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making Er16 collet chuck

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  • making Er16 collet chuck

    i needed an er16 collet chuck for my stepper motor.

    purchased two from ebay: "er16 collet chuck motor extension"



    i've had much luck with chinese tools, but this time... it was a terrible experience.

    the specs said if i purchased 8mm ID for motor shaft, I would receive 7.98mm shaft so i could induction heat it, then put it on the shaft



    however, i recieved 8.1mm oversized hole, so i couldn't use it... too much runout.



    took over a month for it to arrive, wasn't going to wait again.



    based on google and forums er collet chucks have 8 degree internal taper angle



    my compound was not gonna have the accuracy required,

    so i used a bevel protractor to get the precision within 0.1 degrees, which for ER collets is enough



    even greater precision could be set, if i purchased electronic bevel protractor, but it would cost me over $600 for quality one.

    i just went with vernier one, which wasn't too bad.



    below is the link to the making vid of this collet holder



    feel free to comment

    https://youtu.be/bQxgMjGpD48

  • #2
    I haven't watched the vid yet, but you can set the 8 degree to your level of measurement by using one of the collets themselves, assuming they're good ones. Anyway, if you chuck an appropriate piece of stock in the chuck to turn down to a snug fit on your chosen collet, you can then mount the collet on the stub arbor. With an indicator set on the compound, at lathe center height, adjust the compound so it track the collet without indicator movement. I make ER-32 collet chucks and use a sine bar to set the compound and consider it good enough when I get a tenth or less deviation moving the compound. Using the collet itself means you're depending on it to be correct and you've got much less travel to watch for variation but it should be good enough.
    .
    "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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    • #3
      Nice video. Why do you need an ER collet chuck on a stepper motor?
      *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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      • #4
        Originally posted by Bob La Londe View Post
        Nice video. Why do you need an ER collet chuck on a stepper motor?
        just for a simple cnc machine

        Comment


        • #5
          Originally posted by TGTool View Post
          I haven't watched the vid yet, but you can set the 8 degree to your level of measurement by using one of the collets themselves, assuming they're good ones. Anyway, if you chuck an appropriate piece of stock in the chuck to turn down to a snug fit on your chosen collet, you can then mount the collet on the stub arbor. With an indicator set on the compound, at lathe center height, adjust the compound so it track the collet without indicator movement. I make ER-32 collet chucks and use a sine bar to set the compound and consider it good enough when I get a tenth or less deviation moving the compound. Using the collet itself means you're depending on it to be correct and you've got much less travel to watch for variation but it should be good enough.
          hm, i've heard you could set the agle correctly without the collet.
          you need to have DRO though.
          just indicate the inside taper of the er collet chuck, and use trig. to figure out the appropriate Z and X amount.
          very simple indeed. need calculator though

          Comment


          • #6
            Originally posted by dovidu View Post
            hm, i've heard you could set the agle correctly without the collet.
            you need to have DRO though.
            just indicate the inside taper of the er collet chuck, and use trig. to figure out the appropriate Z and X amount.
            very simple indeed. need calculator though
            Or use small sine bar to set the reference angle, check with test indicator. (edit: did I read anything what was already written?)
            Or two dial indicators mounted temporarily to lathe instead of DRO. Better if one of them is long stroke (1") version.

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            • #7
              Originally posted by MattiJ View Post
              Or use small sine bar to set the reference angle, check with test indicator.
              Or two dial indicators mounted temporarily to lathe instead of DRO. Better if one of them is long stroke (1") version.
              oh sinebar, that should be more accurate. what i ve used is bevel protractor. i indicated the bevel protractor, which was quite easy.

              Sent from my LGM-K120L using Tapatalk

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              • #8
                you don't need a fancy protractor or DRO- just put some blue on the inside of the bore, insert the collet lightly with a piece of bar stock in it, and spin the collet. If the blue wipes evenly, your angle is good. If not, adjust compound and try again.

                allan

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                • #9
                  one way to get tapers dead on is turn a male part, set it up on sine bar, indicate it, semi loosen the compound, tap tap tap gently with a brass hammer and try again. It's easier than it sounds and the basic way to get perfect tapers with basic measuring equipment.
                  in Toronto Ontario - where are you?

