Hex head Bi-metal austenitic stainless steel grade 304 (also available
in grade 316) self-drilling screws with a hardened drill point are used
to fasten sheet metal to steel purlins and rails. High-thread (HT)
screws are recommended for fixing on sandwich panels. Thread dia: #12
(5.5mm), #14 (6.3mm) Thread type: Coarse(???A???), fine(“AB???),
machined(“C???) depending upon drill capacity Length : 1″ – 9″ (25mm –
225mm)