Tone arm design documents

Thanks to Norman Leach who passed me two drawings for the manufacture of a BAL-AMi tone arm. Norman's cousin was a draughtsman for Balfour in the 1950's. The interesting (one might now consider it daft!) thing about this is that the drawings were made from a supplied sample of the existing USA-made AMi tone arm (which Norman still has). So why go to all the trouble of manufacturing an exact copy from scratch? As you may have read in the history section of this site, it was a requirement that manufactured goods sold in the UK after the War had at least 53% of locally manufactured content. Hence, Balfour decided to make the tone arms in the UK!