Co-operating organizations

The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations:

Associated Offices’ Technical Committee

Association of Consulting Engineers.

Association of Mining Electrical and Mechanical Engineers

Board of Trade

British Chemical Plant Manufacturers’ Association\

British Compressed Air Society

British Electrical and Allied Manufacturers’ Association

British Gear Manufacturers’ Association

British Internal Combustion Engine Manufacturers’ Association

British Iron and Steel Federation

British Mechanical Engineering Federation

British Railways Board

Crown Agents for Oversea Governments and Administration

Electricity Council, the Generating Board and the Area Boards in England and Wales

Engineering Equipment Users’ Association

Gas Council

Institute of Marine Engineers

Institution of Civil Engineers

Institution of Gas Engineers

Institution of Heating and Ventilating Engineers

Institution of Mechanical Engineers

Institution of Mechanical Engineers (Automobile Division)

Institution of Production Engineers

Locomotive and Allied Manufacturers’ Association of Great Britain

London Transport Board

Machine Tool Trades Association

Ministry of Defence, Army Department

Ministry of Defence, Navy Department

Ministry of Labour (H.M. Factory Inspectorate)

Ministry of Power

Ministry of Public Building and Works

Ministry of Technology — National Engineering Laboratory

Ministry of Transport

National Coal Board

National Physical Laboratory (Ministry of Technology)

Radio Industry Council

Royal Institute of British Architects

This British Standard, having been approved by the Mechanical Engineering Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on 22 September 1966

The following BSI references relate to the work on this standard:

Foreword

In order to keep abreast of progress in the industries concerned, British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due course brought to the notice of the committees charged with the revision of the standards to which they refer.

A complete list of British Standards, numbering over 4000, fully indexed and with a note of the contents of each, will be found in the British Standards Yearbook, price 15s. The BS Yearbook may be consulted in many public libraries and similar institutions.

This standard makes reference to the following British Standards:

BS 1044, Gauge blanks.

BS 1134, Centre-line average height method for the assessment of surface texture.

BS 3730, Methods for the assessment of departures from roundness.

This standard has been prepared under the authority of the Mechanical Engineering Industry Standards Committee. It forms one of a series of standards, published and in course of preparation, for engineers’ precision tools and has been prepared with the co-operation of the manufacturers and in close collaboration with the National Physical Laboratory. It provides only for metric setting rings; similar requirements for inch rings are given in a separate standard.

Numerous types of instruments are now available for the measurement of internal diameters. They vary in design, application and accuracy of performance. Many of these instruments effect measurements by means of two-point contacts but some use three-point contacts and indicate a derived diameter and others, notably air gauges, do not use contacts at all.

The present standard covers requirements for plain rings intended for setting such instruments and suitable for use with those employing two-point or three-point measuring contacts and with those which are independent of physical contact. They are in three grades of accuracy and the standard has been based on considerations aimed at providing a series of plain setting rings that will serve for all types of internal measuring equipment whilst at the same time avoiding the high costs entailed in manufacturing unnecessarily close to a specified size.

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 confer immunity from legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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 amendment table on the inside front cover.

Introduction

The first requirement for a setting ring is that its measuring surface is cylindrical to within close limits. The actual diameter of the ring is relatively unimportant providing its size is known, or known to be within specified limits. Separate tolerances have therefore been allocated for truth of cylindrical form and for departure of diameter from nominal size; thus, Columns 2 and 3 of the table in 5.4 give values designed to ensure that the bore of the ring is round and parellel within limits consistent with its grade of accuracy and Column 4 gives the recommended maximum departures of the mean measured diameter from the nominal size specified by the user. Although, as has already been stated, the actual diameter of the ring is less important than its geometrical form, it is nevertheless essential to know, when setting an instrument, how closely the size stated for the ring has been established and Column 5 accordingly specifies the accuracy of determination appropriate to the various grades.

Further, when considering the diametral tolerances for setting rings, it is important that the effect of possible departures from ideal roundness be clearly understood. It is a well known fact that uniform diametral measurements of a cylinder, obtained by using two diametrically opposite measuring contacts, do not necessarily mean that the cylinder is truly circular in section. It may suffer from departures from ideal roundness. Measurement of a cylinder by means of three contacts, for example, may reveal form deviations undetected when only two opposite contacts are used. In order to ensure that departures from roundness can be expressed numerically and consistently controlled and assessed, a British Standard, BS 3730¹⁾, has been published and deals in detail with the numerical assessment of departures from ideal roundness. All references in the present standard to the departures of setting rings from ideal roundness are based on the procedures recommended in BS 3730.

The standard calls for all setting rings to be examined for departures from ideal roundness. This is to ensure that any ring complying with the standard will be suitable for checking all types of internal measuring equipment regardless of whether two or three measuring contacts are employed.

1 Scope

1.1

This British Standard relates to plain setting rings primarily intended to be used, either singly or in combination, for checking the scales on internal diameter measuring equipment.

It provides for a range of metric rings in sizes from 2 mm to 150 mm in three grades of accuracy, viz.

NOTE Sizes below 2 mm are not included because it is impracticable to measure them.

Requirements are specified for material, hardness and surface texture and recommended sections for the setting rings covered by this standard are included in an appendix.

2 Material and hardness

2.1

3 General features of design

3.1

4 Surface texture

4.1

5 Accuracy

5.1 General.

5.2 Geometric form.

5.3 Measured size.

5.4 Accuracy of determination.

6 Certificate and marking

6.1 Certificate.

6.2 Marking.

BS 4064:1966

Specification for plain setting rings for use with internal diameter measuring machines. Metric units

Current

Published:

22 Sep 1966