 16-gauge Reynolds 531, a high-tensile manganese-molybdenum steel alloy, was used as it allowed the frame tubes to be made thinner for the same strength, as well as making for a more responsive frame.All the joints were Sifbronze welded, – a relatively low-temperature flame-braze – except for the sub frame which was initially bolted-on but welded in later versions.In 1953 the Norton International was relaunched with a new version of the Featherbed frame made from grade A mild steel.