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How to cut a Morse taper - the Easy Way!

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  • How to cut a Morse taper - the Easy Way!

    I ‘ve wanted to make a set of center drill holders for a long time. No matter what project I was working on, it always seemed like I spent half of my time with a chuck key in my hand swapping out center drills with drill bits. However, the thought of cutting a Morse taper (with no taper attachment) had always seemed daunting. After all, how in the world was I going to accurately cut a taper at 1° 26′ 16″?

    Then it occurred to me that I could use my compound to cut a Morse taper since it has plenty of travel. I only needed about 4″ of travel to cut a number 3 morse taper and my compound has nearly 6". Excited, I set to work.

    I set things up using a MT3 drill chuck arbor positioned between centers (the center in the 3-jaw chuck is a sacrificial center that I re-cut at 60° to ensure that it was perfectly centered). I didn’t have an extra arbor sitting around, so I removed the arbor from my lathe’s drill chuck and used that.

    Using a dial indicator (attached to the compound with a mag base) I adjusted my compound to about 1.5° and began sweeping the indicator from one end to the other, making adjustments as needed until the indicator read zero across the entire length of the taper. The Picture below is my attempt at a double-exposure to illustrate the process of sweeping back and fourth along the taper. Make sure that the point of you dial indicator is on the centerline of the part, if it’s high or low you’re taper won’t come out right!

    Once you’re satisfied that your compound is set at the correct angle you’re ready to start cutting your taper. It’s a good idea to have a way to check the size of your taper occasionally. I used a Morse taper sleeve (4/3) for this purpose. Keep test fitting until the taper fits into the sleeve to the right depth. Be sure it fits far enough into the sleeve so that it can be knocked out with a drift, but not so far in that it bottoms out.

    Here’s an image to illustrate how to use a sleeve to check your taper for proper fit. The taper on the top is still too large and doesn’t penetrate the sleeve far enough to be knocked out with a drift. The taper on the bottom has enough of the taper exposed to be knocked out by using a drift in the slot.

    Once you’re satisfied with the size of the taper and the depth of the fit, you can fine tune the angle using layout die (or a Sharpie) and emery cloth. To test the fit draw a line along the taper and slide the sleeve over the taper giving it a few full rotations. The ink will be removed wherever the two tapers make contact.

    Here you can see that my taper rubs in the middle more than at the ends, but it’s making contact along about 2 inches of the taper. With a little fine tuning (polishing with fine grit emery cloth reinforced with a flat backing) I should be able to improve the level of contact even further.

    You’ll notice that my taper doesn’t have a tang. This is because my tailstock doesn’t have a slot in it so tangs are useless for my lathe - they just get in the way.

    However, if you decide to forgo the tang, be sure to turn down the first 0.300 so that you’ll have a protective “button” (for lack of a better term) at the end of the taper. This button is intended to absorb any abuse the arbor might experience over it’s lifetime (from being dropped or deformed by a drift). If the taper were to extend all the way to the end, any damage would cause the taper to not seat properly in the tailstock. Here is a picture of a manufactured live center with a black (hardened) protective button on the end.

    I decided to cut several blank tapers while I had the angle set up. I’d advise you do the same. You can always think of uses for the tapers later!

    This was my first time cutting my own Morse taper, so If I missed anything please leave a comment. I’m sure there are several other methods of accurately cutting a Morse taper, so if you have one, please share your experience!
    Tyler Youngblood

  • #2
    Here's a picture of the completed tapers. The long one on the left will be used for a die holder. The third one from the left will probably become a slitting saw arbor.

    The three on the right were turned into my center drill holders.

    Tyler Youngblood


    • #3
      Very nicely done Tyler. Classy touch with the knurls.


      • #4
        Originally posted by Walter
        Very nicely done Tyler. Classy touch with the knurls.

        The little buggars are hard to hold on to without the knurl. I dropped one right off the bat with a center drill already seated. Luckily it bounced off my rubber shop mat without breaking the center drill or dinging the taper.

        So I decided that a knurl would make them easier to hold on to when swapping them in and out of the tailstock.
        Tyler Youngblood


        • #5
          Great job and nice detail too! Me, I'm too lazy or have less free time. I buy MT-to-JT tapers when they're on sale and cut them up for my needs. I keep a stock on hand for special purposes. (Headstock and tailstock sizes.)


          • #6
            Very nice. Your work looks excellent.


            • #7
              That's an excellent use of the compound. I once asked my journeyman machinist friend what to do to make a taper. He was doing something else at the time in his shop and he said over his shoulder without even looking up.."Just set your compound to match a taper".

              Now I know what he meant. Nice work!


              • #8
                Nice write up and great looking parts. What make and model lathe are you using in the pictures?


                • #9
                  A very interesting and educational post, thanks!



                  • #10
                    great post and nice work! i think i need to make a few of those center drill holders (and some #2 taper shanks).

                    andy b.
                    The danger is not that computers will come to think like men - but that men will come to think like computers. - some guy on another forum not dedicated to machining


                    • #11
                      Super post and good photography and markup. It's also a subject that a lot of people are afraid to try. One thing to point out is that even if the compound doesn't have enough travel to do the cut in one setup it isn't difficult to reset for a second cut since the angle won't change.
                      Free software for calculating bolt circles and similar: Click Here


                      • #12
                        Very nice work,do you intend to blue them or leave them as is?
                        I just need one more tool,just one!


                        • #13
                          Very nice. I like to see someone DO that instead of wussing out*!

                          I cut them pretty much like that myself.

                          A couple points:

                          1) the accuracy of the taper setup is equal to the accuracy of alinement of HS and TS centers. They should be in line at the beginning or the measurement using DTI will be "off". There is compensation, as the compound path will generate the same surface the DTI followed, and theoretically should still make the taper, but some small errors can remain due to the centers being angled in the center holes of the setup piece (looseness). If you used ball centers I think the compensation at small angles would be essentially perfect for any sensible purpose.

                          2) The poster has a very long-travel compound. But if yours is shorter, it is NOT necessary to cut the whole taper length. In many cases, especially where you are going to pull it in with a drawbar, you can leave the small end as an under-size cylinder, without any problems. That may be better than trying to re-set, although there is nothing wrong with re-setting aside from the hassle.

                          Even if you will not use a drawbar, you are likely fine. After all, the large end has the most frictional resistance to turning, it has the largest lever arm.

                          *I've seen all sorts of complicated means for grafting pre-made tapers onto other sections, for milling machine arbors, etc. Most look twice as hard as doing it right to begin with.
                          Last edited by J Tiers; 10-17-2009, 11:32 AM.

                          Keep eye on ball.
                          Hashim Khan


                          • #14
                            Originally posted by CCWKen
                            Great job and nice detail too! Me, I'm too lazy or have less free time. I buy MT-to-JT tapers when they're on sale and cut them up for my needs. I keep a stock on hand for special purposes. (Headstock and tailstock sizes.)
                            I've thought about just using a pre-fab arbor like the one from my drill chuck that I put between centers (its an MT3/JT33) to make center drill holders out of, but I needed a long one for the die holder I'm planning to make (similar to Steve Bedairs design - pictured below).

                            So after cutting the long shank for the die guide I figured I'd cut a few more blanks. However, in the future I'll probably start buying them. Grizzly sells them for about $5 each. Pretty hard to justify making your own if you can adapt a $5 arbor that's ground and perfect.
                            Tyler Youngblood


                            • #15
                              Nice job! Great post. Thanks for your efforts, I know many will find it useful.
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