Loading ...
Sorry, an error occurred while loading the content.

Drill hole thru drill chuck

Expand Messages
  • Corey Renner
    Now that my toolchanger is done, I ve been moving over most of my Tormach tooling onto CatR8 holders. I ve popped a couple of my chucks off the Tormach arbors
    Message 1 of 3 , Jul 9, 2013
    • 0 Attachment
      Now that my toolchanger is done, I've been moving over most of my Tormach tooling onto CatR8 holders.  I've popped a couple of my chucks off the Tormach arbors and I noticed something strange.  The 1/4" chucks aren't drilled very deep.  The result is that a 1/4" drill held in a 1/4" chuck protrudes farther from the spindle than the same drill held in a 3/8" jacobs chuck despite the shorter length of the chuck.  Not sure why they're designed that way.  I'm thinking about drilling through a couple of them so that they have a thru-hole and can seat a drill much deeper.  I can't think of a reason NOT to do it, and I also can't figure out why they'd be made this way unless it's to save $0.002 on the machining.  A couple are cheapies, a couple are Rohm.  The Rohm ones are the worst as far as OAL.  Google hasn't turned up any answers.  Any ideas?  Any reason not to do this?

      cheers,
      c

    • Edgar
      The drills protrude a good distance because you most likely have a set of jobber length drills. You don t notice this much in the larger drills. The
      Message 2 of 3 , Jul 9, 2013
      • 0 Attachment
        The drills protrude a good distance because you most likely have a set of jobber length drills. You don't notice this much in the larger drills. The diameter/length ratio becomes pronounced when you get to the smaller sizes.

        You can get production drills which are shorter in the smaller sizes.

        The construction of some chucks, e.g. Albrecht, don't have a provision for a through hole. If you ever disassemble an Albrecht ball bearing chuck you will find the the jaws are actuated from the center of the chuck. This is done with a hardened part that looks like ball screw screwed into the chuck body, with a head having 3 slots to engage the chuck's jaws. There are ball bearings that run in the screw and body. This is how you are able to generate large clamping forces on the drill shank and still easily release it just by hand.

        Jacob's style chucks use a split ring and actuate the jaws from the out side of the chuck jaws. These chucks, if I recall correctly, do have a hole through them. What you are looking at inside the chuck is not the chuck body, but the end of the hardened Jacobs taper adapter. You need a pair separator wedges to get it apart. You could then make a new taper adapter with the desired shank out of soft or annealed steel with a through hole.

        I don't think I have ever used a standard drill chuck of any make with a through hole... doesn't mean they wouldn't be useful if they had through hole.

        Orlin in SC/USA

        --- In mill_drill@yahoogroups.com, Corey Renner <vandal968@...> wrote:
        >
        > Now that my toolchanger is done, I've been moving over most of my Tormach
        > tooling onto CatR8 holders. I've popped a couple of my chucks off the
        > Tormach arbors and I noticed something strange. The 1/4" chucks aren't
        > drilled very deep. The result is that a 1/4" drill held in a 1/4" chuck
        > protrudes farther from the spindle than the same drill held in a 3/8"
        > jacobs chuck despite the shorter length of the chuck. Not sure why they're
        > designed that way. I'm thinking about drilling through a couple of them so
        > that they have a thru-hole and can seat a drill much deeper. I can't think
        > of a reason NOT to do it, and I also can't figure out why they'd be made
        > this way unless it's to save $0.002 on the machining. A couple are
        > cheapies, a couple are Rohm. The Rohm ones are the worst as far as OAL.
        > Google hasn't turned up any answers. Any ideas? Any reason not to do
        > this?
        >
        > cheers,
        > c
        >
        > My Blog
        > http://coreyrenner.tumblr.com/
        >
        > My YouTube Channel
        > http://www.youtube.com/user/vandal968
        >
      • BarryL
        Corey, I have the same issue with my Albrecht chinese clone precision chucks. A centerdrill (combined drill/countersink) #4 doesn t go in as far in the clone
        Message 3 of 3 , Jul 10, 2013
        • 0 Attachment
          Corey,

          I have the same issue with my Albrecht chinese clone precision chucks. A centerdrill (combined drill/countersink) #4 doesn't go in as far in the clone as it does in my Albrecht chuck though they are definitely the same mechanism. I am very tempted also to use a carbide drill or endmill and at least deepen the hole since I'm not going to drill it through the integral taper. I am also convinced that there could be no downside to doing this. The problem I have is with that #4 or #5 centerdrill in there, it's double ended flutes make it tend to end up untrue in the chuck because the jaws are trying to clamp on the flutes of the back end. The deeper Albrecht doesn't have this problem.

          Barry

          --- In mill_drill@yahoogroups.com, Corey Renner <vandal968@...> wrote:
          >
          > Now that my toolchanger is done, I've been moving over most of my Tormach
          > tooling onto CatR8 holders. I've popped a couple of my chucks off the
          > Tormach arbors and I noticed something strange. The 1/4" chucks aren't
          > drilled very deep. The result is that a 1/4" drill held in a 1/4" chuck
          > protrudes farther from the spindle than the same drill held in a 3/8"
          > jacobs chuck despite the shorter length of the chuck. Not sure why they're
          > designed that way. I'm thinking about drilling through a couple of them so
          > that they have a thru-hole and can seat a drill much deeper. I can't think
          > of a reason NOT to do it, and I also can't figure out why they'd be made
          > this way unless it's to save $0.002 on the machining. A couple are
          > cheapies, a couple are Rohm. The Rohm ones are the worst as far as OAL.
          > Google hasn't turned up any answers. Any ideas? Any reason not to do
          > this?
          >
          > cheers,
          > c
          >
          > My Blog
          > http://coreyrenner.tumblr.com/
          >
          > My YouTube Channel
          > http://www.youtube.com/user/vandal968
          >
        Your message has been successfully submitted and would be delivered to recipients shortly.