Drill bits
Close
Login to Your Account
Results 1 to 5 of 5

Thread: Drill bits

  1. #1
    Join Date
    Jan 2014
    Location
    Utica, NY
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default Drill bits

    I recently received a large collection of twist drills from the wife of a deceased machinist.
    Several of the bits have two flats on the shank, at the end of the shank, 180 degrees apart.
    I have done some research, and see that some bits have three flats on the shank to get a more secure grip in the chuck
    are the two flats along the same lines to get a more secure grip?
    or are they for some other purpose?
    Thanks
    Bob

  2. #2
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,169
    Post Thanks / Like
    Likes (Given)
    4470
    Likes (Received)
    1877

    Default

    Assuming you're not talking about little bits for Yankee screwdrivers/drills, I have a vague recollection of a production drilling chuck, probably in the automotive sector, that drove the drill from two flats. The application was stone stupid basic drilling, but the tooling style was very niche. IIRC, those two-flat drills could be driven from an ordinary 3-jawed drill chuck without too many issues. In the worst case, chop the flattened end off the drill and chuck on the round shank.

  3. #3
    Join Date
    Feb 2006
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    12,979
    Post Thanks / Like
    Likes (Given)
    689
    Likes (Received)
    3931

    Default

    Specifically, the bits with two flats are for use in Morse taper adapters, which have bores specific to the bit size. They are called automotive tanged shank bits. They are used in production machinery where the Morse taper shank is superior to a drill chuck and the bit plus adapter is less costly than bits with integral Morse taper shanks. Once the adapter is removed from the driving spindle, a dull bit can be removed by hand and a fresh bit pushed into the adapter. When the adapter and bit are pressed into the spindle, the adapter grips the bit tightly.

    Larry

  4. Likes sfriedberg, Mark Rand, eKretz, mountie liked this post
  5. #4
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,169
    Post Thanks / Like
    Likes (Given)
    4470
    Likes (Received)
    1877

    Default

    Thank you for clearing the fog out of my memory, Larry.

  6. #5
    Join Date
    Jan 2014
    Location
    Utica, NY
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    WOW !!!
    Thank You very much
    the collective knowledge on this forum is amazing
    Thank You
    Bob


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •