1、BRITISH STANDARD BS 4656-1: 1981 Incorporating Amendment No. 1 Accuracy of machine tools and methods of test Part 1: Specification for lathes, general purpose type UDC 621.9.01 187.001.4:621.941BS4656-1:1981 This British Standard, having been prepared under the directionof the Mechanical Engineering
2、 Standards Committee, was published underthe authority of the Executive Board and comes intoeffect on 30 September 1981 BSI 07-1999 First published December 1970 First revision September 1981 The following BSI references relate to the work on this standard: Committee reference MEE/6 Draft for commen
3、t 80/78071 DC ISBN 0 580 12302 2 Cooperating organizations The Mechanical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: The organizations marked with an asterisk in the above list, together with the followin
4、g, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Associated Offices Technical Committee Department of Trade (Marine Division) Association of Consulting Engineers Department of Transport Association of Hydraulic Equipment Electricity Sup
5、ply Industry in England and Manufacturers Wales Association of Mining Electrical and Engineering Equipment Users Association Mechanical Engineers Federation of Manufacturers of Construction British Compressed Air Society Equipment and Cranes British Electrical and Allied Manufacturers Health and Saf
6、ety Executive Association (BEAMA) Institution of Gas Engineers British Gas Corporation Institution of Mechanical Engineers* British Gear Manufacturers Association Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers* Manufacturers Association Lloyds R
7、egister of Shipping British Pump Manufacturers Association London Transport Executive British Steel Corporation Machine Tool Industry Research Association* British Steel Industry Ministry of Defence* British Valve Manufacturers Association National Coal Board Cbmpe Oil Companies Materials Associatio
8、n Chartered Institution of Building Services Process Plant Association Crown Agents for Oversea Governments and Railway Industry Association of Great Britain Administrations Society of Motor Manufacturers and Traders Department of Industry (Mechanical Limited Engineering)* Telecommunication Engineer
9、ing and Department of Industry (National Engineering Manufacturing Association (TEMA) Laboratory) Water-tube Boilermakers Association Department of the Environment (PSA)* Ball and Roller Bearing Manufacturers University of Aston in Birmingham Association University of Manchester, Institute of Scienc
10、e Federation of British Engineers Tool and Technology Manufacturers Amendments issued since publication Amd. No. Date of issue Comments 7743 August 1993 Indicated by a sideline in the marginBS4656-1:1981 BSI 07-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope 1 2
11、 References 1 3 Application of test methods 1 4 Abbreviations 1 5 Diagrams 1 Appendix A Comments relating to slideway straightness 11 Figure 1 Local deviation from straightness 11 Table 1 Geometrical tests for centre lathes, general purpose type 2 Table 2 Practical test for centre lathes, general pu
12、rpose type 9 Publications referred to Inside back coverBS4656-1:1981 ii BSI 07-1999 Foreword This Part of this British Standard has been prepared under the direction of the Mechanical Engineering Standards Committee and implements agreements of the International Organization for Standardization (ISO
13、). This revision supersedes the1969 edition which is therefore withdrawn. Amendment has been undertaken consequent upon the publication of the1989 edition of ISO1708 to which it is technically equivalent, except where stated below. This standard differs from ISO1708 in the following respects. Clause
14、s. Clauses 1 and3 of this Part of this standard contain the same information that is given in ISO1708 but they are presented in accordance with an accepted format which has been developed for the BS4656 series. Clauses4 and5 have been added. Inch dimensions. In accordance with the UK policy of metri
15、cation, inch dimensions given in ISO1708 have not been included in this British Standard. Tables. In column6 of Table 1 reference to ISO/R230 “Machine tool test code” has been replaced by reference to BS3800. In test G2 column7 b) of ISO1708 it states “The deviation of straightness of carriage movem
16、ent shall, other than in exceptional cases, be concave relative to the axis of the centres”. This note has not been included. In test G15, the qualification that the operation may be deleted if test P3 is carried out has been added. In the observations column of test G15 of ISO1708 there are two sta
