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  • rotary table center holes

    Can anyone tell me why so many rotary tables have Morse taper center holes in them. It seems that everybody is making plugs to plug them... and assist quicker setup...

    What benefit is the Morse taper center? Why don't they make some other center?

  • #2
    bump
    Free software for calculating bolt circles and similar: Click Here

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    • #3
      Mine is a #12 Brown & Sharp! Table dia 16"أ?

      ------------------
      Doug
      Doug

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      • #4
        Mine has a 1 1/8" round hole.

        I have a hunch a taper hole would be more satisfactory, because then the center insert would have no shake, at all, when seated. With a straight hole, there is always some amount of clearance, which translates into shake.

        ----------
        Try to make a living, not a killing. -- Utah Phillips
        Don't believe everything you know. -- Bumper sticker
        Everybody is ignorant, only on different subjects. -- Will Rogers
        There are lots of people who mistake their imagination for their memory. - Josh Billings
        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
        Don't own anything you have to feed or paint. - Hood River Blackie

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        • #5
          Well, is there a functional use for a Morse taper? Maybe for vertical mounting and use as a lathe tailstock using ???? a live center????

          I can't see how the rotary table could be much good with any kind of a Morse taper thing stuck in the hole. Can anyone provide an example??? Or is it the kind of thing where you line up a dead ceneter with a point like you were checking the alignment of your lathe tailstock?

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          • #6
            I put a morse taper with a 1 inch straight stub on it in a 6 or 8 inch rotary table and put the 1 inch straight stub in a collet in the milling machine. I can then clamp the rotary table down knowing it is centered. Saves time.

            Mike

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            • #7
              Not a Morse center -- you'd want, probably, a cylindrical section on the tapered shank, so you could indicate the cylindrical section to center the table, or center work on the table.

              The plug I made for the 1 1/8" round hole in my rotary table sits flush with the top of the table, and has a 1/2" hole in the end of it about 1/2" deep. Into that 1/2" hole I can drop any of a number of custom-made plugs of various diameters to center work on -- for example, if the work has a 1/4" dia. hole in it, I have a stepped plug 1/2" x 1/4" that I can put in, and put the hole in the work onto the 1/4" section.

              The error in all those separate plugs adds up, of course. Ideally I'd have a Morse taper plug with a 1/4" dia. cylinder on the top end of it, to set the work onto, which would be more accurate.
              ----------
              Try to make a living, not a killing. -- Utah Phillips
              Don't believe everything you know. -- Bumper sticker
              Everybody is ignorant, only on different subjects. -- Will Rogers
              There are lots of people who mistake their imagination for their memory. - Josh Billings
              Law of Logical Argument - Anything is possible if you don't know what you are talking about.
              Don't own anything you have to feed or paint. - Hood River Blackie

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              • #8
                I have a set of MT2 collets that fit my RT, so I can sometimes hold work in them. I've drilled holes in clock pinions that way, for a concrete example. I've also made up stub arbors that fit in the MT2 collets and mounted work on the arbor. Putting a center pop on the end of the arbor helps in getting the RT and work centered quickly.

                Regards,

                Jeff E.

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                • #9
                  I made a 2MT adapter drilled on the small end for a draw bolt, and with the spindle nose thread of the small lathe on the other end. This is very useful when the table is mounted vertically, because work can be started on the lathe, then the chuck unscrewed and transfered to the R/T on the mill without disturbing the set up. Works particularly well when a tailstock can be used on the mill to provide extra support. It can also be used with the table horizontal for light cuts, but the chuck needs to be restrained or it tends to unscrew.

                  The adapter is also handy for using the metal working chucks on the wood lathe which has a 2MT spindle, though I avoid this if possible.

                  franco

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                  • #10
                    My table has a 3MT hole and I purchased an unhardened Jacobs adapter with that taper. I turned the OD down to the bore size of a workpiece that I plan to make a bunch of and drilled, bored, and reamed a 0.400" hole in the center of it. Now I can quickly center the table with my 0.2" center finder in the hole and then just drop a workpiece on the OD and start working. Saves a lot of time. The 3MT fit in my lathe spindle so turning the OD and boring the hole was fast, easy, and accurate also. Perhaps that is why they used MT instead of a straight bore.

                    Oh, I also drilled a smaller hole in the bottom of the 0.4" bore and tapped it 1/4-20. A 1/4-20 x 3" bolt with a sliding weight on it makes a very effective removal tool. A quick tap with the weight and the taper comes right out.

                    Paul A.
                    Paul A.
                    SE Texas

                    Make it fit.
                    You can't win and there IS a penalty for trying!

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                    • #11
                      Damn! I have a 12-16" (?) Kearney and Trecker and an 8" Palmgren X-Y and tilt rotary, and neither has a nice tapered center hole. I just have the 1-2.5" straight center hole.

                      Someday I have to make some kind of center plug for both of them so I can get work centered on the table more easily...

                      The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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                      • #12
                        Just a dumbass idea i guess, I have two tables one has a four jaw chuck on it and the other has a three jaw chuck on it. Both of my rotary tables (one vintage the other a bridgeport table have straight bored holes in the centre. Even if yours has a taper you can machine a straight plug that just fits into it and mount your chuck (centre it that is) and fasten it down.)

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                        • #13
                          If you don't need a 1-2.5 inch hole, why not make a 1-2.5 round insert with a MT inside of it. You would be best to have flats on it and some set screws to hold it in.

                          Mike

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                          • #14
                            <font face="Verdana, Arial" size="2">Originally posted by coles-webb:
                            If you don't need a 1-2.5 inch hole, why not make a 1-2.5 round insert with a MT inside of it. You would be best to have flats on it and some set screws to hold it in.

                            Mike
                            </font>
                            My big (Spanish made) table has a stepped parallel centre hole, the makers offer an MT adapter pretty much as you describe as an option.

                            Tim

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                            • #15
                              <font face="Verdana, Arial" size="2">Originally posted by coles-webb:
                              If you don't need a 1-2.5 inch hole, why not make a 1-2.5 round insert with a MT inside of it. You would be best to have flats on it and some set screws to hold it in.
                              Mike
                              </font>
                              Yeah, that's the obvious solution, and you're right, that's what I should do. Now where's that damn rountuit?
                              The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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