1、BRITISH STANDARD BS6102-10: 1987 ISO8488:1986 Cycles Part10: Specification for screw threads used to assemble head fittings on bicycle forks UDC629.118.3.011.15:621.882.082BS6102-10:1987 This British Standard, having been prepared under the directionof the General Mechanical Engineering Standards Co
2、mmittee, waspublished under the authorityofthe Board of BSIandcomes intoeffect on 31 March1987 BSI07-1999 The following BSI references relate to the work on this standard: Committee referenceGME/25 Draft for comment84/77398DC ISBN 0 580 15807 1 Committees responsible for this British Standard The pr
3、eparation of this British Standard was entrusted by the General Mechanical Engineering Standards Committee (GME/-) to Technical CommitteeGME/25, upon which the following bodies were represented: Association of Cycle Traders Bicycle Association of Great Britain British Cycling Federation British Rubb
4、er Manufacturers Association Consumer Standards Advisory Committee of BSI Consumers Association Cyclists Touring Club Department of Transport (Highways) Institute of Trading Standards Administration Royal Society for the Prevention of Accidents Small Electrical Appliances Marketing Association Coopt
5、ed member Amendments issued since publication Amd. No. Date of issue CommentsBS6102-10:1987 BSI 07-1999 i Contents Page Committees responsible Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Basic ISO thread profile and basic sizes 1 4 Lim
6、its and tolerances 2 5 Designation 2 6 Gauging system 2 Figure 1 Profiles of BSC and ISO threads 5 Figure 2 Thread profiles and tolerance zones for ISO fittings and fork threads 6 Table 1 Basic dimensions 2 Table 2 Limits and tolerances for screw threads on the fork 2 Table 3 Limits and tolerances f
7、or screw threads on fittings 3 Table 4 Fork limits of size for GO screw ring and calliper gauges, and associated screw check, wear and setting plugs 3 Table 5 Fork Limits of size for NOT GO screw ring and calliper gauges, and associated screw check, wear and setting plugs 4 Table 6 Fittings Limits o
8、f size for GO and NOT GO screw plug gauges 4 Table 7 Fork and fittings Limits of size for GO and NOT GO plain ring or calliper gauges for fork major diameter, and GO and NOT GO plain plug gauges for fittings minor diameter 4 Publications referred to Inside back coverBS6102-10:1987 ii BSI 07-1999 Nat
9、ional foreword This Part of BS6102 has been prepared under the direction of the Mechanical Engineering Standards Committee and forms part of a series implementing corresponding international standards in the development of which the UnitedKingdom has played an active part. This Standard is identical
10、 with ISO8488:1986 “Cycles Screw threads used to assemble head fittings on bicycle forks” prepared by Technical Committee ISO/TC149, Cycles, of the International Organization for Standardization (ISO). Terminology and conventions. The text of the international standard has been approved as suitable
11、for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a
12、full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “Part of BS6102”. Cross-references The Technical Committee has reviewed the provisions of ISO6692, to which reference is made in the text, and has
13、decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confe
14、r immunity from legal obligations. International standard Corresponding British Standard ISO68:1973 BS3643ISO metric screw threads ISO965-1:1980 Part1:1981 Principles and basic data (Technically equivalent) ISO1502:1978 BS919 Screw gauge limits and tolerances Part3:1968 Gauges for ISO metric screw t
15、hreads (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the
16、amendment table on the inside front cover.BS6102-10:1987 BSI 07-1999 1 0 Introduction Inch screw threads of BSC (British Standard Cycle) thread profile are used extensively throughout the world for various applications on bicycle components, and have been standardized in national standards. The purp
17、ose of this document is to provide an International Standard for the particular screw thread used to assemble the head race and locknut on bicycle forks; it is based on the use of the ISO basic thread profile and complies as far as is practicable with existing International Standards for general pur
18、pose screw threads. The change to an ISO system of screw threads will inevitably take a long time to complete in view of the millions of bicycles now in use which employ BSC thread profile inch screw threads and for which replacement spare parts will be required. For this reason, in order to minimiz
