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Screw Countersink Angles, Cutters

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  • Screw Countersink Angles, Cutters

    Can anyone tell from this link the countersink angle of these screws?

    How about a recommendation for countersink cutters?

  • #2
    C'sink Angles

    For inch fasteners the head is 82 degrees, for metric fasteners the head is 90 degrees. There are usually exceptions and specials but this covers the great majority.


    • #3
      What are 60 degree countersinks typically used for?

      Grizzly doesn't seem to have the same type of cutters for 82 and 90 degree countersinks:

      Is there a significant difference between the 6 flute and the single cutting point type?


      • #4

        They all cut good. The zero flute, the kind with the hole, are less likely to chatter. The 6 flute ones can be run at at slow RPM to keep chatter down. I've never found a need for 60 degree ones.
        90 to 120 RPM works good for all of them.


        • #5
          I actually don't know where you'd find the need for a 60* countersunk hole unless it is a combined drill/countersink for centers.

          I know 100* and 110* countersinks are sometimes used in the aerospace industry, but the two most common are 82* for imperial and 90* for ISO.

          I've heard that single flute countersinks cut better than multiflute but there has been quite a bit of debate about that. What is important is speed and feeds. You can typically avoid chatter with low speed and high feed.

          I would also like to suggest that you consider getting a high quality set. I've used KEO and generic import countersinks and the import ones were a PITA. They were not ground as well as the KEO and tended to chatter much worse. I own my fair share of import cutting tools, but taps and countersinks are two items that I always try to buy quality.

          See here, for instance:


          • #6
            Thanks, I ordered that set from Enco.