element of which is

as embled to the b seplate b brazing or cl nching )

It aims to check that the retention dev ice is a le to

resist rotation of the thread ed portion d uring

tig htening an u tig htening

4)

I is also p s ible to cary out this test wih n ts welded on a block of the same material, the as embly b ing he t tre ted to the

corect le el

Fig ure 4

3.5.1 Te t devic

The test dev ice is i lustrated in Fig ure 5

The test d ev ice includes the fol owing elements:

a) a fixing plate;

b) a shouldered mand rel threa ed in ac ord nce

with ISO5 5 -1 an ISO 5 5 -2

5)

c) a lock ut thread ed in ac ord nce with

ISO5 5 -1 and ISO5 5 -2;

d) riv ets with u iv er al hea s or bolts with

cy lindrical hea s and hex g onal n ts to fix the

n t or the portion of the chan el to be tested

( stand rd iz d aerosp ce fastener );

e) a torq ue wrench

3.5.2 Method

This test shal be car ied out at ambient

temperature

Attach the n t or portion of the chan el to be tested

on the plate b means of rivets or bolts and n ts, the

preformed head s of riv ets or the hea s of bolts being

located on the same side as the element to be tested

Lubricate the mandrel and n t threa s with

sy nthetic aero eng ine oi Sc ew in the mandrel so

that the should er contacts the thread ed element of

the n t ( on bearing surace or bot om of

cou terbore) Apply the torq ue to the n t, in a

tig htening mov ement, as stipulated in the

procurement specification,using the torque wrench

Assemble the lock ut and a ply the same torque in

the rev er e direction using the same procedure

Dismantle the as embly , then submit the thread ed

element as wel as the b se-plate, the cag e or the

chan el to a v isual ex mination and, if neces ary , to

an ex mination u der low mag nification after

sectioning to check conformity with the

requirements of the procurement specification

NOT Nuts subjected to this test shal not b used ag ain

3.6 Push-out test

This test a ples only to g ang chan el n ts and

anchor n ts with the exception of corner n ts shown

in Fig ure 6 and red uced series sing le lug n ts

3.6.1 Te t devic

The test d ev ice is i lustrated in Fig ure 7

A

min

B

3,4 3,9 4,4 5,5 6,5 7,5 8,510,5

Fig ure 5

5)

A shouldered sle v mou ted on a b lt ma also b used

0

–0,0

Fig ure 6

A

min

B

3,4 3,9 4,4 5,5 6,5 7,5 8,510,5

Fig ure 7 0

–0,0

The test dev ice includ es the folowing elements:

a) a fixing plate;

b) a push rod with spherical end ;

c) a bolt with a roled thread and characteristic

as fol ows:

1) threa : in ac ord ance with ISO5 5 -1 and

ISO5 5 -2,

2) tensie streng th clas ification: no p rticular

requirement,

3) material: no p rticular req uirement;

d ) riv ets with u iv er al hea s or bolts with

cy lind rical head s an hex g onal n ts to fix the

nut or the portion of the chan el to be tested

( stand rdiz d aerosp ce fastener )

3.6.2 Met hod

This test shal be car ied out at ambient

temperature

Attach the n t or the portion of the chan el to be

tested onto the plate b means of riv ets or bolts an

nuts, the preformed head s of riv ets or the head s of

bolts being located on the same side as the element

to be tested Apply the a ial loa stipulated in the

procurement specification using the rod with the

spherical end

Using an a propriate fe ler g aug e, ensure that any

permanent d eformation is not g reater than the

v alue stipulated in the procurement specification

Try to s rew a stand rd bolt man aly into the nut,

ev en if deformed, as far as the locking dev ice

Dismantle, then subject the nut as wel as the cag e

an the chan el to a v isual ex mination and, if

neces ary , to an ex mination und er low

mag nification after sectioning to check conformity

with the requirements of the procurement

specification

NOT Nuts subjected to this test shal not b used ag ain

3.7 Self-ocking torque at am bient

tem perature

3.7.1 Te t devic

The test dev ice is i ustrated in Fig ure 8

The test dev ice includes the folowing elements:

a) a ste l sp cer, heat-treated to HRC W 4 ( this

ma be a cy lind rical sle v e or a block with

p ralel faces pier ed with a series of holes)

6)

b) a bolt with a rol ed thread and characteristic

as folows:

For the sing le cy cle test:

1) threa : in ac ord nce with ISO5 5 -1

and ISO5 5 -2, except for the pitch

diameter the minimum an ma imum

dimensions of which are g iv en in Ta le 1,

2) tensi e streng th clas ification: g reate

than or eq ual to that of the n t to be tested,

3) material: al oy ste l, non-coated ,

For the multiple cy cle test:

1) threa : in ac ord nce with ISO5 5 -1

and ISO5 5 -2,

2) material: identical to that of the n t to be

tested ,

3) coating : in ac ord ance with Ta le 2;

c) a torque wrench

Fig ure 8

6)

The same sp cer as for the test des rib d in3.8 ( se Fig ure 9) ma b used