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Newb collet question

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  • Newb collet question

    In R8, C5, and ER32 collets, for example, what are the number/letter designations referring to? Also, I watched a video where the guy said if you connect the +12 volt and the -12 volt wires on a computer power supply you would get +24 volts. Is that correct?

  • #2
    I think the number in ER32 is the size in millimeters. Not sure about R8 and C5. Time for Google to be your friend.

    Most computer supplies have a fairly powerful (several amps) +12V output but the -12V is wimpier, several hundred mA. And very often the +5V supply must be loaded to about 10% of capacity for other outputs to be regulated.

    P S Technology, Inc.
    and Muttley


    • #3
      The 3C, 5C etc are just size names. Morse taper are likewise. No idea on R8.

      Keep eye on ball.
      Hashim Khan


      • #4
        "ER" stands for "extended range". They're designed to clamp a wider range of shaft sizes than most other spring collets.

        5C was originally designed by Cataract, who eventually became Hardinge. It was basically Cataract #5, or 5C. Ditto 3C, 16C and others.

        DA collets are "Double angle". Morse tapers are all arbitrary, and I never learned why the R08 was named that.

        Doc's Machine. (Probably not what you expect.)


        • #5
          ER(XX) are tool holding collets and contract at both the front and back of the collet. They can also be used to hold work but not common.
          5C are work holding collets that contract only at the front.
          R8 are tool holding collets that contract only at the front and only good for tools of the same size as the collet is designed for.

          R8 and 5C are just the names for those types of spindles/collets. Many mills have an R8 spindle. You can buy 5C collet blocks and 5C collet spindles for lathes.

          ER(XX) has XX where that determines the overall collet size in MM iirc.

          ER32 and ER24 collets are different sizes and need different collet chucks to hold for example.
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


          • #6
            Just for giggles I just checked some ER32 collets I bought recently with the thought that they might be 32mm across one of the diameters. Nope, the only place an ER32 collet measures 32mm in diameter is at some point down the tapers. The points of maximum diameter where the groove that snaps into the collar is measures up around 1.3 inch. Roughly 34mm.

            So they simply are what they are by name.


            • #7
              Here is a simple chart at the bottom of he page of the ER colets:

              The ER size is indeed a nominal diameter of the collet.
              Amount of experience is in direct proportion to the value of broken equipment.