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helicoil fight

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  • #31
    Mr. BigLake, any input on processes is welcomed. I grind a bit of the cutting edge inline with the shank. I guess this would be zero rake. The amount that is ground is shiny in the photo. It's not critical.

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    • #32
      I guessed wrong, Larry!

      If you have zero rake, it would indeed be flat and square to the the bit itself.
      My pic shows an increased rake.

      If you are turning the tool by hand, flat might be practical.

      ....Cotten
      AMCA #776
      Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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      • #33
        So the leading edge would be ground flat to the surface of the material. Like this.zerorake.jpg

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        • #34
          DCoul!

          I believe that appears to be zero rake, but isn't zero rake is actually perpendicular (90) to the surface of the material?
          (Square to the axis of the bit, and hole. It is 'flat' in that it has no chip-breaking curve to it.)

          Zero rake is great for hand-driven cutters, like flat machinists' scrapers and such, as it eliminates "chatter".
          I doubt that would be an issue.

          ....Cotten
          Last edited by T. Cotten; 10-25-2017, 03:05 PM.
          AMCA #776
          Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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          • #35
            Well, I got her done. Drilled the last hole with the correct 17/64 bit. Tapped it. Made my own tool by filing a slot in the end of and old hex wrench. Then grinding the circumference of it a bit smaller. It was still pretty tight and it balked going in. It appears that the windings of the coil get tighter as you screw in the heli-coil so maybe that makes it harder. The tool that came with it was not cutting it.

            I still cut off two threads so the heli-coil would not protrude. Should be plenty of usable thread and able to use original size bolts.

            I'll have to admit, I was speaking a lot of French, I think. And, I had no knowledge that I even spoke French!

            Tinkering on this old bike is usually therapeutic and relaxing. This was not one of those times. My fear is messing up a 75 year old bike.

            Sure not like working on a Twin Cam where you can just go down and buy a part. It's like "living on the edge".

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            • #36
              Imagine, DCoul,..

              What it would be like to do these fossils for a living.

              ....Cotten
              AMCA #776
              Dumpster Diver's Motto: Seek,... and Ye Shall Find!

              Comment


              • #37
                On one hand, I feel like I'm preserving history for another generation. On the other hand, I don't feel like the best steward. Sure will be glad when I can jump on and ride.

                You must have nerves of steel Cotton. Or, you know what you're doing more often that not. I'm learning as I go and what I'm learning I may never use again.

                It's keeping me occupied though. At least it's productive, usually.

                I took the breather out to fix the scavenger pump studs so now I have the cam cover off to re-time the breather gear. Actually getting toward the end. For now.

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