19、e changes in production methods during the changeover to the International Standard, and also to secure satisfactory interchangeability with the BSC screw threads now used, the ISO screw thread in this International Standard has the same pitch as that of the1.000in 24t.p.i. BSC screw thread it is in
20、tended to replace. AnM25,522 1,058(1.005in 24t.p.i.) screw thread of ISO basic profile has been adopted in this International Standard. The basic pitch diameter of this thread is identical to the1.000 in 24t.p.i. BSC thread, but, due to the smaller crest truncation of the ISO profile (see Figure 1),
21、 interference may occur at the major diameter when an ISO fork thread made towards its upper limit is assembled with a BSC race/locknut thread made towards its lower limit on major diameter. The possibility of interference occurring in this manner is considered to be unlikely in practice because of
22、the effect of the manufacturing tolerances (ve on the fork and+ve on the fittings) and the usual practice of using high-crested screwing taps. However, a practical investigation has been carried out and has confirmed that there is little possibility of any interference arising in practice. NOTEIn ad
23、dition to the1.000in 24t.p.i. BSC thread referred to above, it should particularly be noted that there exists in the cycle trade other widely used threads: The French and UK threads are clearly not interchangeable with the BSC thread due to outside diameter and t.p.i. respectively. The Italian threa
24、d is also not compatible due to the Italian flank angle of55 compared to the BSC angle of60 . As referred to in the second paragraph above, this ISO system of screw threads is intended to replace the1.000 in 24t.p.i. BSC threading, but the continued usage of the other non-compatible threadings is no
25、t in harmony with the objects of ISO worldwide standardization, and wherever and as soon as possible, it is strongly recommended that all new products change over to the new ISO threads detailed herein. It should also be noted that where the design size of the fork column tube is already25,4mm(1.000
26、in) nominal, the thread cutting of this new ISO thread will increase the truncation and facilitate assembly. Attention should be paid to ISO6692 for the proposals on thread identification marking. 1 Scope and field of application This International Standard specifies details of the screw threads use
27、d to assemble head races and locknuts, i.e.fittings, on bicycle fork steering columns. The basic thread profile is that of ISO68; the tolerance grades and tolerance positions are in accordance with ISO965-1; the gauging system is that specified in ISO1502. Threads to this International Standard are
28、interchangeable with the corresponding BSC (British Standard Cycle) thread. 2 References ISO68, ISO general purpose screw threads Basic profile. ISO965-1, ISO general purpose metric screw threads Tolerances Part 1: Principles and basic data. ISO1502, ISO general purpose metric screw threads Gauging.
29、 ISO6692, Cycles Marking of cycle components. 3 Basic ISO thread profile and basic sizes 3.1 Basic profile The basic profile is that given in ISO68 and is shown in Figure 1. It is the theoretical profile associated with the basic sizes of the major, pitch and minor diameters of the screw thread. 3.2
30、 Basic sizes The basic major diameter, and the basic pitch and minor diameters determined from the basic profile, are given in Table 1. French 25mm 1,0mm (0.984in 25.4 t.p.i.) Italian 25,4mm 1,058mm (1in 24 t.p.i.) UK 25,4mm 0,977mm (1in 26 t.p.i.) USA 25,4mm 1,058mm (1in 24 t.p.i.)BS6102-10:1987 2
31、BSI 07-1999 4 Limits and tolerances 4.1 Fundamental deviations and maximum material limits The fundamental deviations are applied to the basic diameters and establish the maximum material limits. For the fork thread the fundamental (upper) deviations are negative and correspond to tolerance position
32、 “g” on the major, pitch and minor diameters. For the fittings thread the fundamental (lower) deviations are zero and correspond to tolerance position “H” on the major, pitch and minor diameters. 4.2 Tolerance grades, tolerances and limits of size The application of tolerances to the maximum materia
33、l limits, negative tolerances for the fork thread, and positive tolerances for the fittings thread, determines the minimum material limits of size. The tolerances and limits of size are given in Table 2 and Table 3 respectively for the fork and the fittings. The tolerances are grade6 in accordance w
34、ith ISO965-1. The fundamental deviations and tolerance zones are shown in Figure 2. 5 Designation Screw threads made to this International Standard are designated by: a) the nominal diameter of the thread in inch units; b) the pitch of the thread in t.p.i.; c) the tolerance classes of the fittings a
