SD89053 – ASADA Dies HSS 1/4in – 3/8in BSPT Pitch Threading Die Chasers. Other threading chasers available: BSPT, NPT, BSPS, Conduit, BSW, Metric, UNC, UNF, Asada Threading Oil is strongly recommended, Alloy material is for general purpose threading such as black or galvanised pipe and rod & HSS material is for stainless steels and high tensile steels.