17、tements which have not been included in this standard, viz: “However, for both classes of lathes, a record of the lead screw accuracy (over a specified length and checked along four generators shifted90 forward) should be satisfactory. NOTEBy agreement between manufacturer and user on the measuring
18、method and the values of the permissible deviation, total error may be checked over300mm. Practical tests. In test P1 (a), the tolerance for precision lathes has been reduced from0.007mm to0.005mm. In test P2, the proportionality rule (see clause4) has been, more correctly, introduced into the metho
19、d of expressing permissible deviation. In column3 of test P3, it is stipulated that the pitch shall be equal to half that of the lead screw, as this will detect screw thread drunkeness. ISO1708 calls for the pitch to be as close as possible to that of the lead screw, which is not a sufficiently stri
20、ngent test. In tests P1, P2, and P3, the test-piece material is free-cutting steel. ISO1708 calls for steel or cast iron. Appendix. Appendix A has been added. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for the
21、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 12, an inside back cover and a back cover. This standard has been updated (se
22、e copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4656-1:1981 BSI 07-1999 1 1 Scope This Part of this British Standard specifies, with reference to BS3800, both geometrical and practical tests for centre lathes of ge
23、neral purpose type and gives corresponding permissible deviations which apply. This standard is applicable to machines of generalpurpose use and of two classes of accuracy: precision and normal accuracy. It deals only with the verification of accuracy of the machine. It does not apply to the testing
24、 of the running of the machine (vibrations, abnormal noises, stick-slip motion of components, etc.) nor to its characteristics (speeds, feeds, etc.) which should generally be checked before testing accuracy. 2 References The titles of the publications referred to in this standard are listed on the i
25、nside back cover. 3 Application of test methods 3.1 In applying the tests detailed inTable 1 andTable 2, reference should be made to BS3800, especially concerning the installation of the machine before testing, warming up of spindles and other moving parts, the description of measuring methods and t
26、he recommended accuracy of testing equipment. 3.2 The tests may be applied in any order that is practicable and that makes for ease of mounting of instruments or gauging. The sequence in which the geometrical tests are listed inTable 1 is related to the sub-assemblies of the machine and it is not in
27、tended to impose the practical order in which the tests are to be done. 3.3 It is not always necessary for all the tests specified in this standard to be carried out. The purchaser shall be at liberty to select, in agreement with the manufacturer, those tests relating to the properties that are of i
28、nterest to him. The appropriate tests are to be clearly stated when the machine is ordered. 3.4 Practical tests should be made with finishing cuts (e.g. depth0.1mm, feed0.1mm per revolution) and not with roughing cuts, which are liable to generate appreciable cutting forces. 3.5 When establishing th
29、e tolerance for a measuring range different from that given in this standard (see2.311 of BS3800:1964) it should be taken into consideration that the minimum value of tolerance is0.005mm for precision lathes and0.01mm for other lathes for geometrical and practical tests. 4 Abbreviations For the purp
30、oses of this standard, various methods of expressing permissible deviations are employed, each having a particular type of application. The methods employed are as follows. 5 Diagrams For reasons of simplicity the diagrams in this standard illustrate only one type of machine. / This type of expressi
31、on applies to deviations of perpendicularity that are ratios. for any length of This type of expression applies to deviations of straightness and parallelism, and is used in fact for local permissible deviations, the measurement length being obligatory. per This type of expression applies to deviati
32、ons of straightness and parallelism and is used to recommend a measurement length, but in this case the proportionality rule comes into operation if the measurement length differs from that indicated.BS 4656-1:1981 2 BSI 07-1999 Table 1 Geometrical tests for centre lathes, general purpose type All d
33、imensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measuring instruments Observations and references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da u 800 800 1000 0.02+0.01 for each additional 1000 (convex) Local ctolerance: 0.0
