PRECISION IN DEEP BORING

EVEN with versatile, automated machine tools, many equipment manufacturers prefer to rely on an outside specialist to perform one particular metal‐working job that always creates extreme technical problems. Known as deep‐hole boring, it basically entails drilling a straight hole through the centre line of a long metal bar, which may be followed by boring to enlarge the original hole to a precise, uniform diameter and to impart a polished inner‐surface finish. It would seem to be easy, but it is not.