• There are no items in your cart

BS 426:1969

Current
Current

The latest, up-to-date edition.

Specification for fixed centres for use on machine tools and in other applications
Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

12-15-1969

Co-operating organizations
Foreword
1 Scope
2 Materials
3 Constructional requirements
4 Finish
5 Designation
6 Marking
Figures
Tables

Materials, dimensions, tolerances, finish, etc., for three types of fixed centre for machine tools and auxiliary equipment, and for other suitable circumstances such as inspection or gauging equipment.

1.1 This British Standard relates to fixed centres for use on machine tools and their auxiliary equipment, and in any other suitable circumstances such as on inspection or gauging equipment, etc.

1.2 The fixed centres specified in this standard fall into the following three series:

  • Type 1. Fixed centre, long series, standard Morse taper shank. This type utilizes the Morse taper shank details, and conforms to relevant dimensions contained in ISO/R 2961), ISO/R 2982) and BS 1660-13). The section forward of the gauge plane includes a parallel cylindrical portion (see Figure 1). When this type is fitted with a tungsten carbide tipped nose cone the amount of regrinding of the tip is strictly limited. Details showing the extent of regrinding are given in Figure 5.
  • Type 2. Fixed centre, short series, standard Morse taper shank. This type conforms to Type 1 in respect of the dimensions rearward of the gauge plane. The section forward of the gauge plane conforms in part to Type 1, but it is arbitrary whether a parallel cylindrical portion is included forward of the gauge plane or whether the Morse taper is extended (see Figure 2).
  • Type 3. Half centre, long series, standard Morse taper shank. This type utilizes the same basic dimensions as Type 1 with the exception that a portion of the centre forward of the gauge plane is cut away parallel to the axis of the centre (see Figure 3).

NOTE The dimensions of the cutaway area align with those of DIN 806, “Lathe centres (60°)”.

1) ISO/R 296, “Self-holding tapers for tool shanks”.

2) ISO/R 298, “Lathe centres. Sizes for interchangeability”.

3) BS 1660, “Machine tapers”, Part 1, “Self-holding tapers and gauges for self-holding tapers”.

Committee
MTE/1
DevelopmentNote
Supersedes 67/23591 DC (08/2005) Reviewed and confirmed by BSI, October 2012. (09/2012)
DocumentType
Standard
Pages
14
PublisherName
British Standards Institution
Status
Current

Standards Relationship
ISO 298:1973 Similar to

BS 970-2:1988 Specification for wrought steels for mechanical and allied engineering purposes Requirements for steels for the manufacture of hot formed springs
BS 1660-1:1992 Machine tapers Specification for shanks and sockets with self-holding tapers (Morse and metric 5%)
BS 1134:1961 Centre-line-average height method for the assessment of surface texture
BS 891-1:1962 Method for Rockwell hardness test Testing of metals
BS 3730:1964 Assessment of departures from roundness
BS 4276:1968 Specification for hard metal for wire, bar and tube drawing dies

View more information
US$143.74
Excluding Tax where applicable

Access your standards online with a subscription

Features

  • Simple online access to standards, technical information and regulations.

  • Critical updates of standards and customisable alerts and notifications.

  • Multi-user online standards collection: secure, flexible and cost effective.