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Sharpening End Mills........???

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  • #16
    From what I can tell in your pictures it looks OK. On my fixture the relief angle is like 3 degrees and is ground into the base of the fixture. I believe the larger the dia. of the EM is the deeper the relief will be as shown in your picture with the straight edge across the top.

    JL..................

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    • #17
      Did one more and came out excellent. Tried another brand that was sharpened by hand(not me) and it's back to the drawing board.
      mark costello-Low speed steel

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      • #18
        Originally posted by doctor demo View Post
        Here is a photo (not that great) of an end mill sharpening chart that might be of interest.

        [\Steve
        Seems to me that the function of the chart is the same as those referred to for grinding lathe bits. Optimizing cutting angles and relief for different materials.

        JoeLee, have you read the section on gashing on this page? http://pico-systems.com/sharpen.html Have you read the K.O.Lee book on cutter sharpening?

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        • #19
          Yes I have been reading through the KO Lee manual on end mill sharpening. There are a few different ways to go about it, depending on the type of fixture your going to use. Your mill set up is OK, it gets the job done and is informative for those that don't have a surface grinder or T&C grinder. The gash is the most difficult of operations to do as it requires an angle that the end mill fixture doesn't provide. LIke you said gashing is only needed after several sharpenings. As you mentioned the little fixture doesn't come with any instructions and the initial st up is all by eye, but I've got execellent results with it despite a few mistakes. Practice makes perfect. I think the 11V9 wheel is the best way to go when it comes time to cut the gash. With my other KO fixture I can grind all three faces with out removing the end mill from the fixture, but the only thing I don't like about that fixture is that it requires the use of a finger for positioning. It's more of a time consuming set up and it tends to get in the way. The fixed angle fixture is by far the simple solution to sharpening.

          JL.............
          Originally posted by Rosco-P View Post
          Seems to me that the function of the chart is the same as those referred to for grinding lathe bits. Optimizing cutting angles and relief for different materials.

          JoeLee, have you read the section on gashing on this page? http://pico-systems.com/sharpen.html Have you read the K.O.Lee book on cutter sharpening?

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          • #20
            Not trying to Hijack this but I have a question.

            If an end mill is used for cuts about 0.050" deep and needs to be sharpened will sharpening the end be enough, is that were the cutting takes place or do the sides get dull and need to be sharpened also.
            The shortest distance between two points is a circle of infinite diameter.

            Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

            Southwestern Ontario. Canada

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            • #21
              You need to grind off .055 off of the end mill, then sharpen the bottom.
              mark costello-Low speed steel

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              • #22
                By gash are you referring to the relief cut under the flute lip?

                I sharpen mine like your #1 mill. Not having a divider or indexer, I have a drill chuck on the end of a stepper motor. I then clamp the mess in a multi-axis hobby vise on the mill table and run it by a diamond saw blade chucked in the mill. I use a small CBN wheel for the lips. The stepper does the indexing to keep it all even.

                Works a treat on drill bits, too.
                _________________________

                Eddie "Thread Killer" daGrouch (YouTube channel)
                Smithy CB-1220 (Clark CL500M)

                Sometimes ya gotta re-invent the wheel to learn how to make wheels.

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