" Another tool used everywhere at the shipyard was the hand forged spanner. It had an open end that fitted the nut, which in many cases was square shaped and had many different types of threads. The other end was pointed so it could be used as a "feeler" or to match the holes up so the bolts that held the plates together could be inserted.
Even though the millimetre system was introduced at the start of the 20th century, it was difficult to get rid of the old system, which consisted of different sized threads.
The new directors of the shipyard discarded the old system and bought new combination spanners etc. at the end of the fifties."