how many bolts are in the sydney harbour bridge
Sydney Harbour Bridge The bridge is held together by six million Australian-made hand-driven rivets supplied by the McPherson company of Melbourne,[14][15] the last being driven through the deck on 21 January 1932.[13][16] The rivets were heated red-hot and inserted into the plates; the headless end was immediately rounded over with a large pneumatic rivet gun.[17] The largest of the rivets used weighed 3.5 kg (8 lb) and was 39.5 cm (15.6 in) long.[12][18] The practice of riveting large steel structures, rather than welding, was, at the time, a proven and understood construction technique, whilst structural welding had not at that stage been adequately developed for use on the bridge.[17]