Series E500 HSS straight flute tap set is manufactured form hardy high-speed steel with a bright finish, ideal or hand or machine tapping in a wide variety of materials. • Straight flute for through or blind holes.
Dormer are a great quality make and this grade is perfect for steel, aluminium and brass etc. I also use them on stainless steel 303 and 304 and they are perfectly capable of cutting a thread in these materials.