<P> The bridge is held together by six million Australian - made hand - driven rivets supplied by the McPherson company of Melbourne , the last being driven through the deck on 21 January 1932 . The rivets were heated red - hot and inserted into the plates ; the headless end was immediately rounded over with a large pneumatic rivet gun . The largest of the rivets used weighed 3.5 kg ( 8 lb ) and was 39.5 cm ( 15.6 in ) long . 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 . </P>
<P> The bridge is held together by six million Australian - made hand - driven rivets supplied by the McPherson company of Melbourne , the last being driven through the deck on 21 January 1932 . The rivets were heated red - hot and inserted into the plates ; the headless end was immediately rounded over with a large pneumatic rivet gun . The largest of the rivets used weighed 3.5 kg ( 8 lb ) and was 39.5 cm ( 15.6 in ) long . 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 . </P>
how many bolts are in the sydney harbour bridge
how many bolts are in the sydney harbour bridge
six million Australian - made hand - driven rivets
six million Australian - made hand - driven rivets