An Experiment in the Use of a Standard Limit System

Abstract

The limit system recommended by the British Standards Institution (B.S.I.) was issued first in 1906 and again in 1924, under the title of British Standard Specification No. 164, “Limits and Fits for Engineering”. The engineering industry of this country, it is contended, has found it impracticable to use the tables contained in these publications, and it would appear desirable to ascertain the reason for this striking neglect of so important a publication. There are numerous instances where certain limits have been taken from these publications, but the author is not aware of a single instance where the B.S.I, system is the only system used, and it is claimed that it supplies all the reasonable requirements of a designing draughtsman engaged on ordinary commercial engineering work. This state of affairs cannot be considered as satisfactory and the present paper is put forward in the hope that it will form the basis of a discussion, the findings of which will assist the appropriate committee in making suitable revisions to this British Standard publication.

The paper shows how a genuine attempt was made to use the B.S.I, system for every problem of design and manufacture for which standard limits seemed desirable, and how the system was modified only when it was found impracticable to use it in its original form.