The outside ring of six orifices provides a mixture of oxygen and acetylene for the pre-heat flame. Once the metal is up to ignition temperature the trigger is pulled, releasing a stream of pure oxygen from the center orifice. The metal instantly combines with the oxygen forming iron oxide at half the melting point of the metal being cut. The iron oxide particles are blown away by the air stream. Once started, the reaction produces enough heat to continue without any additional heating.
He was cutting the ends off of two broken 8 foot blades by bolting a 6 foot blade to each one a foot short and cutting them into 7 foot sections to combine into a 14 foot blade. MATH IS EVERYWHERE! :O)