You can buy 82 degree spot drills from MSC...but in my experience they are prone to chatter for spot drilling.
If I remember correctly, ISO/DIN flathead screws (DIN 7991, and whatever ISO equivalent) use a 90 degree countersink. American made flathead screws use 82 degree countersink. (can still be metric threads, but not conforming to ISO/DIN standard may have 82 degree countersinks)
The different angle is usually small enough to be negligible, unless you have two mating surfaces and the top surface is very thin. (countersink depth can get you in this case...I found this out the hard way)
I really like the 90 degree Minimaster tool/insert from Seco/Carboloy for spotting and countersinking. It is extremely stable and you can feed it at 0.007"/rev for spotting and coutersinking.
Justin |