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Thread: CBN insert boring?

  1. #16
    Join Date
    Oct 2007
    Location
    Northeast Ohio
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    561
    Al,
    There is a great Youtube channel, Stefan Gotteswinter, and he uses small, often home ground, CBN tools all the time. You may already be aware of his channel, but thought I would throw it out there not as a source of tooling but ideas on how to acquire the pieces/parts and the process needed to make them work.
    Not sure if you have the grinding part of the equation in your shop, but could be helpful if you end up using them frequently.
    Good luck with your search,
    Mike

  2. #17
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,910
    Quote Originally Posted by savet06 View Post
    Al,
    There is a great Youtube channel, Stefan Gotteswinter, and he uses small, often home ground, CBN tools all the time. You may already be aware of his channel, but thought I would throw it out there not as a source of tooling but ideas on how to acquire the pieces/parts and the process needed to make them work.
    Not sure if you have the grinding part of the equation in your shop, but could be helpful if you end up using them frequently.
    Good luck with your search,
    Mike
    I checked it out, thank you

  3. #18
    Join Date
    May 2006
    Location
    Hubert, NC
    Posts
    527

    Boring Hard 17-4

    Hi Al,

    When I was in the business of carving that hard 17-4 and 416, I used coated carbide and ran fast. I would drill as close to bore size as possible, then take cuts of equal amount with plenty of coolant. Light cuts, or slow cutting speed are death to some carbide inserts. The coolant may or may not make a big difference depending on the coating.
    I do use CBN inserts, but for very hard stuff like taking a little off the bottom of a size die or other heat-treated tool steel parts. Over RC 50.
    Last edited by SGS; 01-11-2022 at 09:54 AM.

  4. #19
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,910
    I got a nice one quarter inch pilot hole drilled through the 416 no problem, and I can machine it with my carbide tooling. The 17-4 is an entirely different animal. I wrecked a couple of good drill bits and when I put a carbide end Mill up against it it just squealed, I don't have any long carbide bits and it looks like I'm kind of at an impasse with the 17-4. Both of them are marked at 38 hardness

  5. #20
    Join Date
    Sep 2013
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    Arlington, Virgina
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    1,046

  6. #21
    Join Date
    Feb 2019
    Posts
    685
    Thanks for posting that, Lee.
    It will be very helpful.

  7. #22
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
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    11,910
    Quote Originally Posted by FBecigneul View Post
    Thanks for posting that, Lee.
    It will be very helpful.
    Understatement of the year..... YES, Thank You Lee! That exactly fills my bill.

  8. #23
    Join Date
    Jul 2009
    Location
    Northshore
    Posts
    419
    Quote Originally Posted by Lee Martin View Post
    I have been following this thread. Thanks for the link Lee.
    If anyone has the least bit of interest in pistols do yourself a favor and read through Lee's website.
    Great pictures and even better articles. One day will have to find a way to get a pistol Lee has worked on.
    Stephen

  9. #24
    Join Date
    Jul 2005
    Posts
    705
    Have you tried a hardened HSS tool?

    They can be surprisingly tough.
    Carbide is at its best with faster speeds and larger cuts.
    The larger shavings cary off a lot of heat generated in cutting.

    Properly hardened and tempered HSS is actually pretty tough.

    ETA:
    You can also make a HSS cutter that is within a few hundredths of hole
    diameter for maximum strength.
    Just make sure you can clear the swarf with a channel the length
    of the cutter.
    Last edited by brickeyee; 01-17-2022 at 01:22 PM.

  10. #25
    Join Date
    Nov 2006
    Location
    Augusta, Maine & Palm Coast, Fl
    Posts
    6,580

    There are a number of sellers

    McMaster-Carr has them I just noticed. I was lucky enough to be able to buy a few from a used tool place near where I live summers. They had no idea how to price them so it was my gain, for once. I keep one in a tool holder, ready to go.

    Pete
    Last edited by Pete Wass; 01-19-2022 at 01:24 PM.

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