BS 4656-2 is the second part of the BS 4656 multi-series that discusses the accuracy of machine tools and methods of test.
BS 4656-2 specifies, with reference to BS 3800, both geometrical and practical tests for copying lathes and centre lathes of general-purpose type with copying attachments.
The tests in BS 4656-2 are supplementary to those (except the precision category) in BS 4656-1.
BS 4656-2 is applicable to machines of general-purpose use and normal accuracy.
BS 4656-2 applies to hydraulic and electric servo-controlled copying attachments but not to mechanically-controlled ones.
BS 4656-2 applies to lathes with single-axis copying systems and to lathes where two axes are used in conjunction to produce a profile of up to 180° included angle. BS 4656-2 also applies to capstan and combination turret lathes and vertical boring machines equipped with copying attachments.
BS 4656-2 deals only with the verification of the accuracy of the machine.
Note1: BS 4656-2 does not apply to the testing 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.
Note2: BS 4656-2 does not apply to turning machines equipped with two-axis systems of more than 180° capability which are considered as special-purpose machines, nor does it apply to single- or multi-spindle automatic lathes fitted with a copying attachment.
BS 4656-2 on the specification for copying lathes and copying attachments is useful for:
A copying lathe is a semi-automatic machine that produces components in large quantities, of specific shapes and dimensions from a template of the required object.
The tests described in BS 4656-2 can be applied in any order that is practicable and that makes for ease of mounting of instruments or gauging. The tests provided in BS 4656-2 enable you to verify the accuracy of copying lathes with single and two-axis copying systems in mass-producing components.
Overall, by verifying the accuracy of copying lathes by using the methods of BS 4656-2 you can indirectly verify the quality of your mass-produced components.