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                  • #10
                    Seems like far too much bother, why not just bore out the 8.1mm hole and press in a bush and finish bore to 7.98mm.

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                    • #11
                      Bluing against a known good taper is the best way IMO. When I made my Er 20 collet holder I made a male master along with an er16, and 32 while I was dialed in. It's all well and good to make stuff to the #'s and standards, but fit and finish are what matters in the end, so if you can measure directly, cut out the middle man and go direct.

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                      • #12
                        Bluing the final taper is a great way to use for testing. But on something like an ER chuck by the time you know it's wrong it's pretty much too late unless you do the check when you've still got about 1mm of material to remove off the ID to go. So the check needs to be done while the collet is still sticking out proud of the final depth.

                        There is certainly "more than one road to Rome" and any number of options to set the compound angle will work. But do do so to within 0.1° by using a is one fine trick. That must be one fancy bevel protractor ! ! ! ! Looking around at google images of bevel protractors only the very best has any better a chance than half a degree.

                        I don't have one of those and I don't have a sine plate or gauge blocks. And besides, even with all that we still need a dial gauge. So my choice would be as mentioned earlier and make up a turned true stub and with that still held true I'd slide on one of the collets so it's a firm sprung fit and then with the dial gauge in the tool holder adjust the compound angle until there's zero runout and call it a day. In effect using one of the collets as my sine plate.
                        Chilliwack BC, Canada

                        Comment


                        • #13
                          If you absolutely have to reproduce the internal taper, then 0.1 degrees is not good enough. You need to setup one of the existing er holders running true in a four jaw chuck better than 0.0005" tir. Then with a lever indicator (plunger dti will not do) set up with its pivot vertical and the tip exactly on the centreline to get the compound angle perfect. Then you can finish bore the taper with the tip of the boring tool exactly on the centreline. If the indicator or the boring tool are not exactly on centre, the taper will be wrong.
                          I still think the sleeve in my post #10 would be easier. Also, an 8mm spindle on that er collet seems as about as stiff as wet spaghetti.

                          Comment


                          • #14
                            Originally posted by BCRider View Post
                            Bluing the final taper is a great way to use for testing. But on something like an ER chuck by the time you know it's wrong it's pretty much too late unless you do the check when you've still got about 1mm of material to remove off the ID to go. So the check needs to be done while the collet is still sticking out proud of the final depth.

                            There is certainly "more than one road to Rome" and any number of options to set the compound angle will work. But do do so to within 0.1° by using a is one fine trick. That must be one fancy bevel protractor ! ! ! ! Looking around at google images of bevel protractors only the very best has any better a chance than half a degree.

                            I don't have one of those and I don't have a sine plate or gauge blocks. And besides, even with all that we still need a dial gauge. So my choice would be as mentioned earlier and make up a turned true stub and with that still held true I'd slide on one of the collets so it's a firm sprung fit and then with the dial gauge in the tool holder adjust the compound angle until there's zero runout and call it a day. In effect using one of the collets as my sine plate.
                            Lots of bevel protractors come with nonius scale that gives you degree split to 5 minutes. So you can read it to 60/5=20 = 0.05 degree accuracy. But even that is still kind of coarse for any taper.

                            Using existing ER collet to indicate is also bit risky business IMO. Lot depends on how well the collet "settles" to rod without external clamping like its normally used.
                            Partly same problem if you use blue.

                            Comment


                            • #15
                              I would venture to say that the compound slide on the lathes
                              that most of you home shop guys have has more slop than
                              the accuracy required to set and cut the angle needed for
                              precision collet taper setup work. I would thoroughly scrutinize
                              the slideways and the gib for wear and proper adjustment
                              before attempting a precision job like this if you want to
                              achieve satisfactory results.

                              -Doozer
                              DZER

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