34、10 for any length of250 DC 1000 0.03+0.02 for each additional 1000 (convex) Local tolerance: 0.005 for any length of250 Local tolerance: 0.015 for any length of500 Local tolerance: 0.020 for any length of500 b) b) Transverse check: slideways should be in the same plane 0.03/1000 0.04/1000 0.04/1000
35、Precision levels 5.412.7 A level shall be placed transversely on the slideways and measurements taken at a number of positions equally spaced along the length of the slideways. The variation of level measured at any position shall not exceed the permissible deviation a Da means maximum permissible d
36、iameter above the bed. b DC means distance between centres. c See Appendix A.BS 4656-1:1981 BSI 07-1999 3 Table 1 Geometrical tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measuring instruments Observations and
37、references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da u 800 800 1500 0.04 Local tolerance: 0.03 for any length of 500 a Da means maximum permissible diameter above the bed. b DC means distance between centres.BS 4656-1:1981 4 BSI 07-1999 Table 1 Geometrical
38、 tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measuring instruments Observations and references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da u 800 800 800 the measuring
39、length may be increased upto 500 a Da means maximum permissible diameter above the bed. b DC means distance between Centres.BS 4656-1:1981 BSI 07-1999 5 Table 1 Geometrical tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible de
40、viation Measuring instruments Observations and references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da u 800 800 800 the measuring length may be increased up to 500 G8 Measurement of run-out of centre 0.01 0.015 0.02 Dial gauge 5.612.2 and 5.621.2 The value o
41、f the force F to be applied shall be specified by the manufacturer. As the dial gauge is placed perpendicular to the taper surface of the head centre and the tolerance is given in a plane perpendicular to the spindle axis, the readings observed should be divided by cos!, ! being half the included an
42、gle of the taper a Da means maximum permissible diameter above the bed. b DC means distance between centres.BS 4656-1:1981 6 BSI 07-1999 Table 1 Geometrical tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measurin
43、g instruments Observations and references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da u 800 800 800 the measuring length may be increased upto 500 a Da means maximum permissible diameter above the bed. b DC means distance between centres.BS 4656-1:1981 BSI 0
44、7-1999 7 Table 1 Geometrical tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measuring instruments Observations and references to the test code BS 3800:1964 Precision lathes a Da u 500 b DC u 1500 Other lathes Da
45、u 800 800 Da u 1600 G11 Measurement ofthe difference in height between headstock and tailstock centres 0.02 0.04 0.06 Dial gauge and mandrel 5.422.3 The readings shall be taken at the extremities of the test mandrel with the tailstock sleeve withdrawn and locked as under normal working conditions. T
46、he tailstock shall be locked (Tailstock centre higher than headstock centre) G12 Checking of parallelism of thelongitudinal movement of thetop slide to the spindle axis 0.015/150 0.04/300 Dial gauge and test mandrel 5.422.3 Measurements shall be made in a vertical plane (after setting the top slide
47、parallel with the spindle axis in the horizontal plane) only in the working position of the upper slide G13 Checking of squareness of thetransverse movement of thecross slide tospindle axis 0.01/300 Direction of error ! W 90 0.02/300 Direction of error ! W 90 Dial gauge and flat disc or straightedge
48、 3.22 and 5.522.3 a Da means maximum permissible diameter above the bed. b DC means distance between centres.BS 4656-1:1981 8 BSI 07-1999 Table 1 Geometrical tests for centre lathes, general purpose type All dimensions are in millimetres 1 2 3 4 5 6 7 No. Diagram Object Permissible deviation Measuri
49、ng instruments Observations and references to the test code BS 3800:1964 Precision lathes a Dau 500 b DCu1500 Other lathes Da u 800 800 Da u 1600 G14 Measurement ofperiodic axialslip due tocamming ofeach thrust bearing 0.01 0.015 0.02 Dial gauge 5.622.1 and 5.622.2 This operation may be deleted if test P3 is carriedout G15 Checking of the cumulative error generated by thelead screw a) 0.03 deviation over any length of300 b) 0.01 deviation over any length of60 a) DC u 2000. 0.04 deviation over any length