35、nd fork respectively. Example: 1,005 246H/6g 6 Gauging system The gauging system is that laid down in ISO1502 to which reference should be made for details of the thread profiles of the screw gauges and the method of application of the gauges. ISO1502 gives formulae for the calculation of the gauge
36、limits. These formulae have been used to calculate the gauge limits for the fittings and fork in this International Standard, and these limits are given in Table 4 to Table 7. It should be noted that the pitch diameter limits given in Table 4 to Table 6 relate to the simple pitch diameter, and separ
37、ate tolerances are given in ISO1502 for the pitch and flank angles of these gauges. These tolerances are: Pitch tolerance=0,005mm Flank angle tolerance = 159 for profiles with complete flanks = 169 for profiles with truncated flanks Table 1 Basic dimensions Table 2 Limits and tolerances for screw th
38、reads on the fork Nominal diameter of thread in t.p.i. Basic sizes, mm Major diameter Pitch diameter Minor diameter 1.005 24 25,522 24,836 24,379 t.p.i. Major diameter, d mm Pitch diameter, d 2 mm Minor diameter, d 1 mm max. tol. min. max. tol. min. max. 24 25,496 0,180 25,316 24,810 0,125 24,685 24
39、,209 1 2 3 4 5 6 7 8 NOTEThe tolerances given in columns3 and6 are those recommended in ISO965-1 for the nearest metric pitch corresponding to the t.p.i. given in column1. Note that the grade6 pitch diameter tolerance differs from the grade6 major diameter tolerance. The limit for the maximum minor
40、diameter corresponds to a truncation of H/6.BS6102-10:1987 BSI 07-1999 3 Table 3 Limits and tolerances for screw threads on fittings Table 4 Fork limits of size for GO screw ring and calliper gauges, and associated screwcheck,wear and setting plugs t.p.i. Major diameter, D mm Pitch diameter, D 2mm M
41、inor diameter, D 1mm D 3min. D min. max. tol. min. max. tol. min. 24 25,598 25,522 25,006 0,170 24,836 24,615 0,236 24,379 1 2 3 4 5 6 7 8 9 NOTEThe tolerances given in columns5 and8 are those recommended in ISO965-1 for the nearest metric pitch corresponding to the t.p.i. given in column1. Note tha
42、t the grade6 pitch diameter tolerance differs from the grade6 minor diameter tolerance. D 3min. is the diameter to the radiused root of the fittings thread that just clears the crest of a maximum fork thread, assuming no clearance between the flanks of the assembled threads. Dimensions in millimetre
43、s Type of gauge Major diameter Pitch diameter Minor diameter max. min. max. min. max. min. Solid GO screw ring gauge 25,5722 24,815 24,801 24,379 24,365 Adjustable GO screw ring gauge 25,5722 Set on setting plug 24,367 24,363 GO screw calliper gauge Cleared Distance from pitch line to crest is0,229
44、2 GO screw check plug for new solid GO screw ring gauge NOT GO screw check plug for new solid GO screw ring gauge Wear check plug for solid or adjustable GO screw ring gauge Setting plug for GO screw calliper gauge Full profile setting plug for adjustable GO screw ring gauge Truncated profile settin
45、g plug for adjustable GO screw ring gauge 25,505 25,0337 25,0417 25,505 25,505 25,0222 25,487 25,0197 25,0277 25,487 25,487 25,0082 24,797 24,8195 24,8275 24,797 24,808 24,808 24,789 24,8105 24,8185 24,789 24,800 24,800 24,056 6 24,3847 24,3867 24,0566 24,0566 24,0566 BS6102-10:1987 4 BSI 07-1999 Ta
46、ble 5 Fork Limits of size for NOT GO screw ring and calliper gauges, andassociatedscrew check, wear and setting plugs Table 6 Fittings Limits of size for GO and NOT GO screw plug gauges Table 7 Fork and fittings Limits of size for GO and NOT GO plain ring or calliper gauges forfork major diameter, a
47、nd GO and NOT GO plain plug gauges for fittings minor diameter Dimensions in millimetres Type of gauge Major diameter Pitch diameter Minor diameter max. min. max. min. max. min. Solid NOT GO screw ring gauge cleared 24,8967 24,685 24,671 24,4733 24,4453 Adjustable NOT GO screw ring gauge cleared 24,
48、8967 Set on setting plug 24,4733 24,4453 NOT GO screw calliper gauge Thread profile sizes as for NOT GO screw ring gauge GO screw check plug for new solidNOT GO screw ring gauge NOT GO screw check plug for new solid NOT GO screw ring gauge Wear check plug for solid or adjustable NOT GO screw ring ga
49、uge Setting plug for NOT GO screw calliper gauge Full profile setting plug for adjustable NOT GO screw ring gauge Truncated profile setting plug for adjustable NOT GO screw ring gauge 25,380 25,380 25,385 25,373 25,373 25,1058 25,362 25,362 25,367 25,355 25,355 25,0878 24,667 24,6895 24,6945 24,678 24,678 24,678 24,659 24,6805 24,6855 24,670 24,670 24,670 24,0566 24,0566 24,0566 24,0566 24,0566 24,0566 Dimensions in millimetres Type of gauge Major diameter
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