53) The process of forming thin sheet metal by revolving the job at high speed and pressing it against a former attached to head stock spindle is known as

54) In oxy-acetylene gas welding, a carburizing flame is obtained when there is

55) The tool used to support the head of the rivet which is already formed and also prevent the damage to the shape of rivet head during rivetting process is known as

56) If the large diameters of the tapered job is 30 mm and smaller diameter of the tapered job is 26 mm. The length of the tapered job is 100 mm and total length of the job is 200 mm. Then the Tail stock offset required during taper turning in lathe is

57) Colour code for Bins for metal waste segregation is